856-678-2186 - The online community for enthusiasts of trailerable (and cartopable) trimarans moreinfo@smalltrimarans.com

finns-on-triple-a-trimaran-4The Triple A Trimaran has now been modified a bit. Sailor / self-boatbuilder Hans Schipper optimized this craft after building his newer boat.

And what is the “coolest thing” about the modified Triple A? Well, its “finn,” of course. (See below).
Hans shares the following with us here, including info, pics and vids.

There is a good bit to think about with regards to what is going on when it comes to the finns now attached to the amas of this boat.

Let’s let Hans tell us about it.


Triple A Trimaran with Finns
By Hans Schipper

The experience of building the Cool Finn trimaran allowed me to look, with new eyes, at my previous creation — the Triple A trimaran.

The top speed of that boat (12 to 13 knots) is really enough for me. I just wanted more stability at 4+ Beaufort. I made two improvements: I reefed the mainsail and made hydrofoils in the amas.


It’s already quite cool here and I tested the foils today in 5 to 6 knots wind. My first impression is that the foils contribute to greater stability without loss of speed. I look forward to the next sailing season to explore the boundaries thereof.

What about the foils on the Triple A?


I made the wings shaped 45 degrees for gliding along the water plants. The adhesive wooden wing profiles are coated with two layers of glass fiber band which by means of a putty knife are filled with fiber-reinforced construction adhesive of Bison.

The fiberglass tape is available at building material stores and is used to finish seams between drywall. For my purpose it is also useful.


The wings are with this adhesive and fixed with three to four layers of fiberglass above and below the wing to the fuselage.

This adhesive gives some small bubbles during hardening so that you do not immediately have a smooth surface. So then sanding and updating with epoxy filler and finishing with two component paint is necessary.


I think that working with moisture curing polyurethane construction adhesive, from one pot, is a convenient alternative for this kind of job, instead of working with epoxy or polyester resin. The result seems no doubt strong enough.

Testsail of Triple A (video below) — with foils at 5 to 6 knots wind — at speed between 5 and 7.3 knots:

It was, again, a lot of fun … thinking, making and sailing. I’m looking forward to the new sailing season.


This winter, I’m going to work on a rowing system between the ama’s for the triple A, inspired on the foilsculler forward rower: