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Foiling Trailer sailer

Fiddling away .to actuate the flap on the main foil I needed to make 2 bronze rod ends and tap them for the 3/16 ss rod which will be the pushrod . Quiet afternoon on the unimat lathe . I finished prepping the main foil for shear webs and reinforcement around the ss 3/4 inch T ees which I then glue in place along with the rod end and ss 1/4 rod to move the flap . I will separate off the vertical and vacuum the 2 halves of the foil together then make a structural fillet .




Interesting times and slow boatbuilding . Cold weather minus 18 c here and -24 C at the hill but 30 to 40 cm of powder in places so worth it. The 22 nd was my last day of work with a retirement party after .somewhere in this week I contracted Covid and became symptomatic on Christmas Day and duly gave it to my wife 5 days later .no skiing then a rainstorm to 2400 m so good time to return to the garage as quarantine After 2 days in bed.
I glued and vacuumed the main foils together then sliced the flap off with my table saw. I am reaming out a space in the forward section for the top edge of the flap to slide into with the top skin extending over the upper part of the flap. I have laminated foam and glass cloth on the forward edge of the flap . This will be radiused and glassed for minimal clearance. 3mm inside Carbon tube wrapped in biaxial carbon is making the preformed hinge along with a Kevlar glass flexible joint .
I just brazed up the 10mm ss rod T S for the rudder foils .A breeze with my new welding helmet .


A little carbon glass laminating of the socket on the main T foil horizontal and flap . I created a hollow in the forward main horizontal foil and glued core cell foam onto the flap Which I then shaped in a reverse P shape prior to laminating . Very heavy laminate. 100 gm biaxial carbon and 25 gm glass cloth !!!! At least it drapes well . Next part is fiddling with the carbon hinges to get the most minimal gap then On to the fillet and bulb .
meanwhile I glued the ss T ees into the rudder foils and then glued the 2 halves together .






South Australia
Wow! In defence of my unusual cruising oriented power sailer which can plane under engine (very rarely used ability) I made a statement to a detractor that it will be a long time before they make foiling trailer sailers so purchased a UFO catamaran for my foiling sailing speed kicks.
Looks like you are trying damn hard to prove me wrong! Congratulations.
I have a bitza boat. Bit trailable cruising oriented sailboat, bit cruising accommodation oriented powerboat.
With lightness as an absolute key for your project I am not expecting your magnificent looking yacht will be carrying enough for weeks of cruising though.
Cross breading a mule with a cheetah is going to be interesting. :)

Thanks for your interest . I guess I am putting my money where my mouth is ! With hindsight I could have built her quite a bit lighter having seen Julian B 89 er scantlings mine look massive but light compared to Dave Gerr Hereshoff or Niven‘s rule s or ABS and similar to Dudley Dix .Hopefully it will tolerate rough roads on the trailer as well as crashes off the foils.
cruising gear will be limited but hopefully the red wine won’t get too shook up ! No planing under motor.
I am hopeful that the square cube law in reverse will allow some degree of foiling. If Ian ward’s laser can fly my power to weight and stability is similar courtesy of vampire project like foils . I will post some more photos soon
Glued together rudder box with slider for the top rudder location. lots of fore and aft movement 6.5 cm so a couple of degrees down to nearly 5 degrees up .
tiller are foam 20mm sandwiched between to 4 mm x45 fir with 6 and 9 mm plywood side plates then wrapped in 2x100 gm carbon biaxial with 3 layers of 400 gm uni 165, 100, 65 cm long .unfortunately all a wet one hit layup with wrinkles so more bogging!!! Very difficult getting peelply off.
However that should be the last major vacuum layup .
fillets , spreaders and flap hinges next .
Norths are moving with the sail and we are waiting on sail number and mast track hardware .
i have ordered MMA 422 to glue the windows and mast track on from glueguys .



