This website documents my progress in building a Farrier F-85SR trimaran.


dutch flag

Why build when you can buy?


I wanted to build my own boat, even though there are several arguments for not building, like on this website.  What counts are the reasons for building your boat. Do you just want to save money, or are you interested in the building process. 

I have a great job. Although I’m away from home for several days in a row, I’m also at home when others are at work and my children off to school. There is one disadvantage to my job however: When I drive home there’s nothing to show, only memories.

When I started flying model airplanes back in 1999, I discovered that I liked building them even more than the flying. It’s great to see the result of your work in a flyable gadget. Soon I started to design and build my own airplanes and after some time the desire arose to build my own boat, as I also like sailing very much. I own a Nacra 500


What kind of boat?


The wish to build led to a search on the internet. There’s a lot of information out there. To sort it out, it is important to define the requirements for your boat. For me that means a fast day sailer that I can sail solo and which I later can use for cruises of a few weeks. Also I want to be able to dry out. 

It can be tempting to look at boats that are bigger than you actually need. A bigger boat is more seakindly, has more space and is often faster. However, a boat that is 3 ft longer also is 1 ft wider, is heavier, needs bigger sails, bigger engine, winches etc, etc.. And is a lot more work. Maybe not so much in building, but fairing and finishing will take a lot more work. Also a bigger boat is more expensive. Therefore it is important to look for the smallest boat that can fulfill your wishes. 

At first I mainly looked at monohulls and arrived at the website of Dudley Dix. He developed a great building method for plywood-epoxy boats. 

Further search led me to schionning designs which had just released a new design: The  Radical Bay 1060 . The studyplan left a few questions about the interior, which I wanted to change anyway, so I decided to build a 1/6 scale model, based on the studyplans, of the starboard hull to check things out and develop a ‘feel’ for the size of the interior. 


After this I was almost ready to order the drawings. A visit to a Farrier builder and a testsail on an RB8000. (thanks Ian!) made me doubt. I liked the design of the RB1060 and I think it will be a great sailer. The open bridge deck and the sideward facing cabin entries lack protection against the unstable Dutch weather however. 

I researched the internet again, visited an F-32 and an F-82 and crewed on an F-31 in a race. At the same time a new design was brought out, the F-85SR. It's a bit smaller and an exact fit to the most important points on my wishlist! The F-85SR is a development from the F-82, with changed hull shapes, a bit more sail area and a more efficient dagger board and rudder. A smaller cabin is standard. I made a longer cabin like on the F-82. My F-85SR has sailnr. 2

Farrier Marine stopped all plan sales. Now and then unused boatplans come up for sale. This is generally published on the Farrier/Corsair Trimaran forum or on Sailing Anarchy. Till some time ago it was possible to re-register the plans, but after Deadalus bought the company the status of the drawings is uncertain. Support of builders disappeared with the death of Ian Farrier, but there is a lot of knowledge on the Farrier/Corsair Trimaran forum. However, Farrier Marine does not supply parts anymore according to some forum members.

Length: 8.50 m
Beam: 6.00 m, 2.50 m when folded
Mast length: 12.30 m
draft: 0.30 - 1.85 m
Sail area 42 mē
Weight +/- 1100 kg

New to the F-85SR is the use of the curved lifting foils. These were originally designed for the F-32SR, but are also usable on other designs. The major advantage is that they work as a hydrofoil for the lee hull. They are not supposed to make the boat fly fully ( foiling ) but to reduce the amount that the lee float depresses into the water ( foil assist ).

f-85sr curved foilfarrier folding source:

As the floats can be folded, the boat doesn't need a lot of room and a normal 10 meter berth can be used. Also it can legally be transported on a trailer behind a normal car. This is a video which shows how the floats are folded.

Interior design is free and cabin length can be varied, as long as the main bulkheads are kept in tact. There are plenty possibilities. The final choice was not due until the later building stages. I finalized the design before I started building the main hull so that the parts could be build in when access is still easy. Basically I limited the settee length to the short cabin design while placing the cabin bulkhead roughly in the F-82 position, creating extra room.

f-85 interior view


Looking back


Building a boat is a great experience. In hindsight it took me quite a bit more time than I expected. In the planning stage I thought it would take me about 5-7 years, based on the 2500 building hours that it would take according to the designer. It turned out to take more than 4000. Also, working alone is not very efficient, I found out. Designers are generally quite optimistic in their build time allocation. The extra time is not a big problem, as I had not set myself a launch date goal and I enjoyed the building process.

Working with vacuum is also time consuming, but does give a stronger laminate with a more constant quality. This project is on the edge, size wise, unless you can employ extra people for the bigger parts. Those bigger parts sometimes had me working 8 hours in a row. Vacuum infusion will be a bit more relaxed as your not chasing vacuum leaks with the clock ticking.

Often I worked on several projects at the same time, so I would not be idle if I ran into problems on one project. I also changed the build order. The ( excellent ) build book continues work on the main hull when the floats are ready. I left this to the end. When the main hull is ready, it looks like the boat is almost finished, while there still is a lot to do. This can be hard on your motivation. That is why I first build all parts, like the rudder, daggerboard, beams etc, before I started work on the main hull. That worked out well.When you need the daggerboard case, while working on the main hull, you just pick it from storage. this way you finish intermediate stages and have a new goal to work to each time.