Foiling Trailer sailer

Today Danny and I finished the mainfoil locking struts more or less.
I then played with mainfoil flap and with the help of Eric put a carbon reinforced gudegon on the side of the rudder boxes so I can cut a slot and insert a heim joint for the rudder cross linking tubes





Trailer work with more to come to support torsion bar separate axles so the keel bulb can slide up the 10 inch ss gutter. i also cut the bottom off a 30 lb propane cylinder which I will use as the crucible for melting the lead .


Interceptors made for the rudder foils just need carbon vacuumed over and faired. Slots cut in side gudgeons on the rudder boxes. No sig voids .
made up foam interceptors for the mainfoils and after discussion cut them off. Whilst good for drag they would likely be a real pain interfering with sheets for the FRO and the kite plus the sails themselves. I can always put them on later but I suspect cavitation delay will not be a major concern!!
only problem at present is after 10000 to 13,000. Vertical feet of skiing each morning it is hard to find the energy to do more boat work at night ok in afternoon .I think I got as much done on the boat per week before I retired as I do now.What a problem to have !!



Chris you need neighbours to complain about the noise like you had in Freyberg Street. You have retired wow, then again I retired last year so I guess we are all getting on. Good to see you are still tinkering. Interesting project.

huey 2

Super Anarchist
From The Front Page

you guys following this?

February 15, 2023


I wonder if any of you may be interested in my 7.5 m foiling trailer sailer project. I know strictly speaking it is not a sport boat but it does have twin trapezes!! And headroom for short people! And I could use some help sourcing a 150-175 kg keel bulb and a 9.5 m carbon mast.
7.5 m long plus 350 mm boarding platform 2.5 m wide, draft 2.0 headroom 1.75m sleeps 4 nominally light displacement 850 kg sailing 1100 with 2 crew 115 kg !!! 2 Invert T hydrofoils with 35% flaps and 2 t rudders with variable AoA like a moth or maybe like an A class. Sail area main 20 m2 jib 13.2 m2 Fro and kite to be determined.
Construction is 6 and 9 mm ply over stringers with 100 gm carbon biaxial inside and 300 gm carbon biaxial outside with 100 gm glass cloth on the outside. Plywood 1.5 to 4 mm with high-density styrofoam 60 psi and carbon for the bulkheads and berth tops and sides. galley and loo similar construction .cabin top is carbon styrofoam 60 psi carbon with Foam replaced with shear webs and uni carbon caps.I only wish Julian B had started his 89er sooner and I would have reduced a lot of my laminates and used more Basalt and pet foam. However, I got the carbon really cheaply. Currently weighs 520 kg with all interior in place and most of the fairing done.
I have been working on this for 2.3 yrs so this is slow going for me after building the NZ tris Dragon and Timber Wolf much faster . Guess I am getting old, but it is taking longer than building Free Radical 10.5 m cat .
Jump in the thread!
Thanks for touching base Murray .I thought my neighbours were surprisingly supportive in Tauranga with all my projects !! Pretty good here too but no local marine stores and no other boat builders to bug .
Returning to the warmth 17C in the garage I have carbon uni reinforced the attachment of the tillers to the rudder boxes . I am also playing with the filleted sockets for the foil intersections. The rudders will have interceptors and the mainfoils initially do not.
I have received all my rope for running and standing rigging . I ended up using Binnacle , Marine outfitters and maple leaf ropes so that I could get the colors I wanted in the right material at the best price .
I also required another small order with Alllen brothers for blocks and cleats to adjust the rudder boxes and to hold down and raise the main foils .
A bigger order of harken cars and sliders was included with halyards and Dm20 standing rigging from Marine outfitters. We then shipped the harken cars off to North’s Vancouver for the mainsail.
I will start splicing soon in the evenings after I review Julian B approach and start work on the mast . Fortunately I have enough space to do that in the garage .




Super Anarchist
Sydney mostly
A bigger order of harken cars and sliders was included with halyards and Dm20 standing rigging

If ever I thought DM20 would be an issue in the standing rigging, it was yesterday. We all had 50-60 litres in the boats by the time we got back to the dock and as commented elsewhere we had 18knts of BS under main & jib only with green water over the bow. I think we were just shy of 20knts max speed so the loads down the M5 DM20 as we bore away would have been well over a couple of tonne. No decernable creep. And if I do need to tighten them up 10mm, (which I may because we drop the mast back 15mm) then it's a 30 min job, could even do it with the mast up.

Not saying the way I do it is perfect but it has worked.
Fiddling along learning. How to tig weld and grind out the cockups . Fortunately Danny mostly fixed the mast base pivot ,vang and halyard block attachment Left front of middle photo. I also had to make up an external chainplate to allow 3 rigging screws per side to attach to to the singular carbon eye . I was planning on doing a ring with lashings for D1 V1 and Top mast but having seen Julian’s B rig on DP I feel I need much finer adjustment . With hindsight. 3 slots in a longer carbon wrap chainplate would have been better and much lighter .
cruxiform piece of welded ss tube will get filament wound to become the gooseneck pivot.
rudder boxes are slowly fairing up as are the fillet sockets for the foil intersections .
I also cut the spreaders to length and angle.
The biggest problem was a week of small recurrent snow falls totalling. 70 cm over 7 days.The white elevator is hard to resist but now we are off for 3 weeks circling Mt Blanc in Italy and France .The snow may not be as good as here but the wine and food should be superb and we both need a holiday.



I’m loving following your build Chris since finding the sports boat forum on SA. Now that Julian’s weapon is sailing I’m looking forward to seeing your boat in the drink.
I remember reading about Timberwolf several years ago and was impressed with its design. I’ve spent years myself building and racing trailerable tri’s and cats sometimes against sports boats(usually in the bay to bay in Queensland) and being impressed with their speed, especially Vivace one of Julian’s designs which we couldn’t beat on corrected time on my cat Pork Chop(unless they got caught up on a sandbank or two).
I must admit your’s and Julian’s technical knowledge is light years ahead of mine(I’m more of a visual mathematics designer 👩‍🎨 ha ha). Do you have any idea approximately of the launch date?