Tornado Catamaran Building Instructions From 1979

license

Introduction: Tornado Catamaran Building Instructions From 1979

TimAnderson

Attachments

download {{ file.name }}

Step 1: Tornado Catamaran Olympic Trials 1967 AYRS Report

Recommendations.

Miniature Concrete Bridge Construction

Text Contest

Text Contest

Make it Resilient

Make it Resilient

Farm to Table Contest

Farm to Table Contest

These are the Houlton building plans, developed by Jerry Houlton and a community of Tornado builders around 1980.



These descriptions were originally intended to be used together with the ITA/ISAF issued plans, but it is quite straightforward to build a boat without the ITA/ISAF plan sets. Jerry Houlton stopped building Tornados a long time ago, but these plans lived on thanks to Tornado afficiando Kevin Cook in the USA. Kevin has continously supplied amateur Tornado builders with plans, in a non-profit attempt to keep the wooden Tornado alive. It was trough Kevin the plans used for digitizing was sourced, during christmas 2004.

Amateur buildt Tornados are an important piece of Tornado history, and these digitized plans will hopefully keep this part of the Tornado story living in the 21. century. The original idea behind having the Tornado as an olympic class, besides adding a multihull to the olympic scene, was to have a boat you could build in your backyard and go to the olympics with. And for the first years this was the way it was done, but alas, no more..

A lot has happened with the Tornado since these plans were used to produce competitive boats. Today Marstrms Nomex honeycomb, pre-preg epoxy, autoclaved space-age boats rules the class.A carbon mast has also been added to the boat, further removing the class from it's humble olympic ideals. However, wooden boats can still be high-performers, and these plans combined with some creative thinking can produce very stiff and fast hulls. An effort to modernize amateur buildt Tornados by using a mixture of polystyrene foam bulkheads and maximum fullness hulls are discussed on the Yahoo TornadoCat list. If you, the reader, has ideas and opinions about how the amateur can produce even better Tornados, or just want to get in touch with other Tornado sailors, please join the fray at the TornadoCat forum.

In addition to the Houlton plans, an uncomplete set of russian plans from the '80s have surfaced. Some additional information can be learnt by studying these images. The russian plans was for a boat to compete in one of the olympics during the '80s.

Copyright: There has been done some research to discover wether these plans are subject to copyright or other intellectual property issues. As far as it has been possible to ascertain, publication of these plans does not infringe on any rights. Please let us know if we are mistaken. If you build a set of hulls, or a boat, pleace contact the ITA (http://www.tornado.org) to have it registered, measured and get the necessary payment information for the building fee.

A zip file containing all these images plus a 32 page .pdf (Adobe Reader) building manual is . For revisions, and to have experiences and facts added to the plan sets,
please contact Rolf Nilsen at the Yahoo TornadoCat list.

construction-notes-beam-chocks

construction-notes-bow-hullside-detail

construction-notes-bow-spacer-cutting-jig

construction-notes-bulkhead-bow-spacer-location

construction-notes-centerboard-trunk-dimensions

construction-notes-deck-beam-and-stringers

construction-notes-deck-jig

construction-notes-fitting-beam-chocks

construction-notes-fitting-beam-chocks-and-dish

construction-notes-for-keel

construction-notes-gunwale-and-panel-bevels

construction-notes-hull-side-dimensions

construction-notes-hull-side-layout

construction-notes-inside-glass-cloth

construction-notes-installing-deck-beams

construction-notes-installing-trunk-centerboard

construction-notes-keel

construction-notes-keel-angle-jigs-2

construction-notes-keel-angle-jigs

construction-notes-locating-trunk-start

construction-notes-rigging-rear-beam

construction-notes-rigging-rudders-and-rudderstocks

construction-notes-transom-location

photos1-4

photos5-8

photos9-12

photos13-16

photos17-20

photos21-24

photos25.28

photos29-32

Russian Tornado Plans

Russian Tornado Plans

Russian Tornado Plans

Russian Tornado Plans

Russian Tornado Plans

Russian Tornado Plans

Russian Tornado Plans

Russian Tornado Plans

 

Great choice! Your favorites are temporarily saved for this session. Sign in to save them permanently, access them on any device, and receive relevant alerts.

  • Sailboat Guide

Tornado Catamaran

Tornado Catamaran is a 20 ′ 0 ″ / 6.1 m catamaran sailboat designed by Reg White and Rodney March and built by Sailcraft Ltd., Marstrom Composite AB, and Windrush Yachts starting in 1966.

Drawing of Tornado Catamaran

Rig and Sails

Auxilary power, accomodations, calculations.

The theoretical maximum speed that a displacement hull can move efficiently through the water is determined by it's waterline length and displacement. It may be unable to reach this speed if the boat is underpowered or heavily loaded, though it may exceed this speed given enough power. Read more.

Classic hull speed formula:

Hull Speed = 1.34 x √LWL

Max Speed/Length ratio = 8.26 ÷ Displacement/Length ratio .311 Hull Speed = Max Speed/Length ratio x √LWL

Sail Area / Displacement Ratio

A measure of the power of the sails relative to the weight of the boat. The higher the number, the higher the performance, but the harder the boat will be to handle. This ratio is a "non-dimensional" value that facilitates comparisons between boats of different types and sizes. Read more.

SA/D = SA ÷ (D ÷ 64) 2/3

  • SA : Sail area in square feet, derived by adding the mainsail area to 100% of the foretriangle area (the lateral area above the deck between the mast and the forestay).
  • D : Displacement in pounds.

Ballast / Displacement Ratio

A measure of the stability of a boat's hull that suggests how well a monohull will stand up to its sails. The ballast displacement ratio indicates how much of the weight of a boat is placed for maximum stability against capsizing and is an indicator of stiffness and resistance to capsize.

Ballast / Displacement * 100

Displacement / Length Ratio

A measure of the weight of the boat relative to it's length at the waterline. The higher a boat’s D/L ratio, the more easily it will carry a load and the more comfortable its motion will be. The lower a boat's ratio is, the less power it takes to drive the boat to its nominal hull speed or beyond. Read more.

D/L = (D ÷ 2240) ÷ (0.01 x LWL)³

  • D: Displacement of the boat in pounds.
  • LWL: Waterline length in feet

Comfort Ratio

This ratio assess how quickly and abruptly a boat’s hull reacts to waves in a significant seaway, these being the elements of a boat’s motion most likely to cause seasickness. Read more.

Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam 1.33 )

  • D: Displacement of the boat in pounds
  • LOA: Length overall in feet
  • Beam: Width of boat at the widest point in feet

Capsize Screening Formula

This formula attempts to indicate whether a given boat might be too wide and light to readily right itself after being overturned in extreme conditions. Read more.

CSV = Beam ÷ ³√(D / 64)

The TORNADO first appeared as winner of the 1967 international “B” class catamaran trials. It was an Olympic class from 1976-2008. The class rules were changed to allow twin trapezes, ‘flat head’ mainsail, and asym. spinnaker.(2004?)

Embed this page on your own website by copying and pasting this code.

  • About Sailboat Guide

©2024 Sea Time Tech, LLC

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Construction Header

Tortured Plywood

The name 'tortured ply' certainly carries a negative ring. But within the limits of the system, that need not be so. The 'torture' comes from the fact that plywood is being bent more than is normal on a small boat and this is more safely achieved with the help of hot water applied to the outer veneers. Because plywood bends more readily at 90 degrees to the grain, it is used in that manner and for each half, the bend at the middle of the boat length will closely resemble a quarter-arc of a circle. So if two flat sheets are first attached together along their long edge, then the combined panel can be curved up to formed a shape close to that of a semicircle.

Claims that this 'torturing' will permit compound curvature are not strictly correct as only the very exterior wood fibres are affected by the damping—but still, such forming can certainly be more extreme that what one commonly experiences with dry plywood.

This semi-circular form lends itself admirably to long slim catamaran hulls, that do not depend on their individual shape for stability. (So by implication, it is therefore NOT suitable for monohull kayaks or canoes that need a tighter, more outboard bilge curve combined with some flat-of-bottom.)

