homemade catamaran boat

DIY Cruising Catamaran: Complete Building Guide

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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!!

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How to Build a Catamaran Boat? (Step-by-Step Guide)

Building a catamaran boat from scratch is a rewarding and challenging endeavor.

It takes a combination of skill, dedication, and hard work to craft a seaworthy vessel.

In this step-by-step guide, you’ll learn how to design and size your catamaran, gather the necessary materials, cut and assemble the pieces, lay fiberglass and apply epoxy, make finishing touches, add hardware and paint, and rig the boat.

With the right tools, planning, and patience, you can make your dream of sailing in a catamaran a reality.

Table of Contents

Short Answer

Building a catamaran boat requires a lot of patience and skill.

The first step is to choose the right materials for the hull, such as fiberglass, wood or aluminum.

Then, you will need to build the frame of the boat, which includes the crossbeams and the main hull.

After that, you will need to install the decking, the rigging, and other components.

Finally, you will need to paint and varnish the boat, as well as install the outboard motor and other accessories.

Design & Size Considerations

When it comes to building a catamaran boat from scratch, the first step is to determine the design and size of the boat.

This should take into account the intended use of the boat, such as sailing, fishing, or leisurely cruising.

The size of the boat will depend on the number of passengers and the type of activities the boat will be used for.

For instance, a larger boat may be needed if passengers will be standing or participating in watersports.

The design of the boat is also important and should be chosen based on the intended use.

If you are looking to build a sailboat, you will need a design that is optimized for sailing.

On the other hand, if you are looking to build a fishing boat, you will need a design that is optimized for fishing.

There are a wide variety of boat designs available, so it is important to research and choose the one that best suits your needs.

In addition to the design and size, you will also need to consider the materials used for construction.

The most common materials for building a catamaran boat are wood, fiberglass, and epoxy.

Each material has its own advantages and disadvantages, so it is important to research them and determine which one is best for your project.

Finally, you will need to consider the cost of the project.

Building a catamaran boat from scratch can be a costly endeavor, so it is important to have a budget in mind before you begin.

The cost will depend on the type of materials used and the complexity of the design.

It is also important to factor in the cost of any tools that may be needed for the project.

By taking into account the design and size, materials, and cost of the project, you can be sure to build a catamaran boat that meets your needs and budget.

With the right amount of patience and attention to detail, you can build your own catamaran boat in no time.

Gathering Materials

Gathering the materials needed to build a catamaran boat from scratch can be a daunting task, but it is essential for creating a sturdy and safe vessel.

Before starting the building process, it is important to have an accurate and detailed plan for the boats design and size.

Once a plan is in place, it is time to begin sourcing the necessary materials.

The most common materials used to construct a catamaran boat are wood, fiberglass, and epoxy.

When choosing wood, it is best to select a species of timber that is strong and durable, such as mahogany, teak, or cedar.

Additionally, the wood should be clear and free of knots, splits, and other defects.

Fiberglass is a lightweight fabric that is resistant to water and provides additional strength to the boats hull.

Epoxy is a waterproof adhesive that is used to seal the boat and ensure that it is watertight.

It is important to ensure that the materials are of high quality, as this will help to ensure the boats longevity.

Additionally, it is important to purchase the necessary materials in the correct amount and size.

Too little or too much of a material can be a costly and time-consuming mistake.

Finally, it is important to keep any leftover materials for future repairs or modifications.

With the right materials gathered, the next step is to cut the wood and begin the assembly process.

Cutting & Assembly

Cutting and assembly are the most important steps when it comes to building a catamaran boat from scratch.

The first step is to decide the design and size of the boat.

This will determine the type of materials you need to gather and the amount of effort that needs to be put into the project.

After deciding on the design and size, you will need to cut the wood to fit the design.

This includes cutting the wood to the desired size, as well as cutting any additional pieces that may be needed to complete the design.

It is important to ensure that all the pieces fit together correctly and securely, as any mistakes could lead to a weak boat.

Once the wood has been cut, it is time to assemble the pieces together.

This involves attaching the pieces together with glue, screws, and nails, and ensuring that the pieces fit together securely.

It is important to be careful and patient when assembling the pieces, as any mistakes could result in a weak and unstable boat.

Once the frame is ready, it is time to lay the fiberglass, and apply the epoxy to seal the boat.

