Formula 40 singlehanded trimaran build log

The new owner of Gecko Kurts F40 trimaran is carrying out a refit and some mods and detailing it's progress on FB. It looks great so far and it will certainly be useful to have a bit more space around the midships area for a bunk:

https://www.facebook.com/pages/Gecko/328374460702512

 

Any news !

Hey..

Have you any news of your tri build ?

 

Hi Splinter,
I haven't progressed much on this project lately still gathering materials and fittings for the build.

 

I really like the look of the 40, I'm thinking about doing a simular build. In the past I have built a wharram cat and built my current boat which is a cruising version of a mini transat. Do I understand correctly that with your plans the hulls have been updated with a more modern reverse bow ?

Is it possible to have a flick up rudder arrangement so you can dry out ?

I have trouble insuring my mini the insurance companies are so scared of them, even though I'm sensible and don't race, will you be able to get insurance for this design ?

Have you done some rough estimates for costs for the entire build !

Sorry for all questions, I'm just really interested in this design and so rare to find anyone building it.

Currently I'm sailing out to Newzealand from the UK in my mini !!

 

At my current estimate if you do the work yourself it's about 30 -35k to build the platform in CM with a lot of variation depending on what material choices you make. Kurt is really good on this front and will give you a lot of information as to material substitutions and what cost/benefits they will bring. There is a kickup rudder drawn as part of the plans but a hinging transom like the one on Loick Peyron's trimaran "Happy" would work well too.

The rig could easily be around the 50k mark and sails are also very expensive I've been annoying various spar companies over the last few years to see if they have any good s/h masts available. If you buy a bare section and fit your own spreaders and mast fittings there is some money to save. Your experience in mini sailing would give you a good idea as to how to work with the minimal payload this design offers. With a bit of careful thinking you can meet Cat1 safety for offshore work.

Space is pretty minimal onboard on the rebuilt Gecko they have inserted some basic wing berths and raised the coachroof slightly to make it more liveable would be a good idea if you were going to try and cruise this design. Perhaps Kurt's 40' trimaran cruiser might be worth a look if you want more space and payload.

Keeping everything light has some real advantages the low displacement keeps the righting moment under control which means your gear and rig doesn't have to be too heavy. The float hulls have been redrawn with a subtle reverse bow. Insurance isn't easy but in Australia Youi is insuring racing trimarans and apparently some other insurers will look at trimarans on a case by case basis.

 

Thanks for your replies, there really helpful.

Yes I agree about the more cruising design but I really like the idea of the minimal drag hull shape, I think this design will be very smooth to sail.

I have lived on my mini now for over two years and sailed 4000 offshore miles and have gotten used to the minimalist way of life. As long as I tranfer my sailing/safty gear from the mini I should be ok. I'm not sure of the weight of all my gear but minis are small so can't be too much.

The rig does look like the crazy price but so would have to get a bare pole and finish the rig myself, maybe with pbo style soft rigging that I can splice myself to reduce labour.

Also the main is huge..so expensive as will but as the boat is so over canvased and light I'm sure I could stand a few seasons with just a main and headsail to keep costs low.

I was looking at what they did to gecko and I like the idea, I was thinking about something simular but more in keeping with the lines on the boat so it doesn't look like a add on. But might then need to think about a different construction like cedar maybe so I could get a more organic shape.

If the rig is going to be really expensive, I wonder about building a carbon one? Not sure I can lay up 60 feet of carbon and keep my cool though before the vac pump is switched on!

 

Since you mentioned cedar / strip have you seen Kurts updated offshore 40' racing tri?

http://www.multihulldesigns.com/designs_other/40racingtri.htm

It has a nicely flowing cabin enlargement over the F40 design.

 

A solution might be to build a carbon main hull obviously it adds cost to the build but your budget may be able to cope (mine isn't that flexible). The good thing with this design is that it's demountable so mixing materials is pretty easy. The obvious place to save weight is the main hull it has the maximum surface area so some savings can be made there. Adding nice curves makes the boat more attractive but comes at the cost of more surface area and weight. A good option which I've looked at and which doesn't add too much weight is to have a plexiglass canopy over the widest point of the main hull it opens up the boat a bit and gives more headroom where you need it round the centre of the hull without jacking your freeboard too much.