The beam of any catamaran hull intended to be built using tortured ply, will depend on the thickness and type of plywood to be used. One of the most flexible of the marine plys is Okoume or Gaboon, so we will first consider working with that.

So just how far can you bend ply before it fails? Woods vary so much that it's hard to predict exactly, but let's have a shot at it. If we are talking about the recommended okoume marine ply , then from tests, I've found it can be bent in its easiest way (perpendicular to the grain) to a radius of about 300 × t², (with t in inches) and about 500 × t² if bent parallel to the grain.

By soaking the outer skins, I think it would be possible to use these figures for practical use for a tortured ply boat and if we also assume that we're to have a semi-circular section, then the minimum possible beam would equal 600 × t².

So based on the above formula, here is a rough graph of what 'minimum beam' you probably need to accept for a semicircular hull, plotted against each specific thickness of plywood. Each sheet will no doubt vary slightly from these test figures and plys of ⅜" and thicker are likely to be proportionally stiffer as the wetted surfaces will affect a lower percentage of the total plywood thickness, but the graph can still be a good starting point.

tornado catamaran building plans

However, if you are using denser plywood (such as a meranti or equal), you'd have to increase these figures by about 50% and with Douglas Fir plywood, I am not sure I'd even try it as it splinters too easily and is typically full of surface flaws.

tornado catamaran building plans

The most famous use of tortured ply is probably its original use to construct hulls for the lightweight 'Tornado' catamaran. In 1979, using 4.5mm ply for the hulls, she outperformed all the other B-class competition, to then be selected as a new Olympic Class - still raced today. Although the method is still used by some today, the actual Olympic boats are now honeycomb sandwiched in graphite. The tortured ply system is more difficult to build to exact dimensions. Here is a picture from the original building manual. More details on how a Tornado hull can be created, can be found online at: www.instructables.com

There is also an interesting article on line about a builders experience making Tornado hulls using tortured ply. http://www.ptwatercraft.com

You'll note that the interior is lightly glassed and a foam/glass stiffener is incorporated into the forward ½ of the hull about ½ way down the hulls. The picture (above left) is from Gougeon's fine boatbuilding book.

The process is to first attached the two side sheets together and then, after soaking the part of the ply requiring the most curve, to curve up the sides with the help of ratchet straps until the deck edge can be fitted into a pre-built deck jig. This will considerably help to control the final shape and once the gunwales and any bulkheads are fitted, the hull is reasonably stable in shape. Once totally dry, the thin skin can be epoxied and even lightly sheathed for additional stability and strength.

tornado catamaran building plans

Some claims have been made that tortured ply hulls have poor shape and 'plunge through waves' etc. but this depends on what they are used for and the Tornado example is a proof that some can work very well. The two ends can be very differently formed and that helps considerably to control pitching.

tornado catamaran building plans

As far as using the system for larger boats, it's seldom been done. One could consider using two layers of thin ply to get a better shape through smaller radii or the chart above indicates that a 5-ft beam hull could be made with 5 ⁄ 16 " ply and if heavily sheathed for strength with FG cloth and added stringers, this could conceivably work for a trimaran main hull—though in such a case, it would be a design more for space than for speed. Depth could be added with an additional strip of ply joined with a 3–4" butt-strap located under a stringer.

tornado catamaran building plans

  • The system is simple, inexpensive and quick.
  • The only building frame or jig is really the deck frame.
  • Boat section shapes are very limited. The ply will bend to create close to a ½ circle bilge at the stern.
  • The ply panel will be under some stress for quite a long time and this can make it more susceptible to damage if further stressed or impacted.
  • To help deal with the stress, examples of this concept beyond that of a beach cat, will really require fibreglass sheathing and this will add weight and cost.
  • The bow shape is very fine and with some designs, may not give enough buoyancy to resist pitch poling.

"New articles, comments and references will be added periodically as new questions are answered and other info comes in relative to this subject, so you're invited to revisit and participate." —webmaster

"See the Copyright Information & Legal Disclaimer page for copyright info and use of ANY part of this text or article"

International Tornado Class Association

1997-2003 A Brief Tornado History

International Status was granted to the Tornado as a result of its outright winning of the IYRU Trials held in England. The next step, adding the Catamaran event to the Olympic program, occurred two years later, with the result that the first Catamaran event, sailed in 1976 in Canada, was sailed in the Tornado. The Tornado is an outstanding example of a class that was designed specifically for Olympic competition that has become a successful International class on its own merits.

The Tornado has since remained unchallenged as the ultimate one-design catamaran. With its modern, stylish rigging and sleek lines the Tornado is quick to catch the eye of any water-drawn on-looker as it speeds across harbors, lakes, and oceans in over 30 countries around the world. With its ability to reach speeds of 15-18 knots upwind and downwind, and 33+ knots reaching, the Tornado is truly the purists’ speed machine.

Over 4,800 Tornados have been built, with 1,200 class association members worldwide. In 2004, on the Saronikos Gulf in Greece, the Tornado will be sailing in its seventh Olympic Games.

Except for refinements in technical details – improvements in hull, sail, and spar technology, better blocks and lines – the Tornado was unchanged from its beginnings in to the early 90’s. Then, as a result of the increasing popularity of other, smaller catamarans, the Tornado class undertook a major development program in 1993. It was specifically to respond to a request from the IYRU to search for ways to improve the public and media awareness of the sport of yachting, and secondarily to answer the possible challengers to its ‘top cat’ role.

Two weeks of intensive on-the-water testing and development took place in Miami, following considerable discussion and planning. Among the participants were the three medalists from Barcelona as well as designer Reg White. The International Tornado Association spent nearly US$22,000 on the testing, evaluation, reporting, and finally balloting process to the class membership, to find the fairest and best ways to improve the class and the sport in ways acceptable to the sailors.

The testing involved 10 standard and fully competitive Tornados, one boat with a larger main and jib, and two boats with a variety of sailplans that included spinnakers of up to 32 sq. m. Fourteen races were run over the testing period in addition to in-line speed and handling evaluations.

As part of the testing process, new courses were also used, most involving a leeward gate.

Following the testing and regatta, the following points were clear; the larger main/jib combination was only marginally faster than the standard rig, and the spinnaker boats were a surprise, only beating the standard rigs in 2 of the 14 races. The ITA then balloted the class membership, with not only the conclusions but also all of the data and the testing procedure, helping to provide insights to the rig selection process.

https://www.tornado-class.org/wp-content/uploads/2023/11/360_F_459272345_9iFTzDInBSozCB66TVrEzEtGfOE42CoO.png

A two-thirds majority is required by the class constitution to implement any change; this majority was not reached, the class voting against the expense of a change with no real benefit to sailing. Thus the class retained the same sailplan for the next two Olympics. The course changes, giving the possiblity of better spectator access and greater media coverage, received the votes necessary to be adopted by the class.

The Class felt then that the changes in course, rather than changes in the equipment, would have a greater impact on public awareness and media coverage. Courses are adjustable in length for wind, thus giving a fixed racing time for the event, and the shorter-than-before course also tend to keep the boats closer, making the racing more exciting and more easily viewed. The fixed Start/Finish lines also is a help, allowing faster turn-around times between races. The new course formats have been in use in the World Championship beginning in ’93, and have proven popular with both the sailors and committees, and are continued today.

The issue of changes in the boat were revisited in 1999, when the ISAF decided to have a Multihull Evaluation Trials in France to look at “possible replacements” in the Olympic program for the Tornado. At the time, there were a number of technical changes in materials that allowed for better spinnakers, and better control, and there were then a number of successful double-trapeze plus spinnaker catamarans on the market in the Tornado size range – 20 feet – that were becoming popular.

The Trials were interesting. Except for the custom, all-carbon Marstrom 20, the standard Tornado dominated upwind, beating all production challengers from Hobie, Nacra, Mystere, and others. Only by piling on sail area, plus a spinnaker, were any of the challengers able to beat the Tornado around the race course, and even then the advantage disappeared as the wind increased. But the extra athleticism needed to sail with a double trapeze, and the extra visual interest provided by the spinnakers, was undeniable, and the final outcome was that the ISAF decreed that the equipment for the 2004 Olympics would be the “Tornado with double trapeze and spinnaker”, and left it up to the class how to implement the changes.

The class took an approach that allowed some development and testing, with the goal of keeping crew weight in the same range as with the old rig. The final result, approved by the class in early 2001, were both evolutionary and radical. First was a new mainsail with a flat top and more area, providing more heeling moment to compensate for the double instead of single trapeze and help keep crew weights with the same range. Second, done to clear the trampoline to make spinnaker work possible, was to redesign the jib. The new jib had the same area, but was longer on the luff and shorter on the foot to allow it to be sheeted to the main beam. Interestingly, this change, moving the sail area forward, overcame one of the Tornado’s handicaps, tacking, and made this maneuver much easier. The innovation of a self-tacking jib appeared later in 2001, and was quickly adopted by the entire fleet. Finally, of course, there was the spinnaker, and the class set only size limits, allowing the question of spinnaker handling equipment to be settled on the race course. Again, the advantages of spinnaker launching tubes quickly established themselves, and became a class standard. Interestingly, the two biggest boathandling improvements, the self-tacking jib and the spinnaker tubes, were quickly adopted by the classes below the Tornado, especially the International Formula 18, which was becoming the Tornado trainer for future Olympians.

Crew Weight

The one-design (as opposed to one-manufacturer) Class Rules have allowed the Tornado Class to insure close racing from sailing like-designs, but with the ability to alter the shape of the sails within the approved sailplan to control power. This has allowed teams to be competitive regardless of weight combination or stature, an important feature of the Tornado that has survived the years and the change to the new rig.

The problem often associated with one-manufacturer classes, where in addition to the boats the sails are also strictly controlled, is that a standard weight/height combination dominates. With the ability to alter the sail shape within the Tornado sailplan has resulted in a class where minimum crew weight is not necessary; in the final results in a Tornado event, it is common to have teams whose total weight varies by 40 kg to appear in the top 10.

Another advantage of the one-design concept with multiple manufactures is the freedom to allow competitors to build such things as rudders and boards, and to do their own rigging. This insures increased strength and extended competitive life of components as modern materials become available at lower cost. An example of this; from a one-manufacturer class rudder replacement can become costly if the materials chosen by the manufacturer years ago cannot be upgraded. Over the years, the Tornado class rules have changed to allow for material improvements in many of the details, especially sails, to take advantage of improvements.

Rigging also has high replacement cost. If a manufacturer chooses lower-grade materials to keep the “new purchase price” low in order to be competitive in the retail market place, it is the active competitor who pays extra by having to constantly replace the lower-grade components. A fine example of this is the traveler on modern catamarans; on the Tornado, modern technology has lead to a dramatic decrease in replacement costs, as parts can be mixed from a variety of sources.

Pieces of the absolut first wooden Tornado ever build back in 1967 K 1 ( later KA1) by Reg White are now in Australia owned by John Forbes, who had the chance to buy the mostly damaged hulls some years ago(2020).

First Boat 1967

https://www.tornado-class.org/wp-content/uploads/2020/03/IMG_8732.jpg

Life Expectancy

The natural technological evolution of materials, plus the push for the sailors for stronger boats at the same weights, has allowed the Tornado Class to increase its competitive life dramatically since the late ’80s. While having a reputation as fragile and short-lived back in the ’70s, the modern Tornados have racing lives of 7-10 years, probably with the availability of much reliable technology and hardware like these  bronze boat screws . Many of the world’s Tornado sailors, who actively race in other catamarans, know well that the modern production boats have top-level racing lives of 1-3 years.

One of the major causes for the low resale value of the one-manufacturer boats is that they are often supplied at major events. This saves the competitor no money, since they have to have the boats to qualify to get to the top events. These supplied boats, which are then sold cheaply by the manufacturer after the event, actually hurt the most active racers by lowering the resale values of their won boats.

The rules of the Tornado class have also resulted in sails that have long racing lives, the result of the competition among sailmakers for quality and durability. One-manufacturer sails, on the other hand, are mass produced at the cheapest price that the manufacturer is willing to gamble with, from materials that are not the quality of open classes. The result again is that the racing competitor pays more, buying more sails to stay on top.

https://www.tornado-class.org/wp-content/uploads/2023/11/rules.png

Class Rules

Rules are modified as needed and wanted by the sailors themselves, to allow the Tornado to advance with modern technology yet always considering the long-term effectiveness of the changes.

The Olympic status of the Tornado has brought some of the finest sailors from all over the world to the class. With over 22 nations regularly attending the annual World and Continental championships, and with the medals won at the Olympics going to sailors from all the continents where the boat is active, the Tornado has a world-wide level of racing matched only by a very small handfull of other classes.

The Class Rules allow the boats to progress with technology and let modern materials such as carbon fiber, nomex, epoxy resins, and high-grade aluminum to be used as they fall in price and can be incorporated into the boat, resulting in constantly improving quality. This helps resale values and enables the Tornado to maintain its marque as the ultimate speed machine; to this day, closing in on 40 years after it birth, the Tornado is still the fastest one-design production boat in the world.

For the immediate future, the class is concerned with ways to bring in more modern, lighter materials while maintaining the one-design nature of the boat, and done in such a way that the purchase price of a new boat can be contained.

The Tornado: in its first Olympics, it was the fastest and most spectacular of the Olympic classes. Now, after the turn of the century, it is still that boat, the fastest, most exciting,most spectacular of the Olympic boats.

This article originally by John Forbes of Australia, 5-time World Champion and Bronze (92) and Silver (00) medallist, with updates by Jim Young, one of the major coaches in the class since 1981.

WOULD YOU LIKE TO BE MEMBER OF THE TORNADO CLASS?

Meet the tornado.

  • Yachting World
  • Digital Edition

Yachting World cover

World’s coolest yachts: Tornado catamaran

Yachting World

  • April 20, 2021

We ask top sailors and marine industry gurus to choose the coolest and most innovative yachts of our times. This month, Carolijn Brouwer nominates the Tornado catamaran

tornado catamaran building plans

“The Tornado catamaran is a really cool boat. It was my introduction to high performance sailing and it had a big influence on me in many ways.

“Once you get a taste for it, there is no way back. Sailing the Tornado opened up different doors for me in my sailing career,” says Carolijn Brouwer .

The Tornado catamaran was for many years the fastest Olympic sailing class and was the first catamaran to be introduced to the Olympic Games. It was first sailed in the 1976 Olympic Games and saw its last Olympic appearance in 2008.

tornado catamaran building plans

There was not multihull option for sailing at the Olympic Games in 2012, but the Tornado undoubtedly led the way for the current catamaran class, the Nacra 17, which must be sailed with a female and a male member of the crew.

“Sailing the Tornado is where I got the feel for apparent wind sailing. It’s a pretty big cat in the small boat sailing world with its 20ft length and 10ft width creating decent loads and righting moment.

“Also, the Tornado was the only Open discipline at the Olympic Games but it was extremely male dominated.”

Brouwer helmed for Belgium at the 2008 Games, sailing a Tornado catamaran with crew Sébastien Godefroid. “I hope this showed that being a woman you can compete at a high level and be very competitive against men in a mixed gender configuration – just like the great Paul Elvstrøm did sailing with his daughter.”

Tornado catamaran stats rating:

Top speed: 20 knots LOA: 20ft/6.1m Launched: 1967 Berths: 0 Price: £23,000 Adrenalin factor: 70%

Carolijn Brouwer

A three-time Whitbread/Volvo Ocean Race crew, Carolijn Brouwer is also a three-time Olympian. She was born in the Netherlands and represented the country at the 2000 and 2004 Olympics in first the 470, and then the Europe. She then switched to the Tornado, representing Belgium in 2008, when she finished 12th.

If you enjoyed this….