This is an important step, as it will make sure that the boat is waterproof and durable.

Finally, you can add the finishing touches, such as the hardware, paint, and rigging.

With the right amount of patience and attention to detail, you can have your own custom catamaran boat in no time.

Laying Fiberglass & Applying Epoxy

When laying the fiberglass and applying epoxy, it is important to take your time and be precise.

Fiberglass and epoxy are key components of a catamaran boat, as they provide the strength and waterproofing necessary to keep the boat afloat.

Start by laying the fiberglass over the frame of the boat.

Make sure to cut the fiberglass to size and overlap the edges for a strong seal.

Once the fiberglass is in place, mix the epoxy and begin to apply it.

It is important to apply the epoxy in a thin, even layer to ensure a proper seal.

Make sure to move the epoxy around to get it into all the nooks and crannies of the boat.

Allow the epoxy to cure and then you can begin to add the finishing touches.

Finishing Touches

Once the frame of the catamaran boat is built, it is time to add the finishing touches.

This includes adding the necessary hardware, painting, and rigging the boat.

Hardware: Before adding the hardware, it is important to ensure that the frame is stable and secure.

Add the appropriate hinges, screws, and nails to the frame.

Make sure that the screws and nails are the correct size and do not exceed the recommended load capacity of the frame.

Painting: Once the hardware is added, it is time to paint the boat.

Choose a paint that is suitable for the materials used in the construction.

Make sure that the paint is applied evenly and that the frame is completely dry before applying the next coat.

Rigging: The last step is to rig the boat.

This involves attaching the sails, running rigging, and standing rigging to the masts and booms.

Make sure that the rigging is properly tensioned and secured.

Once all of these steps are complete, your catamaran boat is ready to sail.

Hardware & Paint

The last step in building a catamaran boat is to add the hardware and paint.

This step is often the most rewarding, as it is the finishing touch.

Depending on the design of your boat, there are various types of hardware you may need.

Some of the most common items are cleats, winches, fasteners, and decking.

After selecting the required hardware, you will need to install them on the boat.

It is important to use the correct type of screws and bolts, and to secure them tightly.

Once the hardware is installed, it is time to apply the paint.

The type of paint and color you choose will depend on the design of your boat.

It is important to use a high-quality marine grade paint that is designed to handle the extreme environment of the ocean.

If you are up to the challenge, you can add some custom artwork or detail to your catamaran boat.

Adding the hardware and paint is the final step in building a catamaran boat.

With patience and attention to detail, you can create a beautiful and unique boat that will last for many years.

Be sure to take your time and enjoy the process of constructing your own boat.

Once you have finished the frame, fiberglass, and epoxy of your catamaran boat, you will need to move onto the rigging.

This is a crucial step in the construction process, as it will keep your boat safe and secure on the water.

When rigging a catamaran, there are a few key components that must be taken into account.

First, you will need to determine the type of rigging you will be using.

Typically, catamarans use a combination of standing and running rigging.

Standing rigging consists of cables and lines that stay in a fixed position to provide stability and strength to the boat, while running rigging consists of lines that are used to adjust the sail and mainsheet.

Additionally, you will need to choose the right type of rope and hardware for your rigging setup.

The rope should be strong and durable, and the hardware should be made of stainless steel and be corrosion-resistant.

Once you have chosen the type of rigging and hardware, you can start assembling the rigging lines.

This process involves carefully measuring and cutting the lines to the proper lengths, and then attaching them to the mast and boom.

Depending on the type of rigging setup, you may also need to attach the lines to the hulls and deck.

It is important to inspect the rigging lines and hardware regularly to ensure that everything is secure and in proper working order.

Rigging a catamaran boat can seem like a daunting task, but it is essential for the safety and comfort of your vessel.

With the right tools, materials, and attention to detail, you can successfully and safely rig your catamaran boat.

Final Thoughts

Building a catamaran boat is a rewarding experience that requires patience and attention to detail.

With the right plan, materials, and steps, you can build your own boat in no time.

Now that you know the basics of how to build a catamaran boat, why not grab your tools and get started on your very own project? With the right motivation and dedication, you can make your dream of owning a catamaran boat a reality.

James Frami

At the age of 15, he and four other friends from his neighborhood constructed their first boat. He has been sailing for almost 30 years and has a wealth of knowledge that he wants to share with others.

