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Wharram World

Distant photo of Wharram Tiki 46 on the water with all sails up

Dream, Build, Sail

Build your own catamaran renowned for its seaworthiness, stability and safe simplicity. All Wharram plans are drawn for the first-time builder.

Aerial view of 5 colourful Wharram catamarans at the beach

A Global Family Of Sailors

The Wharram World circles the globe. Wharram catamarans have been built and are sailing in all the World's oceans.

James and Hanneke in their design studio with Amatasi model

Trusted, Proven Designs

We believe the ancient Polynesians knew a thing or two about building boats to last. Wharram catamarans are proven survivors.

Wharram Mana 24 with white and teal hulls, with deck tent on board

Mana 24: Boat In A Box

Assemble her yourself from pre-CNC-cut plywood parts. Keep it at home, trail it and sail it anywhere.

Seaworthy. Simple. Affordable.

Building your own boat with Wharram Designs is the easiest and most cost effective way to fulfil your sailing dreams. Wharram Self-build boat plans start from only £120.

Wharram designs are based on years of practical, hands-on experience of building and ocean sailing catamarans. They are renowned for their seaworthiness, stability and safe simplicity. Designs from 14’ - 63’ are available for self-building in ply/epoxy with very detailed, easy to follow Plans often described as 'a course in boatbuilding'.

Study our Self Build Boats to familiarise yourself with our range of designs and their unique qualities. Download and read the Wharram Design Book which reviews each design in detail and offers a detailed introduction to the world of self-build catamarans. Order and download Study Plans and immerse yourself into the boat builder's mindset; evaluate the costs; the amount of time required to build your boat; where you will build it and where you will eventually launch it.

Once you have decided on the boat that is right for you, order your Boat Building Plans . All Wharram building plans are drawn for the first time builder, so anyone with a modicum of practical ability can build one of our designs. Our Building Plans present quality instruction, guidance and advice for both novice and professional alike. They are all based on decades of actual building experience and thousands of ocean miles sailed.

Go on adventures and live the life of your dreams. Spend your weekends coastal trekking and camping, or live aboard and spend your days sailing around the world. Become a member of the global family of Wharram builders and sailors. Wharram catamarans have been built and are sailing in all the World's oceans and can be found in far away ports and anchorages.

The quality of the Wharram self-build catamarans is reflected in their popularity, excellence of craftmanship and sound sailing qualities. More than 50 years on - with over 10,000 sets of plans sold and thousands turned into proud vessels - Wharram 'Cats' can be seen in harbours across the world, maintaining the highest reputation for surviving wind and wave.

Find Out More

Self-Build Boats

Index of Wharram self-build catamarans. Familiarise yourself with our range of designs and their unique qualities.

Choosing A Boat

To help you select a design, read our practical advice about basic requirements, building times, building methods, and costs.

James and Hanneke in design studio with Amatasi model

Several articles giving an in-depth look at our core design principles and how they are reflected as seaworthy, stable vessels sailing the oceans.

James Wharram: Lifetime Achievement Award

A special award was presented to James Wharram for a 'Lifetime Achievement' as Pioneer catamaran builder - sailor and multihull designer.

James Wharram - British pioneer of the modern catamaran

About James Wharram

In the mid 50's, based on his research into ancient Polynesian boat design, James Wharram built the first off-shore Catamaran in Britain and sailed it out into the Atlantic. While the world's yachting community still did not accept such a design as a worthy sea-going vessel, James was landing his 23'6" 'Double Canoe' called TANGAROA in Trinidad in the West Indies.

There he built a second 40' Polynesian style Catamaran, RONGO, and in 1959 sailed it up to New York and back to the UK accompanied by two German women - being the first to sail a catamaran West-to-East across the North Atlantic. These amazing Trans-Atlantic crossings and the follow up book ' Two Girls, Two Catamarans ' have etched the name 'James Wharram' into the annals of yachting history.

Since then, James Wharram has been designing, building and sailing offshore catamarans longer than any other multihull designer. James was a 'hands-on' designer having, over his lifetime, built personally many of the prototype designs. These prototypes were built in the open, in barns, workshops and all the range of building sites available to self-builders, in a variety of climate types from northern European to the Tropics. James was often referred to as a 'Living Legend' or as written in 'Yachting Monthly' in January 2006: "James Wharram is considered by many to be the father of modern multihull cruising."

James’ last achievement was his autobiography published in 2020 as ' People of the Sea ', which he wrote in conjunction with his design/life partner Hanneke Boon. James died in December 2021 at the age of 93. The design business is carried on by his co-designer Hanneke Boon .

Hui Wharram Cornwall Gathering 2024

We are having another Annual Hui! This Hui will mark 70 years since James designed his first Catamaran 'Tangaroa' and we are excited that we will be mooring at Devoran Quay just a 5 minute walk from the Wharram Headquarters based in Cornwall. It would be lovely to celebrate his achievement with all of you.