Yachting World is the world’s leading magazine for bluewater cruisers and offshore sailors. Every month we have inspirational adventures and practical features to help you realise your sailing dreams. Build your knowledge with a subscription delivered to your door. See our latest offers and save at least 30% off the cover price.

tornado catamaran building plans

DIY Cruising Catamaran: Complete Building Guide

As an Amazon Associate, we earn from qualifying purchases. We may also earn commissions if you purchase products from other retailers after clicking on a link from our site.

A brand-new cruising catamaran can set you back a hefty amount of money. However, a DIY cruising catamaran provides a more affordable way to own your own boat. While building a large boat can be an extremely challenging and time-consuming experience, nothing beats the pleasure of bringing your own boat to life. 

To build a DIY cruising catamaran, buy good design plans, determine your budget and find a working space. Next, choose your hull material, buy supplies and start building the mast beam. Build and sheathe the hull, install bulkheads, the interior, and finally, launch the catamaran boat.

In this article, you will find a complete guide to building your own catamaran. You will also find detailed information on why you may want to consider building your catamaran and approximately how much this project would cost. Finally, we will explore the advantages and disadvantages of building a catamaran from scratch.

Why You Might Want To Build Your Own Catamaran

Most people might think that purchasing a used boat to repair and fix it up would be cheaper than a DIY cruising catamaran. But while building your own catamaran could be an enormous undertaking, it also comes with many advantages over buying something used. 

Other than the unique opportunity to create beautiful memories and experiences while cruising, sailing, and exploring beautiful coastlines, there are a number of benefits that come along with the DIY approach.  

Knowing Your Boat

Building your own catamaran provides you with intimate knowledge of your boat. You will know every corner, including where to find every bolt, wire, bulkhead, rib, hose, and support as you installed them yourself. This knowledge will enhance your confidence while at sea since you will have entrusted your life to a boat whose history you are aware of and deeply connected to.

Pride of Ownership

The satisfaction you get from crafting something with your own hands is immense. As a result, the knowledge that you built your boat from scratch will fill you with absolute pride and an immense sense of achievement. Furthermore, as an owner-builder, you get to keep and enjoy the boat for as many years as you wish.

Substantial Cost Savings

Building your catamaran will work out cheaper than buying a new or even gently used boat. Though you will likely require some additional labor since doing some things will require an extra pair of hands, if you are particularly good at DIY, you will save a significant amount of money on labor costs as a whole. 

Freedom To Create Your Own Designs

If you decide to buy a catamaran boat, it might not be easy to find one that meets your unique needs. However, instead of choosing from production boats that bear traditional and outdated designs, you can come up with an ultra-modern design or style for your catamaran. You also get to pick your layout, size, and equipment based on your taste and budget.

Great Learning Experience

Building your own boat will help you pick up numerous skills that will come in handy later when sailing your boat. As much as you might still require an expert to help you with specialized skills like carpentry or wiring, your new skills will serve you well. This will also be beneficial when it comes to your boat’s maintenance and fixing things for yourself. 

What To Look For in Catamaran Boat Designs

When deciding on the type of catamaran boat to build, you may want to choose a design that’s simple and easy to build. This is because doing so will allow you to spend a shorter time building the boat. 

You also need to have a set of requirements to guide you in choosing your design or what you might call an ideal cruising catamaran wish list. This is essential because, ultimately, you want to build a boat that offers outstanding qualities such as:

  • Delivers good speed
  • Affordable to own and operate
  • Agile, strong, and easy to maintain
  • Has a high resistance to capsizing
  • Great for sailing and cruising
  • Delivers a comfortable and easy motion underway
  • Good handling ability and high performance under sail
  • User-friendly embarking and disembarking
  • Provides ample living and accommodation space 
  • Presents a reasonable resale value

It’s worth noting that, in general, catamaran boats tend to offer a fair resale value mainly because of scarcity and the high price accorded to production models. So, if you build a well-constructed catamaran, you are bound to get a return that’s much higher than the cost of materials upon resale.

It’s also good to consider whether the design you settle on is from an established designer. This is significant because documentation of the building process is just as valuable when it comes to selling the boat.

How Much Would It Cost To Build Your Own Catamaran?

The cost of building your cruising catamaran will depend heavily on the size of the boat you plan to build and the skills you bring to the table. To give you an idea of probable costs, a professionally built 40 foot (12.1 m) long cruising catamaran could go for up to $300,000. 

Though building it yourself will undoubtedly be cheaper, most DIY boatbuilders tend to underestimate the expected costs. Your final costs should cover not only the cost of material and equipment but also the labor and time it would take to come up with the final product. 

If you were to build a 40-foot (12.1-meter) catamaran, your cost of materials would range between 20-30% of the total cost. Therefore, for $300,000 total, the boat’s materials would range between $60,000 and $90,000. The hull tends to range between 15-35% of the total build. Again, this depends on the finish and furniture.

But before you even start working on the DIY project, you will need to figure out where to do the work. If your home has ample space, then you can opt for a backyard building. But if you live in a small apartment, then you might want to consider renting a small garage at first and then move on to a boatyard later. This is one of the significant costs involved in building your multi-haul.  

What You Will Need

To get a clearer picture of how much the entire project would cost, let’s have a look at what else you will need to purchase.

  • Good design plans
  • Working space
  • Ground tackle
  • Matting and roving
  • Equipment such as the engine, windows, rudders, deck fittings, mast, and rigging

In addition to the above, you also need to install plumbing and electricals. You may also want to consider going electric rather than using diesel. Not only will this drastically reduce your maintenance costs, but you get to use the regenerated power for all of your housing needs while sailing. 

Some catamaran boat designs help you save costs by advocating the use of less expensive corpus materials. Most of the material goes directly into making the boat, which means there is hardly any wastage on vacuum bagging . With this method, there are few molds and temporal building forms and fewer fillers to grind off as waste. All these factors reduce the time and cost it takes to build your catamaran boat.

That said, building a boat of any kind is a huge financial undertaking. As such, you still need to have the financial ability to keep building; otherwise, your project will stall or take much longer than anticipated. Instead of enjoying yourself and making memories cruising to faraway lands, you might end up spending all your time building a seemingly never-ending boat.

To reiterate, this project is more of a labor of love, given that it involves a tremendous amount of manual work. Calculating an hourly rate on the time spent building the boat and adding this cost to that of materials may make it seem a very pricey exercise. However, it is vital to understand that your time matters, and every hour you spend working for “free” should be included. 

With that in mind, you need to ensure that you are fully devoted to the boat construction project and are sure you want to do it before you begin. Stopping halfway because it seems like too much work would be incredibly costly.

How To Build a Catamaran

When it comes to building a cruising catamaran, you have 3 main options:

  • You can buy an old boat and refurbish it.
  • Purchase a bare hull plus deck molding for a home-boat building.
  • Start from scratch and build everything, including the hull, on your own. 

As mentioned above, renovating an existing boat may end up being more costly than starting from scratch. To build a catamaran boat from scratch, follow the below step-by-step guide.

Prepare the Essentials

Before you jump into such a large project, there are several important aspects to consider:

  • Buy your plans from an established catamaran designer. You can also get inexpensive, easy-to-build catamaran designs online.
  • Get access to a large working space or build a shed . Depending on your climate, you may need to opt for climate control to avoid an excess of moisture in humid areas. 
  • Decide on your choice of hull material. This could be fiberglass, aluminum, steel, wood, or ferroconcrete. 
  • Start working on a bill of materials estimate. Include everything that you think you need to get a better idea of the initial costs.

Build the Mast Beam

Using wood and epoxy, cut and glue together the pieces of wood that will form the mast beam. Most of the work at this stage can occur in a garage since it involves building small parts. Still, the work could take up to 4 months, so be prepared to put in long hours.

Build the Boat Hull

Now, it’s time to build the boat’s hull. A catamaran comprises two hulls which are connected with a deck. Below is a short video showing how to build a hull mold:

This work requires a larger facility, so you might need to move out of the garage and into a boatyard. If you don’t have access to a larger workshop, consider building a shed where you can work as you do the construction. Make sure there’s enough room to fit the boat and also allow you to work comfortably. To cover the shed, you can use opaque white tarps. 