The flared hull concept racing trimaran was I believe intended to be built in carbon which is the way Phil started building his trimaran even though it is listed vaguely as composite on the website. It's pretty hard to keep weight under control with more surface area without using more expensive composites or increasing displacement. The rub is the more composites you use the higher the cost so you get back onto that treadmill if you want to keep the fine and easily driven shapes that a lightweight design gives you.

 

I don't mean to hijack your thread...

Yes I'm coming around to what your saying. My budget is also minimal and i can see how easy it would be to get carried away.

So far I have come to the conclusion to keep things the same as it was designed. I would rather have less interior space but keep the light wind performance.

As I undrstand Gecko was build with balsa core ? Was this vac bagged to the ply while still on the mold ?

I have not yet been on a tri this large before, I can see the design will be great in light wind but how do you think she would handle offshore in strong winds. ?

With the slender hulls I would think she would be very smooth.. Just out of curiosity, Would a design of this age be able to fly its centre hull ?

Gecko looks to be in very good condition, Are there any more KH F40's out there like Gecko ?

 

Gecko was the class leader and as far as I know the only one built it was constructed on a female cylinder mold while Kurt was still developing his ideas. The balsa core is vac bagged inside the cylinder molded ply skin for panel stiffness. You could also use a foam core or stringers. On my build I was thinking of using stringers in the floats as they work out a bit cheaper overall than core but on the main hull core is the better option imo. Space is limited so making the most of every bit of it becomes more important.

Kurt expressed no concerns about the boat offshore and he has done quite a few designs so far for ocean usage and F40's have done Transats etc in a range of conditions. You don't have much weight in this boat so it will move around a fair bit offshore with a quick motion which can be tiring. In strong winds you can reef right down and run with it if you have sea room. Some people recommend sailing to windward as a good option. You can also use a parachute anchor if you want to heave to and it's good to make sure you have adequate cleats to take the loadings which are imposed.

One of the reasons I went with this design is the demountable option it's feasible to pull the boat down and ship by 40' container to a racing location and do qualifications in the area which saves a fair bit of wear and tear on your gear and sails.

 

maybe instead of roof blister you can do a bit of what kurt did with his simple 30. looks clean and adds a bit of headroom for minimal additional work. he basically swooped roof with sides to match. No added funny side trim or drop decks to graft in, just simple raised sides and roof to match.


Barry

 

You could raise the freeboard a bit in that way Barry I'm not keen on the aesthetics though. From a racing perspective I don't really mind the flush deck. I see that you would enter the cabin and sit down with the nav console mounted on the daggerboard case with the galley opposite and have a bunk in the same area so tight accommodation for one. Just aiming for adequate for racing and hotbunking if need be when shorthanding. I'm keen on building some kind of upright chair for sleeping in too like the custom one that Charlie Capelle built for acapella.

 

yeah i like the flush deck as well! I thought his slight bump looked and served better than just raising free board all over. Thats just gonna start adding more boat and side sheer for no reason. In the pics of a built one it just looked nice and clean and flush, just slightly popped up. Even the decking went unbroken or hindered from bow right up curve to cockpit.


Barry

 

A bit of progress lately on this build with the help of Mark from Australian Boat Brokers at Lake Macquarie a suitable mast and sails was found and purchased for a reasonable price. The 43' Malcolm Tennant Bladerunner design cat "Matchless" broke it's mooring and sadly was destroyed on rocks. The mast and sails were able to be salvaged relatively undamaged from the wreck and will become the rig for my yet to be constructed F40 platform.

The Matchless rig is slightly lighter than the one specified for the design but with an additional cap shroud on the rotating mast we should be able to get away with it.

 

Corley, you are a real "bad man"

Keeping totally silent about your self building project, while I put the question on the table with a new thread on the table: "What about the future of Formula 40 Trimarans?"

haha... good luck for your project. What is the given "deadline" till we see the christening ???