I live these days just above the US border 1/2 way across BC .
I'm a trailer sailor down in Surrey. I get up to Nelson once in a long while and would love to see your project some time. In the meantime, please keep posting updates!

If you come down to the coast when she's done we could go for a sail together. I won't be able to keep up, though, as my boat is strictly a cruiser (TES 246 Versus).
Hi Chris,
Recently found your impressing foiler build and I am looking forward to the result.
What will you use to adjust rudder foil AoA?
I am building an electrical MCU controlled system with angle sensors to experiment with. The idea is to keep the boat horizontal automatically. As I am lazy, I bought a Waszp rudder box with its mechanical components for manual override through the tiller extension. Image shows mockup.

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Hi Lars.
your rudder control looks interesting . Mine is very simple 4 :1 purchase to pull the end of the rudder back in the slider . This will be lead forward to the traveller fixed block where I have a spare sheave thru a cam cleat then across and back to the other rudder box . This way I can adjust the leeward rudder from windward like an A class with the possibility of making them self tacking . Not as sophisticated as electric servo ram control !
Obviously this is like a moth and will set global relativity of rudder to main foil. Hopefully my wand and hydrobalanced flap will achieve adequate height authority. Time and experiments will tell.
I have been working on the flap hinges and am reprofiling the leading edge to better mate with the hollow/ con cavity in the main foil plane .
I have also had my friend Danny around to help with the trailer . We cut a 10 inch diameter stainless tube in half to make a trough 2.4 meters long for the keel bulb to slide into when on the trailer. He is an excellent welder and fabricator who may help me with the overcenter struts that lock down the main foils .
I also ordered all the harken cars ,ropes, dyneema shrouds ,ss bolts nuts and screws to put on the deck gear and winches.
Hi Chris,
Just realized you have two rudders. How do you lock the horizontal rudder foils to the vertical? Curious, do you intend to lift the windward main foil when sailing?
It is not a cat, it's a trimaran foiler(A-cat hull, cut down A-cat main) with surface piercing main foils, that also will have the possibility to be fine tuned with linear actuators. I first looked at a mechanical A-cat style daggerboard trim I found in Poland(Exploder), with a timing belt going from side to side, but it is easier to turn a potentiometer. If the foils does not work the way I want, the platform is built to easily adopt to for example Vampire style T-foils, although it seems to complicated for me. Adding a sketch of the basic concept.
Since retirement I have worked with my boats, but time is the enemy.

Just had to link this thread in my FB foil group, address below

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Ah a return to Blue Arrow . I have an F18 HT bimare which I have retrofitted with exploder A3 foils multi purchase foil adjust and T rudders . Works a little scarey at speed downhill!! Only problem with the electric rams are their speed amperage demands . How are you sensing height
Weekend of fabricating and watching Danny tig weld. Ss torpedo for the trailer to support the keel bulb . And the ss hinging struts to lock down the main T foils . He has welded unp the struts but I need to clean up the threads for the heim joints .



Only problem with the electric rams are their speed amperage demands . How are you sensing height
Yep, the main problem. No need for other than fine trim of the main foils, as they are surface piercing and thereby selfsensing. But I will try a voltage sensing circuit that sets the main foils in center position when voltage goes below a certain value. After that the mechanical Waszp trim system for the rudder works(nose down lower main foil AoA, nose up higher).

I got inspired after seeing Doug Halsey´s Broomstick(1st image) and have got tremendous help from him with the foil configuration. Have had a pause from the build for a long period, but I am now on track again.

Interesting trailer modification. Might copy that, as I recently bought a trailer chassis to rebuild for my 16ft sport boat and two small trimarans.

Was about to use paulownia core in my foils(2nd image), but it is no longer available in Sweden. Found this epoxy foam with density PB 250 below and PB400 a little higher than Paulownias 0,3kg/dm3. Looks promising, have you tried it?
Sicomin foam data sheet

Sorry for all talk about my tri in your thread.



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