Sheathe the Hull

Get all the materials you require for this stage in the construction, such as lots of resin, fiberglass, and foam for use in the hull cores. You’ll also require matting and glass roving to sheath the hull . 

Sheathing helps to make the hull impervious to water and other marine borers. But first, you need to prepare the hull using a rotary sander. To make it as smooth as possible, use light, sweeping strokes. This is a very dusty task so be prepared to wear a facemask and safety goggles. 

Install the Bulkheads

Next is installing the plywood bulkheads . You might need to call in friends to help turn the hulls or use a crane. In this step, you will need to laminate the hull sides on the molded hull panels and bond them above the bulkheads. Ensure the bulkheads are snug and sealed in place.

Construct the Interior Structure

Over the next couple of months, the boat work will involve joining the hulls together with the beams that you had made back in the garage. Then, install the cuddy cabin, decks , and the cockpit . Soon the boat will start to take the shape of a catamaran.

Next, proceed to construct the major structural components such as stairs, hatches, mini-keels, and the interior. Then comes the work of fairing the boat, which is quite labor-intensive. 

Finally, it’s time to apply primer on the catamaran boat and start the paintwork. Before painting the boat, you will need to do additional sanding to finish off the two layers of primer as well as fill all the pinholes. Since it’s a large boat, the catamaran has lots of surface area; thus, the sanding could get extremely exhausting—mentally and physically—at this point.

The painting can take a while, too. The hulls are the easiest to paint, but the topsides, non-skid, as well as masking and prepping could seem never-ending. 

The final stretch involves working on the center bridge deck cabin and other final touches like installing the engines, electricals, and plumbing. This is also the time to fix the rudders, rigging, mast, windows, and deck fittings.

Launch Your Cruising Catamaran

After many months or years of hard work, your cruising catamaran is finally ready to test the waters. After lowering the boat into the water, check carefully in case there are leaks. If none, you can set up the sails and take your catamaran out for your first cruise. 

Below is a short video that takes you through the entire boat-building process:

If you don’t have deep pockets, don’t despair. It’s also possible to build an inexpensive catamaran boat, as shown in this post from the coastal passage .

The Pros of Building a Catamaran

Though it will be a costly endeavor, there are so many things to look forward to should you decide to build your own catamaran:

  • It can be lots of fun.
  • You get to have a new boat.
  • It’s an excellent hobby for DIY enthusiasts.
  • The effort is rewarding.
  • It offers a great learning experience.
  • You get the exact kind of boat you want.
  • You can alter building plans and tailor the boat to suit your specific needs.
  • It might be cheaper than buying a new boat.

The Cons of Building a Catamaran

Though there are a number of positive aspects to a DIY build, it is just as important to keep in mind that it won’t always be easy:

  • Maintenance costs can be quite high.
  • It’s both mentally and physically exhausting.
  • It might require some technical know-how.
  • It can take many months or even years to complete.
  • It requires a lot of commitment to finish the DIY project.
  • It might be challenging as well as expensive to get insurance.  
  • You will spend almost all your free time building the boat. 

DIY Cruising Catamaran Tips and Tricks

If you are new to boat building, it would be a good idea to build a small boat first. This would give you a good indication as to whether you’d enjoy tackling a more extensive project like building a catamaran. Again, if you are the handy type, fixing your own electronics could also save you a significant amount of money. 

Here are more tips and tricks to get the most out of your DIY cruising catamaran:

  • Lower your costs. Bring down your costs even further by sourcing for parts and supplies at marine surplus outlets, Craigslist, eBay, or wholesale suppliers. 
  • Enhance your resale value. Most home-built boats are not easy to sell since they tend to be too customized. To enhance your resale value, it’s advisable to work with a standard design from a well-established naval architect.
  • Follow the design instructions. Make sure to follow the designer’s instructions regarding the type of materials and tools to use during the build to avoid making costly mistakes.
  • Maintain your original budget. Avoid any additional customizations once you have started building the boat. Using good plans and sticking to them ensures that your budget doesn’t spiral out of control.

Final Thoughts

Building a catamaran is about more than saving money. It’s fun, exciting, fulfilling, and can be a great learning experience. While it might take many months of back-breaking work, comparative shopping and sourcing for materials will help you save a lot of money. Still, at the end of it all, you’ll have a beautiful catamaran boat, all ready for your first cruising adventure.

However, if you have neither the time nor the energy to build your own catamaran from scratch, refurbishing an existing hull might prove faster and easier. It also works out much cheaper than buying a new boat.

Owner of CatamaranFreedom.com. A minimalist that has lived in a caravan in Sweden, 35ft Monohull in the Bahamas, and right now in his self-built Van. He just started the next adventure, to circumnavigate the world on a Catamaran!

One thought on “ DIY Cruising Catamaran: Complete Building Guide ”

Hello, I am a French Quebecer who is original, imaginative, creative and who finds that all boats and catamarans have a huge flaw and a very big lack of logic. I would have a brand new concept…. I am sending this message to any catamaran creator – designer to make those who have the opportunity and the intelligence to want to know about my innovative idea which will finally upset the market much richer. An idea that will totally change the concept of sailing, navigation and save so much worry!! All I would ask for is a small percentage of each sale of the new product. To be able to make me produce one when I have enough!! It is certain that like that, you just want to tell me: come on Mr. Lessard give us your idea but do not take your word to help me in return! But, if you are the kind of man to have only one word and maybe have a proof of your good faith if the realization of the project would make it… I will be very happy!! Giving it to everyone wouldn’t bother me either…. all I would like is to be able to find flax fiber (too expensive carbon) to be able to try to make my catamaran myself. Because not rich! Have a nice day and looking forward to having a message!!

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Save my name and email in this browser for the next time I comment.

Recent Posts

Must-Have Boat Gear for Catamaran Sailors!

Sailing is probably the most gear-intensive activity I've ever done; there are so many decisions to be made about what gear to buy now, for tomorrow, and what to definitely never buy. The gear on...

6 Best Trailerable Trimarans For Bluewater and Coastal Sailing

Having a boat costs a lot of money, even when you are not using it, marina fees, etc. And once it is in the water most sailors never go very far from their "home marina" and sailing will be somewhat...

tornado catamaran building plans

tornado catamaran building plans

Register Log In Tornado Plans
Previous Thread
Next Thread
Print Thread
Rate Thread
Hop To
Page 1 of 4 1 2 3 4

02/09/04 04:13 AM
02/09/04 04:13 AM
Joined: Apr 2003
Posts: 1,669

Pooh-Bah
 
Pooh-Bah

Joined: Apr 2003
Posts: 1,669

-- Have You Seen This? --
[ ]
02/09/04 10:44 AM
02/09/04 10:44 AM
Joined: Jun 2001
Posts: 778
 
Joined: Jun 2001
Posts: 778

[ ]
02/09/04 11:16 AM
02/09/04 11:16 AM
Joined: Nov 2002
Posts: 612
 
Joined: Nov 2002
Posts: 612

[ ]
02/10/04 09:51 AM
02/10/04 09:51 AM
Joined: Feb 2004
Posts: 3,528
 
Carpal Tunnel

Joined: Feb 2004
Posts: 3,528


Scale up will not get you a class legal boat. Hull tolerances are quite tight on the Tornado.

[ ]
02/10/04 11:53 AM
02/10/04 11:53 AM
Joined: Nov 2002
Posts: 612
 
Joined: Nov 2002
Posts: 612

[ ]
02/10/04 02:28 PM
02/10/04 02:28 PM
Joined: May 2003
Posts: 4,451
 
Joined: May 2003
Posts: 4,451

[ ]
02/10/04 03:42 PM
02/10/04 03:42 PM
Joined: Jun 2001
Posts: 1,449
 
Joined: Jun 2001
Posts: 1,449

[ ]
02/10/04 09:03 PM
02/10/04 09:03 PM
Joined: Jul 2001
Posts: 1,200
 
Joined: Jul 2001
Posts: 1,200

[ ]
02/13/04 11:13 AM
02/13/04 11:13 AM
Joined: Jun 2001
Posts: 778
 
Joined: Jun 2001
Posts: 778

[ ]
02/13/04 01:49 PM
02/13/04 01:49 PM
Joined: May 2003
Posts: 4,451
 
Joined: May 2003
Posts: 4,451


I dont think strip planking is a good way to build a Tornado. You will get to many horizontal glue joints that adds a lot of weight. At least that was what Farrier discovered when he started to use vertical joints between foam sheets.