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Time For a Catamaran Adventure

Isn't Time For Yours?

Building Your Own Catamaran

Building your own catamaran is another option to getting into your own boat. In this page we will go over the advantages, considerations, and a detailed history and journal of our boat-building adventure with Light Wave . We hope this will give you a clear picture of what lies ahead if you go this route, including:

• Construction methods
• 9 essential design features
• Review of the four leading catamaran designers for home builders
• Construction times
• Budget: How much did it cost to build a basic cruising catamaran?
• Layout of our catamaran, LightWave , and lots of pictures
• Carllie’s article from September 2000 Multihulls Magazine: “The Boat Builder’s Wife “
• Equipment outfitting
• Radio and communication outfitting
• Dinghy selection and considerations
• Having a boat custom-built for you

Because of the huge dollars needed to buy a new or even a used catamaran, we would never have gotten a catamaran if we hadn’t built it ourselves.

Let’s start by saying that building any type of larger boat, especially a catamaran, can be one of the most intellectually and physically challenging things you will ever do.

It has been said that building a large boat is the closest a man can come to giving birth to a baby. In other words there is going to some discomfort and pain along the way; you will question yourself on whether this was such a good idea; it’s very difficult to reverse the decision; and though friends will support you, you will be on your own most of the time with your significant other if he/she is game.

Know your boat

You will intimately know every part of your boat. You will know where every wire, hose, bolt, bulkhead, rib, and support is because you installed them!

Pride of ownership

We have often thought what it would be like to just buy a boat from a manufacturer, and know that while owners who have spent a lot of cash (or future life to pay off the lien) their often possessive and competing-with-the Joneses could not begin to compare to our quiet glow of happiness and akinship we feel with Light Wave .

Our boat is like part of the family. So much time was spent on her that we have a major emotional investment. Every time we see our vessel – from a distance at anchor or approaching her in our marina, we say, “What a pretty boat! I can’t believe we built it!” Then that sense of accomplishment settles back in and we feel we have indeed earned the privilege of all of the beautiful experiences we have had sailing, cruising, exploring the beautiful BC Coast and much further a field (or should we say “an ocean”?).

You will be able to pay for the materials as you go and “donate” your time to the cause.

Get a newer design

Many of the production boats that are out there are designs of many years ago because the manufactures have to recoup their capital investment on the mold and production setup. When you build your own you have much newer designs to draw from.

Details on Our Boat Building Adventure

We had sailed our first boat Wave Dancer for five years and had many adventures on the British Columbia coast. In May 1996, I had just returned from a little one-week solo trip in the Gulf Islands of BC when I bought the book, The Cruising Multihull by Chris White (Future link to book review on our web site).

This is the book that got me going (Carllie was not yet convinced). I must have read it a half dozen times over the next 6 months, each time becoming more convinced that this was the way to go for our next boat. It was really still pre-internet web site days so I wrote to all the designers that were listed in the back of the book. Over the next several weeks packages of information started appearing in the mailbox (there is just something about getting packages in the mail – I guess it’s the anticipation). I would pour over these preliminary printed pages with pictures and accommodation layouts. Next, I put a few dollars down to buy the information packages and study plans from the top prospects.

I waited patiently for the study plans. It was like the night before Christmas when I was kid. Oooh the wait! Finally they came, and again I carefully scrutinized the next level of detail. Things were getting a little more serious. The top contenders were:

• Richard Woods
• Chris White
• James Wharram

Click here to read my comments and reviews on their catamaran designs as well as those of Jeff Schionning.

I remember initially drooling over the Atlantic 42 by Chris White, still one of my favorite designs. It seemed to be so seaworthy (by the way if I run into about $800,000 USD any time soon, I am going to buy an Atlantic 55). The most important piece of advice that came out of the material was from Richard Woods:

“Build the smallest boat you‘d be happy with it.”

Axiom #1: The hours to build a catamaran is in almost in direct proportion to its weight.

Which brings us to Axiom #2:

Axiom #2: It takes about 1 hour to create 1 pound of finished boat.

In our case we spent 3,500 hours ( click here for full details on the construction hours ) to build a 4,000 lb. boat (just a little less than 0.9 hours per pound). If a boat’s empty weight is 8,000 lbs., it will probably take about 6,000 hours to build.