Read more about Hui Wharram Cornwall Gathering 2024

Pacific Islander History Month

People wearing sarongs walking around a beached double canoe

This month of May in America is 'Pacific Islander History Month' and we at James Wharram Designs would like to join in and celebrate alongside them! As you may know, double canoes/catamarans are of ancient Polynesian origin. The modern day catamaran is a direct descendent of these original ocean-going vessels.

Read more about Pacific Islander History Month

James Wharram's Last Ride

On 23 July, a motley fleet of self-built catamarans gathered off Cornwall to give James and Ruth Wharram their final escort. It was a fitting farewell to a legend. The ashes of James and Ruth Wharram were consigned to the sea to be carried by the ebb current out to the open ocean.

Read more about James Wharram's Last Ride

James' Eulogy

Hi everyone. I'm Matt. And apart from being truly honoured to be here to help send James on his way to his next adventure, I am here above all as a representative, really, for the many many people worldwide who's lives have been changed, for the better, as a result of James' life work.

Read more about James' Eulogy

A Living Legend Lives No More

We are very sad to announce that on the 14th December James Wharram left this earthly world, joining Ruth, Jutta and his many close friends that departed before him. At 93 years old his spirit has set out on the voyage to sail the oceans of heaven.

Read more about A Living Legend Lives No More

People Of The Sea - Compact Edition

People Of The Sea - James Wharram with Hanneke Boon

The new second edition of the autobiography of James Wharram and Hanneke Boon is now available! This more compact edition at the lower cost of £16 contains all the text and illustrations of the special first edition. An easier size to fit the bookshelf on your boat. A must for all Wharram enthusiasts and other sailors.

Read more about People Of The Sea - Compact Edition

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!!

MIKE WALLER

Yacht design, multihull boat plans by mike waller yacht designer.

TC670 TRAILER CAT This is an all plywood, trailerable, of the beach sailing cat designed for sheltered and semi-sheltered waters. The cabin has a double berth, a galley, small table area and W.C.

TC750 CATAMARAN This all plywood cat is a larger and more able development of the 670, and being wider, is capable of more extensive adventuring.

W880 CATAMARAN This true ocean going little cat sleeps 4 and is built in strip plank cedar and glass composite, and plywood. Sleeps 4, and has a seperate WC / shower area.

W1100 CATAMARAN This Ocean cruising vessel is in all plywood, and is capable of extensive ocean voyaging. Sleeps 5 in three seperate cabins, with seperate W.C / shower area.

W1160 CATAMARAN This ocean crusing family cat is built from strip plank cedar and glass composite. She sleeps 5 in 3 cabins and has a seperate WC / shower area.

W1200 CATAMARAN This ocean cruising family cat is a plywood version of the 1160, with rounded, strip planked hull bottoms and the rest of the boat in plywood. The transom is slightly extended to provide a wider boarding step.

W1350 CATAMARAN This is a family cruiser in cedar/foam/glass composite, intended for world cruising for a couple or small family

W1480 CATAMARAN This is a true, proven, live aboard world cruiser for a family of up to 6 in four cabins. The vessel is strongly constructed in strip plank cedar and glass composite, and plywood. She will take you anywhere.

CS25 CATAMARAN This little demountable cat has two seperate hulls, each with two berths. She is all plywood.

CS35 CATAMARAN This cat has two seperate hulls with V shaped truncated sections, each has a double berth. She is all plywood and has a center cockpit which can be built in to form a shelter cuddy.

CC31 CATAMARAN This full bridge deck cat is in multi-chine plywood, and has two huge double berths, a dinette and seperate WC / shower area

CC40 CATAMARAN This ocean voyaging cat is in multi-chine plywood, and has two seperate hulls, a center cockpit with cuddy, and unbelievable accomodation for a vessel of this type and size

Construction plans only

The plans can be purchased separately and the materials can be sourced by the client at their own pace. A list of the required and recommended materials is provided.

Cad-drawn colour construction plans are supplied in an A3 sized booklet of high detail specifically suited to amateur building.

Study Plans

Study Plans are available for this design, please send a request via our Contact page.

How to Order your Spirited 480?

Purchase Order Please complete the online contact form. Online Form

Order Confirmation On receipt of your order form we will provide you with an order confirmation with the costs and deposit requirements.

Payment Generally a deposit is made at order and a final payment is made prior to dispatch. Payment for the larger design range is generally made via direct deposit and these bank details are provided on your order confirmation. Payments are made in Australian dollars.

Delivery Estimated delivery times is provided on the Order confirmation. We will contact you with a delivery date and delivery options once the kit has been ordered.

Contruction Plans Printed to order with customised cover sheets and any other design requirements to meets the clients requests.

Kits Pre-cut to order as standard or to meet any specific customised requirements.

Components Built to order as standard or to meet any specific customised requirements.