I really liked the Gougeon system used as internal stiffening. Building out of plywood is easy, but I'm afraid the panel stiffness would not be very good.. Perhaps the Taipan builders can correct med ?

If plywood boats was good, why did the Gougeons use cold moulding ?

I looked into how to get the hull lines for the Tornado, and found some interresting things.
1: Measurement of the hulls are very detailed, not much room for error if home building/designing.
2: Measurement blanks costs £ 800 !!! (I know where I can source som old ones for free, but..)
3: Marstrøm, Yves Louday/Reg White are launching new models with new hull shapes. Basically they have made the hulls slimmer in front and less bouyant at the stern.


[ ]
02/13/04 05:09 PM
02/13/04 05:09 PM
Joined: Feb 2004
Posts: 26
 
Joined: Feb 2004
Posts: 26

[ ]
02/13/04 07:25 PM
02/13/04 07:25 PM
Joined: Jun 2001
Posts: 1,449
 
Joined: Jun 2001
Posts: 1,449

[ ]
02/15/04 12:16 AM
02/15/04 12:16 AM
Joined: Jun 2001
Posts: 778
 
Joined: Jun 2001
Posts: 778

[ ]
02/15/04 07:56 AM
02/15/04 07:56 AM
Joined: May 2003
Posts: 4,451
 
Joined: May 2003
Posts: 4,451

[ ]
02/16/04 11:14 AM
02/16/04 11:14 AM
Joined: May 2002
Posts: 3,114
 
Joined: May 2002
Posts: 3,114

[ ]
02/17/04 01:26 AM
02/17/04 01:26 AM
Joined: Apr 2003
Posts: 1,669

Pooh-Bah
 
Pooh-Bah

Joined: Apr 2003
Posts: 1,669

[ ]
02/17/04 09:51 AM
02/17/04 09:51 AM
Joined: May 2002
Posts: 3,114
 
Joined: May 2002
Posts: 3,114

[ ]
02/17/04 10:35 AM
02/17/04 10:35 AM
Joined: Jun 2001
Posts: 778
 
Joined: Jun 2001
Posts: 778

[ ]
02/17/04 04:33 PM
02/17/04 04:33 PM
Joined: Dec 2001
Posts: 5,590
 
Joined: Dec 2001
Posts: 5,590

[ ]
02/17/04 05:57 PM
02/17/04 05:57 PM
Joined: May 2002
Posts: 3,114
 
Joined: May 2002
Posts: 3,114

Announcements
General Sailing Forum
Junior/Youth Sailors Forum
Home Built Boat Building
Politics, Religion, and Trolling
A-Cat Forum
Hobie 16 Forum
Inflatable Sailboats Forum
Mosquito Catamarans
Shark Catamarans
F16 Forum
F18 Forum
F20 Forum
Solo Sailors Forum
Cruising Multihull Forum
Folding Trimaran Forum
F14 Forum
F12 Forum
Lake Michigan Region - CRAW / CRAM
CABB (Catamaran Assn. of Biscayne Bay)
Delray Catsailors Yacht Club
IRCA (Indian River Catamaran Assn)
TBCS (Tampa Bay Catamaran Sailors)
Hawaii Hobie Cat Association (HHCA)
Long Island Cat Sailing
IWCA (International Wave Class Association)
View Profile
Send Private Message
Follow User
Show Forum Posts
View Profile
Send Private Message
View Homepage
Follow User
Show Forum Posts
Search
0 registered members (), 186 guests, and 149 spiders.
Admin, Global Mod, Mod
Newest Members
, , , ,
8150 Registered Users
Top Posters(30 Days)
Forum Statistics
--Advertisement--
· ·
 |   |   |   |   | 

BUILD YOUR RAKU CAT WITH A DuFLEX KIT BY FOLLOWING THESE NINE BASIC STEPS

Duflex Kit Construction Step.1

Step 1. Kit Design

Work with us to finalise the details of the design you have chosen including any design options or additional modules to be included in the kit.

We will determine the laminates, the number of panels required for each laminate, create the cutting files and prepare a quote for the kit if it is not already priced.

Once the design details and pricing are confirmed you are ready to place your order.

Duflex kit construction Kit image-01

Step 2. Unpacking

2. The kit arrives at your workshop door, usually by container, as a stack of 1.2m x 2.4m routed composite panels ready to be joined. The shipment will normally include additional reinforcements, resins, and ancilary products as specified.

Unpack the shipment and stack the panels out of the way of the space where the panels will be joined.

If you have purchased a joined kit many of the panels will already be joined up to the length that can be shipped in a container (12m).

Duflex Kit Construction Step 2 image-02

Step 3 Joining the Panels

Set up the work space where the panels are to be joined.

The panels have a scarf join called a Z join that facilitate the join without needing tapes.

The joining can be done with a heated Z press that cures the epoxy join quickly. Alternatively they can be joined with clamping pressure.

If the panel are are being joined with the Z press you will need an elevated work bench the full length of the longest panels you are using. (image below).

If you are joining them with a clamping technique the space can be on the factory floor.

A nesting booklet is provided with the kit to show how the panels are joined (right)

Duflex kit construction Step 3 image-01

Joining the panels with  clamping pressure

tornado catamaran building plans

Panels are being joined into a single long panel by painting the surfaces of the scarf join with epoxy screwing through plywood battens that have a release film applied to one side.

Joining the panels with the Z Press

tornado catamaran building plans

Step 4 Stacking Joined Panels

Once the joins are cured the panels are stacked to one side until they are needed for the job. The inividual parts should not be cut free of the panels until they are required.

Bulkhead and floor panels will be needed before the hull sides and cabin top so they should be left to the front of the stack wherever possible.

Diuflex Kit Construction Header image step 5.

Step 5. Separating the Parts

When assembly is ready to begin the individual parts are separated from the panels by cutting the joining tabs. It is likely you will be building onto moulded hull bottoms that have been built from strip planking or another method of building moulded components. The process for building moulded components is described in another article.

Duflex kit Construction Step 5 Image-01

Step 6. ASSEMBLY

As the joined panels are assembled onto the job you will need to apply glass tapes to the joins as specified in your plans.

Panels can be surfaced and coated inside and out with high build while they are on the workshop floor to minimise fairing time once they are assembled to the boat. The paint on the panels shown here has been kept back from the edges to provide a good bond for the tapes.

Duflex Kit Construction Assembly image-01

Smaller items such as steps, seats and dagger cases are nested into the kit and for the more complex parts diagrams are provided to assist with the assembly process.

Duflex Kit Construction Header Image Step 7

Step 7. Interior

Interior kits can be ordered with the primary kit, or they can be ordered later when final decisions have been made about the interior arrangement.

A compromise solution is to order the interior as a set of plain planels that can be cut to shape on site after finalising the layout.

Duflex Kit Construction Step 7 Image 2

Step 8 Fairing, Painting, Hardware Installation

8. The DuFLEX construction process goes a long way to minising the amount of fairing that has to be done, but inevitably any boat that has not come out of a female mould will require some level of fairing and surface preparation prior to painting. 

The fillers and resin systems required for the fairing work are normally supplied as part of the kit.

Hardware installation is the same as for any other form of construction using high density core inserts or consolidated laminate in way of fittings.