When you think about it, you can only mix and handle so much material per hour. More boat weight, more material, more hours. Sure there are some economies of scale on a bigger boat, but usually the systems become more complex and these take longer to install.

This decision process took 8 months and I figured we’d launch in 6 months. It was now January of 1997. Little did we know it would be 26 months and 3,500 hours between the two of us until we launched on June 5, 1999. We ordered the full plans and we were off and running.

We were ready to build, but where would we start the process? First of all, we live in a tiny 480 sq. ft. apartment in Vancouver. Back-yard building wasn’t exactly an option so I found a small garage nearby that we rented for 5 months.

After about 4 months in the garage, I had made all the small parts and it was time to build the hulls. This meant that we had to go larger facilities. We found space at Shelter Island Marina and Boatyard in Richmond. This is the biggest boat yard in the Vancouver area with dozens of commercial and private projects, big and small, under way.

We were out of money by then, so we sold our first boat so we could buy resin and fiberglass. It was a traumatic time as we said goodbye to our beloved Wave Dancer . We were now committed. We than had all the foam for the hull cores, barrels of resin, and huge rolls of matting and roving needed for the fiberglass skins delivered to our “domed stadium”. We kicked ourselves many times that we didn’t take a picture of this raw material stacked in one corner of the empty shed, so we could later show “before” and “after” photos. It was time to build the hulls.

Over the next several months we proceed to join the hulls with the beams I had built in the garage, and then to install the cuddy cabin, cockpit, and decks. By the spring of 1998, it was staring to look like a catamaran. Through the spring and summer of 1998, we continued with the major structural components: mini-keels, hatches, stairs, and interior. Then we went on to the very laborious work of fairing the boat before painting. Don’t under estimate that job!

By October 1998 we were ready to prime the boat and start painting. I really thought this would go quickly. I forgot that I would have to do two more complete sandings to sand off and finish the two layers of primer application. In addition we had to fill countless pinholes – a laborious process somewhat like hiking up a mountain – each time you get to what you think is the top, you see another summit!

The boat seemed to get bigger and bigger. Believe me, there is a lot of surface area on a catamaran. I clearly remember that last sanding: I had reached the end of my physical and mental endurance – I was exhausted. I was ready to move on to the next phase – any phase but more sanding!

We now started spray-painting the hulls bright yellow. It was around this time we decided on our boat name of Light Wave . The painting took over a month: the hulls being the easy part, it was the topsides, the nonskid, and all the masking and prep that seemed to take forever. Happily, the worst of the dust was gone.

By March 1999 we were in the home stretch. The center bridge deck cabin was completed so we took a week off from our paid jobs and lived on the boat in the shed so we could work all day and not waste time commuting. March, April and May were frantic months as we finished all the final touches: engine installation, rudders, windows, deck fittings, electrical, plumbing, mast, and rigging. See our outfitting page (for more details on what we picked and why, and things we would do differently now.

Initially, our electronic systems were relatively basic but included GPS and autopilot see the following link for all our electronic outfitting choices and reasoning for more details.

It was May 22, 1999 and we decided that Saturday, June 5th would be “Launch Day” so we could send invitations to all of our friends. On the Friday night before Launch Day, we still had a number of final things to do, many of them outside. Unfortunately it was pouring rain. We were tired and very wet but the boat had to go into the water next day so we persevered on till everything was ready.

The moment of truth came as Light Wave was lowered into the water. While still in the slings of the Travelift, I jumped aboard to check for leaks. Of course there weren’t any! More food and laughs and tours of the boat for all attending. It was a great day.

Emotionally drained that night, we slept in Light Wave in the water for the first time. It was another week before we actually went out for our first trip as we had to sell the shed, setup sails, and install some final deck hardware.

To sum it up, building a catamaran was a great experience. We learned a lot. Carllie and I grew closer together through it all. We had a great time doing it. We had a beautiful catamaran to show for it. Now it was time for a catamaran adventure !

snapshots of building a sailboat

Building a sailing catamaran.

A collection of sailing catamaran building logs, from choosing sailboat plans to yacht launch...join us on our journey

This 'glass-over-ply' sailboat is proof that a DIY'er can successfully build an ocean-going multihull cost effectivly.

