new member. . . new tri


First time poster . . . been watching from the sidelines, but thought I would finally post and share what i’ve got cooking so I could then ask some of you some questions.

Recently, I decided to get off of my butt and finally build a model tri. Been a monohull sailor all my life, but with the 50 knot barrier getting ready to fall, I thought it might be fun to start sailing something a little faster. I thought I would start with a tri, and than use that as a platform for other things such as a foiler.

So, here (attached) it is, the trimaran I am currently working on. I will post pictures at a later date of the progress that has already been made on the hull plugs for both the main hull and ammas. Needless to say, I don;t spend too much time on the computer, so my posts are likely to be few and far between.

Lets hope the attachment worked

Y-N-T … WELCOME ! :smiley:

Please keep building and updating. We keep looking for more members and owner/builders to help demo these boats around the US. Only by showing their potential will other decide to join and build to the class size.

What size is the boat - 48 inches long, 39 inches long, or something in-between.

Post questions as they come up.


She is designed to be 48" but could probably be scaled. Most of my questions are about foil placement. I know where to position foils relative to the rigs center of effort on a monohull . . . .do the same rules apply on multis?

As much as I love a nice modern IRC Monohull (scale version of course) That is a pretty sexy rendering.

A few quick questions for the tri community (mainly Dick)

Is there any ballast?
Can an RC Tri capsize?

You guys have me intrigued. I am very fickle with my projects so who knows if I will ever get around to one, but this at least has it on my radar.

Heck . . . if you wanted to see sexy, I should have taken a couple minutes to throw a waterline on the main hull and render it in real colors against some environmental map in the CAD environment. I am amazed what computers can do these days.

My only reluctance with this trimaran project is that it feels like 3 (or more) times the work of putting together a monohull. Three hulls and cross beams compared to one hull . . . but I guess I dont have to worry about the ballast on the keel

If you stay with the monohull rig/keel locations you will be pretty close, although if I sail with a fractional rig with jib half size, I have to move the rig slightly forward. Remove the jib altogether, and you will have weather helm since removing the jib removes any lee effort in the entire rig. Going the other way, as jib size increases, I need to slide the rig aft to compensate for more sail forward, thus more lee helm. I would suggest a rig location further aft than mid-point of hull for two reasons.

  1. There will be more bow (and lever) forward to help reduce forward pitchpole.

  2. My 1 Meter just seems better balanced having moved the rig aft by almost 2 inches.

For Millrtme:

No there is seldom ballast in a trimaran, but some have fooled with movable ballast on a cat configuration - usually trying to emulate crew weight on scaled beach cats.

Yes - capsize is there waiting to happen. It can be lessened/avoided by:

  1. Deep reaching downwind rather than dead-downwind.
  2. A fast sail winch to allow mainsail to be dumped if a sideways capsize seems evident.
  3. An overall narrow boat which seems to reduce forward “tripping” but increases sideways tipping. Usually you can head up with rudder if windward hull goes airborne, and then still have winch ready to sheet out if it is still getting away from you.
  4. Gybing with main near centerline if possible, reducing sail area exposed to wind, but sheeting out and heading up slightly as boom swings over.
  5. Rig further back with more hull forward adding as a resistance to mast lever action.
  6. Using smaller rigs and not being “macho”
  7. Using lower aspect sails keeping sail area lower. (but doesn’t “look” cool)

and if more safety is needed, an aerodynamic shaped piece of foam at top of mast to prevent turtle if it does go over.

Nothing prevents using a weighted keel to learn and get the different feeling for sailing one of these. It will act as training wheels while you learn how to react. Can’t be watching the young ladies around the lake - the boats require 100% concentration. Weight on keel will help slow things down, and when comfortable or in light air, can be removed for only a dagger-board without lead. For day sailing, a weighted keel isn’t a bad idea, but obviously for racing, the added weight could make boat slower - but then being able to actually finish a race is important too.

Unlike a monohull, a lead keel will not recover a flipped cat or tri, but it “might” make it happen slower or less often as you learn.