Duflex Kit Construction Step 8 Image 2

Step 9. Sailing

Go Sailing. This Barefoot 40 Catamaran was built entirely with a Duflex kit in Foam/Glass and Epoxy resin systems from ATL Composites

tornado catamaran building plans

DuFLEX Kits are manufactured and supplied world wide by ATL Composites

atlcomposites.com.au

And in Europe by VDL Composites

www.vonderlinden.de/her/28/vdL-Composites-GmbH

For more information on DuFLEX and associated Products 

atlcomposites.com.au/category/27/DuFLEX

tornado catamaran building plans

Join the Newsletter

Custom and Racing Designs

  • Scroll to top

Log in or Sign up

You are using an out of date browser. It may not display this or other websites correctly. You should upgrade or use an alternative browser .

Small trimaran with Tornado/Nacra 5.8 center hull

Discussion in ' Multihulls ' started by revintage , Dec 25, 2021 .

revintage

revintage Senior Member

Got the idea to make use of some of my beachcat parts and planning a trimaran project to be sailed 2023. Will use an old Panthercraft Tornado hull as aka and a pair of fresh Nacra 5.5 hulls as akas. Length 6.1m, beam 4.5m with upwind SA 22.35 sqm. The Tornado hull is the one to be modified as it is in bad shape and anyway needs to be reinforced and repaired. The Nara hulls must not be modified at all. Rudder on center hull and daggerboards in the Nacras. The main beam pockets on all three hulls will be used inline and the center rear pocket will be moved 15cm forward to line up with the Nacra hulls. All hulls has the same height at the main beam pocket. Image shows the hulls lined up around the main beam and to scale. Question is, how should the amas be placed heightwise in relation to the aka and also if the amas eventually should be rotated somewhat bows up?  

Doug Halsey

Doug Halsey Senior Member

A good starting point would be to raise the amas up (without rotating) until they are just barely clear of the fully-loaded waterline at 0° heel angle. That way you will never be dragging the windward hull around while sailing. I suspect that once you have gone through that exercise, you will conclude that your total weight is excessive and the aka will be too deeply immersed. I considered building something along those lines back in the middle 80's after I was given most of an old abandoned Tornado, but decided the aka was heavier than I could easily manage by myself for assembling & disassembling on the beach.  
Thanks Doug, Taking your advice in account, it ends up in a quite high adjusted DWL, together with a rather odd looking creature. As my idea is to use a dolphinstriker on the main beam the one with straight beams is my option. When using daggerboards, this will probably also be the one to go for.  
This would be the case with the hulls level. Maybe place the akas 10 cm higher, or no at all, instead of 25cm? This would make things so much easier on the practical side. Question is if it is worth the effort to place the akas higher in a suboptimal design? This is anyway something I had fantasies about, to use at the lake house, to be used together with family members, to make them understand the beauty of multihull sailing .  

Corley

Corley epoxy coated

I like the idea but can't help but think the 5.5 hulls may be too heavy for a performance boat as floats. The tornado main hull is reasonably light on displacement now consider you are adding say 120kg? for hull weights for the 5.5. Yes some will say the floats will carry some displacement which they do but once your windward float is levered out it's weight is effectively added to your displacement I'd look at buying Kurt Hughes TMS20 trimaran stock plans and building his floats or just contact him and see if he would sell you just the float design pages. I'm sure they would be lighter and more suitable than 5.5 hulls and just use the Tornado main hull centreboard for lateral resistance. If you consider your illustration of the heeled waterline the weight of the windward hull will be depressing the centre hull unless the 5.5 hull has enough displacement to lever the main hull out as you are hanging 50kg to windward. I think subtleties in terms of weight matter alot at this size and could be the difference between an acceptably performing or poor performing boat. The displacement is going to be tough to get right the Kurt Hughes design has about 400kg of displacement and weighs about 200kg which sounds about right. You add a bit of weight with beach cat hulls as they are designed for beach abuse and have daggerboard cases fitted which is imo parasitic weight on a simple boat. Kurt Hughes Multihull Design - Catamarans and Trimarans for Cruising and Charter http://www.multihulldesigns.com/designs_stock/daysail/20_tri.htm  

oldmulti

oldmulti Senior Member

Revintage. Another approach may be to use the Nacra hulls with a purpose built main hull. This will allow the float position to be pushed forward moving the float center of buoyancy to be ahead of the main hull center of buoyancy allowing more power reaching etc. Also the crossbeam positions are not controlled by the main hull crossbeam slots. If you are going to have to repair the Tornado main hull it may be simpler to build a new one. Just a suggestion.  
Thanks for your advices, Corley and oldmulti. I am building this the year after next, from leftovers in my stash, two other projects to finish before this one. Have rig, sails(selftacking jib and asymmetric), hulls, aluminium tubing for beams, and every small part needed. Will not invest in any new items, only epoxy, glass and carbon to adapt and repair the crappy center hull. As earlier mentioned, it will only be used at my lake house with flat water and in winds below 20 knots. I imagine it could be a good ride single handed. So this is just about combining the items in the best way possible. The Tornado hull could absolutely be moved rearwards if that helps. One could also look at the imagined tri, as a Nacra 5.5 widened to 4.5m instead of 2.6m but with a higher rig and a few more sqm SA and added stability due to the center hull. The added weight will not be more 60kg and no trapezes will be needed.  
Keep us up to date, I'd love to see how your project progresses.  
Thanks Corley! Plenty of time to plan, as I at the moment am fully occupied getting my "Aerow" foiler project ready this spring. Checked out Kurt Hughes site and got the idea to add a "sea-sole" as on the 16" daysailer, though. Will come back and try new ideas on you.  

Attached Files:

Seasole.png.

Maybe a little to far out, but I was recently offered a pair of skeg hulls for the former ISAF Youth catamaran Sirena/Nacra SL 16 at a very low price. I checked them and they where no beauties but very stiff, estimated the weight to 35-40kg. By using them, I could keep the widened 5.5 platform almost intact and only borrow the F18 rig from it. No daggerbords to break, but maybe an optional T-centerboard? Very low bouyancy bows, though. How lousy would these hulls be for a mini, leisure tri?  

Russell Brown

Russell Brown Senior Member

The original Tremolino used Hobie 16 hulls for ama's and a Hobie 16 rig. Have you sailed on one? I think it's a remarkable sailboat and very hard to beat with a Hobie 16, so I'd say those hulls could work fine as ama's. Being shorter, they would put less load on the connective structure than longer hulls. I don't know about drag from the skegs.  
Thanks for all info. About the Tremolino they seem to have a large aka daggerboard. My idea, but probably a little to optimistic, was to get rid of the daggerboard. Anyway I have been Google researching and also remember what oldmulti said. I guess the akas ideally should be moved to have all sterns at close to the same line. Should look like this, where I have aligned the beginning of the waterline, if I have understood it right?  
Revintage. Aligning the bows at the waterlines should work to allow more float buoyancy forward for better reaching etc. The Nacra 5.5 hulls would be faster but I can understand not wanting dagger boards on a fun trimaran. This could be a real fun project.  

upchurchmr

upchurchmr Senior Member

Use a centerboard or dagger board on the main hull I once was sailing a Tornado (old/ well used) in light wind against Hobie16's (to weather). Easily outsailing them, then they started pulling up to me. Found that one of 2 centerboards had floated up. With one board instead of two, the Hobie 16s were beating me. Align the stems, raise the ama's above the water when setting idle. Have fun. What is your proposed beam? Do you intend to be able to sail with the main hull out of the water? Higher wind speed. If you are extensively repairing the Tornado hull, consider adding 1/2"+ of foam and glassing to get increased volume in the hull. I know you said no extras, but....... You might calculate the volume of the Nacra hulls, decide what you need to fly the main hull, then decide if you could shorten the height of the amas to get the volume you need, with less weight. When repairing the tornado hull, check to see if the foam in the deck is waterlogged. I destroyed a hull, thinking it was extensively delaminated. The only area that had an issue was the deck where fittings were bolted in. The foam was not sealed well from the factory where fittings were bolted into the deck. I wasted an almost perfect set of hulls. Which could have been repaired - for casual sailing.  
  • Advertisement:

trip the light fandango

trip the light fandango Senior Member

I would be tempted to make the centre hull wider by cutting it down the middle and adding a fine wedge shape. good luck, interesting project.  