Having reliable Boatbuilding Resource Books , WILL HELP fast track your decisions prior to, during and post building.

We also wanted a light sailing catamaran that we could beach with ease. This now allows us to save money on one of the biggest maintenance DIY chores, sailboat antifouling without having the costly expense of slipway fees.

Where do I start?

Plywood and Epoxy Catamaran Why both? 

Plywood construction is the cheapest building method available and very forgiving while one hones their skills.

Finishing with a solid fiberglass outer is also a task made easier, given the amount of glassing and gluing needed during such a project. Doesn't make sense? Read more...

Talk to the sailboat designers , get to know their design types. Get on Forums and ask the 'dumb' questions. Go to marinas (not boat shows) and look for home-build yachts.

how to build a boat

"It takes a strong desire and a will to achieve. Building a large catamaran is certainly achievable". "If you want a yacht with all 'bells and whistles', keep working because it costs money...a lot of money". J Coomer

many sailboat plans to choose from!

Is it cheaper to build or buy? There are many yacht plans to choose from, but dont kid yourself. Many have tried to do it on the cheap and their result shows. If there was a cheaper way, the sailboat designers would tell you. Afterall, they would use that reason to sell there plans!

catamaran sailing

DIY boat projects on Pure Majek from new navigation equipment, anchoring systems, rewiring yacht electronics diagrams, AIS and much more.  Its been ten great years since launch and we look at things that have worked and those we would change. Join us and be inspired.

goal setting, planning and building

Setting achievable goals and how to stick to them. From the planning process, what and why we did many things, importantly, things we would do differently. The following pages draw on these experiences described in far more detail in our book ' A Sailing Catamaran Building Adventure '

‘Green power’ is climbing up the priority ladder to such an extent nowadays that some predictions of fossil fuel costs (scorned at a few years ago), are coming home to roost.

two-pack painting

There are a few tricks here to with respiration, thinning of the topcoat, temperature and coat thickness. All achievable by setting goals and being disciplined .

Building catamaran Pure Majek videos

Just want videos?  Click our Youtube Channel . Over 500,000 views and counting. NO TALK videos . Thank you for your support.

Catamaran Hulls

Click photo

Catamaran Fitout

Catamaran Internal Painting

Bridgedeck & Turret

External Painting

Final Fitout

Antifoul & Decktred

Fitout, ready for launch

building: puremajek.com

sailing: diycatamaran.com

© Copyright 2009-2024 www.diycatamaran.com - All Rights Reserved

No video? EMPTY CACHE from your device, then UNMUTE .

No video? EMPTY CACHE   from your device, then  UNMUTE .

Starting out

Internal Painting

Bridgedeck and Turret

No video?  EMPTY CACHE from your device, then UNMUTE .

DIY Styrofoam Catamaran

Introduction: DIY Styrofoam Catamaran

This is a Styrofoam catamaran i built. I had been wanting to build this for a while, then in the last few days of summer i decided to build it. This only took 2 full days to build and one day to test. The catamaran costed me around 200 dollars (sail not included) and this is comparable to a store bought catamaran which would cost 2000 dollars

In this instructable i have included a few schematics (located on the last page) , a materials list, and various pictures and descriptions for all steps.

If you plan to build this project i suggest you check out the video and if you like this project be sure to check out my channel or my website for more projects like this.

Step 1: Materials

The materials i needed for this project were:

2"x4"x8' pieces of wood - 2

2"x3"x8' pieces of wood - 1

2"x2"x8'pieces of wood - 6

1”x2’x8’ Styrofoam sheet - 5

1.5”x14”x4’ Styrofoam sheet - 5

½’’x2’x4’ piece of plywood - 2

½’’x4’x6’ piece of plywood - 1

Sail and mast - 1

Epoxy (dollar store epoxy is cheapest and works well) - 7

Step 2: Assembling a Pontoon

The catamaran will be composed of 2 pontoons. These pontoons will have a frame filled with the white, less durable Styrofoam in the center; then we will later add the pink Styrofoam to the outside.

To start off i lay out two 2x2 pieces of wood with the white Styrofoam pieces in the center. This will be the inside of the pontoon. Next i add a front triangle onto the pontoon. As you can see in the third picture i added 2 struts near either end of the pontoon. Once that is finished i fill the pontoon with white Styrofoam and cut it to fit in the gaps.