Tiny Turnip

Unstayed mast build for small canoe based trimaran.

eiasu

Which small trimaran for cruising/charter

FantasyTrimaran

Your thoughts on this small trimaran?

JunkRat

Want to engineer a small solar powered trimaran. Seeking advice.

rapscallion

foiling small trimaran

neptunkryssare

Want to build a small foiling trimaran

Doug Lord

Small Surface Piercing Trimaran Foiler

buzzman

Small trimaran / microcruiser

joz

Heeling Angles for Small Trimarans Under 20’ 0” LOA

smallyachtsailr

Small trimaran ama angle?

  • No, create an account now.
  • Yes, my password is:
  • Forgot your password?

Boat Design Net

Deck fittings for boats

Wednesday, december 2, 2020, wooden tornado catamaran building plans.

New builder from Kuwait looking for help & tip - Boat

Hi I know you come here to see wooden tornado catamaran building plans An appropriate destination for certain i will demonstrate to back to you I know too lot user searching The information avaliable here Honestly I also like the same topic with you Information is you need wooden tornado catamaran building plans Hopefully this review pays to back, right now there still a lot knowledge right from word wide webit is possible to while using the Slideshare place the important thing wooden tornado catamaran building plans you can observed lots of articles to sort it out

No comments:

Post a comment.

Web Analytics Made Easy - StatCounter

COMMENTS

  1. Tornado Catamaran Building Instructions From 1979

    It was originally designed so that it could be home-built by individuals. Each hull is made from two pieces of plywood glued together in a vee shape position, then forced into a jig that bends them into a gracefully curved hull. The technique is called "tortured plywood". These are the detailed building instructions from Houlton Boat Company 1979.

  2. Tornado Building Plans :: Catamaran Sailboats at TheBeachcats.com

    Download These Tornado Building Plans. These descriptions were originally intended to be used together with the ITA/ISAF issued plans, but it is quite straightforward to build a boat without the ITA/ISAF plan sets. Jerry Houlton stopped building Tornados a long time ago, but these plans lived on thanks to Tornado afficiando Kevin Cook in the USA.

  3. Catamaran Sailboats at TheBeachcats.com

    Wooden Tornado Catamaran Building Plans. Description: This is a .zip file containing plans and instructions for building a Tornado Catamaran of your own. Included in the package are 39 high-res images of building drawings and a .pdf file with 32 pages of detailed building instructions. This is a 16.8mb download, so you might want to browse ...

  4. Tornado Building Plans

    Jerry Houlton stopped building Tornados a long time ago, but these plans lived on thanks to Tornado afficiando Kevin Cook in the USA. Kevin has continously supplied amateur Tornado builders with plans, in a non-profit attempt to keep the wooden Tornado alive. It was trough Kevin the plans used for digitizing was sourced, during christmas 2004.

  5. How to (with pictures) build a Mosquito catamaran in tortured ply

    Might be a good reference for someone who wants to build a tortured ply catamaran be it a mosquito, tornado or A class. The attachment has some tortured ply plans for an early A class. There are also plans for "Houlton" tornado in tortured ply available on the web. The Gougeon Brothers on Boat Construction also has a section on tortured ply ...

  6. How long does it take to build a Tornado Catamaran

    Here's the process of assembling the Tornado Catamaran:1: Beams on and tighten bolts2: Fit trampoline, lace and tighten 3: Position mast and bowsprit3: Attac...

  7. Tornado catamaran how to assemble, How to build

    ☞ SUPPORT JOYRIDER TV⛵️Channel Membership https://www.youtube.com/channel/UC1lH...⛵️Patreon https://www.patreon.com/joseph_bennett ⛵️Getting a T-shirt ...

  8. Catamaran Build

    The goal is to build a motor catamaran. Hopefully it will be electric. Currently we are following the guide for the Tornado catamaran hulls.The plans can be ...

  9. Tornado Catamaran

    1966. Tornado Catamaran is a 6.1 m catamaran sailboat designed by Reg White and Rodney March and built by Sailcraft Ltd., Marstrom Composite AB, and Windrush Yachts starting in 1966. Designers. Reg White. Rodney March.

  10. Construction Methods

    The most famous use of tortured ply is probably its original use to construct hulls for the lightweight 'Tornado' catamaran. In 1979, using 4.5mm ply for the hulls, she outperformed all the other B-class competition, to then be selected as a new Olympic Class - still raced today. Although the method is still used by some today, the actual ...

  11. TORNADO CATAMARAN

    The TORNADO first appeared as winner of the 1967 international "B" class catamaran trials. It was an Olympic class from 1976-2008. The class rules were changed to allow twin trapezes, 'flat head' mainsail, and asym. spinnaker.(2004?)

  12. Tornado (sailboat)

    The Tornado is a double handed multihull class recognised as an International Class by the International Sailing Federation. It was used for the Catamaran discipline at the Olympic Games from 1976 to 2008. Design One hull flying. The boat was designed in 1967 by Rodney March from the Isle of Sheppey, England.

  13. History

    1997-2003A Brief Tornado History. The Tornado was designed in the autumn of 1967 by Rodney March from England, with help from Terry Pierce, and Reg White, specifically for the purpose of being the new Olympic Catamaran, which was to be selected by the IYRU in an Olympic Catamaran Trials. The boat was developed mainly in Brightlingsea, England.

  14. World's coolest yachts: Tornado catamaran

    The Tornado catamaran was for many years the fastest Olympic sailing class and was the first catamaran to be introduced to the Olympic Games. It was first sailed in the 1976 Olympic Games and saw ...

  15. DIY Cruising Catamaran: Complete Building Guide

    If you were to build a 40-foot (12.1-meter) catamaran, your cost of materials would range between 20-30% of the total cost. Therefore, for $300,000 total, the boat's materials would range between $60,000 and $90,000. The hull tends to range between 15-35% of the total build.

  16. Where to find Tornado plans

    Yes, these are few and far between...I've never seen a set of the templates, this despite being the son of one of the guys that ran the SailCraft of Canada Tornado manufacter. I believe there was a posting on this site a few onths back from Kevin Hill.

  17. Tornado Plans

    Does anybody know where I can obtain plans to build a Tornado. I have a guy in OZ that wishes to build a wooden spinnaker Tornado. (his 3rd). Thanks

  18. Catamaran Construction with a DuFlex Kit

    Step 1. Kit Design. Work with us to finalise the details of the design you have chosen including any design options or additional modules to be included in the kit. We will determine the laminates, the number of panels required for each laminate, create the cutting files and prepare a quote for the kit if it is not already priced.

  19. Tornado Catamaran Building Instructions From 1979

    Feb 10, 2014 - Tornado Catamaran Building Instructions From 1979: The Tornado is the catamaran raced in the olympics.It was originally designed so that it could be home-built by individuals.Each hull is made from two pieces of plywood glued together in a vee shape position, then forced into a jig that bends them i…

  20. Small trimaran with Tornado/Nacra 5.8 center hull

    Will use an old Panthercraft Tornado hull as aka and a pair of fresh Nacra 5.5 hulls as akas. Length 6.1m, beam 4.5m with upwind SA 22.35 sqm. The Tornado hull is the one to be modified as it is in bad shape and anyway needs to be reinforced and repaired. The Nara hulls must not be modified at all. Rudder on center hull and daggerboards in the ...

  21. PDF Tornado Catamaran Building Instructions

    boat plans, Atkin Pic Example Free tornado catamaran plans Tornado Catamaran Drawings A. racing the old Olympic catamaran, the Tornado, and has coached Extreme Sailing The boats are as identical as it's possible to build them, and so they make a on the race course with instructions to go a particular way," says Macbeth. Tornado catamaran ,

  22. wooden tornado catamaran building plans

    Now wooden tornado catamaran building plans is incredibly common as well as all of us think various several months coming Below is known as a modest excerpt an important theme connected with this data. By romanda at December 02, 2020. Email This BlogThis! Share to Twitter Share to Facebook Share to Pinterest.