Step 3: Finishing the Pontoon

to finish off the pontoons we must first cut 4 pieces of Styrofoam to size (2 for each pontoon). To cut them all at once i clam them together and use a reciprocating saw to cut the height from 2 feet to 17 inches (the height of the pontoon).

After that i use 1 - 1.5 tubes of epoxy as adhesive. I spread the epoxy on the wooden frame and then lay the Styrofoam down onto the wooden frame and add weight to it so the Styrofoam stays tight to the frame as the epoxy hardens. After that i use the saw to taper the bottom edge. I also add Styrofoam to the front triangle and taper that as well. Once complete you should go ahead and do that for both pontoons.

Note: The strut layout in the second pic is different then the layout of the of the struts in the previous page. The layout in the previous page showed the correct positioning of the struts.

Step 4: Completing the Pontoons

Now you can see both pontoons side by side. To complete them i add a wooden triangle positioned at the top, and lined up with each strut, this will be used for mounting the frame. To add some more buoyancy i also cut a full 2' x 8' piece of Styrofoam in half lengthwise (giving us two 1' x 8' pieces). I use epoxy to mount those onto the inside of the pontoons.

Now both pontoons combined give a buoyancy of 460 lbs when fully submerged. This seems like a lot but when you consider you wouldn't want more then 60 percent of the pontoon submerged (then you would be uncomfortably close to the water) and you might also have you weight towards one side of the pontoon then it seems this 460 lbs is just enough for one person to float comfortably. (i fit 2 full size people on but it sits very low). If you wish to be able to make this a 2 person boat you can add more Styrofoam sheets to the outside. Each 1"x 2' x 8' sheet once cut to a height of 17" provides 62 lbs of buoyancy when fully submerged.

These calculations are fairly simple to do on your own. First calculate the volume of the object (length in meters x width in meters x height in meters), this will give you volume in meters cubed. Then multiply the value you get by the density of water (1000 kg/m cubed) this will give you how many KG the object can float when fully submerged.

Step 5: Making the Frame

To make the frame i cut my 2x4 s to 4.75 feet long and attached them to the pontoons using screws. I chose that width because it was just small enough that i would be able to fit the frame (when separated from pontoons) in the back of my van. Next i add the 2x3 piece down the middle of the boat. This is both for structure and to mount other parts off of.

Step 6: Adding the Keel

Now i cut out the keel out of a piece of plywood. Using the plywood, i also glue a slot so that the keel can be slid in and will be able to slide up and down within the slot.

The keel is an essential part of the sailboat and helps to turn the force provided by the wind into thrust in the forward direction. This is also the pivot point when you turn your boat

Step 7: Adding the Rudder

The rudder will need to rotate so i decide to mount it off of a hinge. I add a hinge to the back of the boat and then cut the rudder out of the piece of plywood. The rudder should be fastened in place with 2 bolts and the bolts should have a washer in between the nut and the wood of the rudder. The bottom bolt will have to be taken while the boat is out of the water so that the rudder can pivot upwards when it is on dry land.

To finish off i add a handle made of plywood. The handle is to only have one bolt through it so that it can pivot up and down.

Step 8: Finishing Touches

To finish up i cut a piece of plywood to size and fit it on top of the catamaran to use as a seat.

After that we need to make somewhere to mount the mast of the sail. To do this i obtain a small piece of pvc pipe and heat the bottom of it so i can squeeze it down and make it thin. Once that is done i simply mount a few screws in it to attach it to the frame of the boat.

Step 9: Setting Up the Sail

Now i use a mast and sail that i had laying around and slide it into the pvc pipe. I secure the mast with metal cables that attach to various points on the boat. Once the mast is in place i rig up the main sail and the jib and it is now ready to sail

Step 10: Testing Out the Boat

Now that the boat is complete you can go ahead and take it out on the water and test it out. Be sure to wear a lifejacket and bring a paddle just in case you have a hard time getting it in using the wind.

To see the test you can also check out the video

Step 11: Schematics

Here are a few schematics of the boat, they are not to scale. Beside the schematic picture i also attached a real picture of the boat

In order we have a top view of the boat, a front view, a side view, and a picture of the rudder and keel. All measurements of the schematics are done in meters.

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