Triton Mini40 build

I purchased hulls, beams and appendages to build a Triton a while ago. The Triton is a trimaran very similar to the Ghost Train. I started the build and have completed the raw boat less the rig in less than a week now. The parts did fit together very easy.
Most of the building time so far did I spend incorporating a long mast and fin box to play around with different mast positions.

I will filler and paint the boat soon and hope to have it in the water by Christmas. I’m excited how it will sail compared to my other trimaran.


Hey Roland, what a beautiful tri, why paint her?, she looks great as is!

Hi Roland -

“normally” I appreciate and like the looks of a fully sponsored big multi that is reduced in size to the Mini4/F48 scale. Having a multi with sponsor’s logos is like having an IACC boat decorated in their colors. Without coloring, the hull and sails become rather “blah”.

As I said “normally” - because in this case, if you are able to carry forward the translucent “look” without paint, I must agree with Niel in that it has a kind of “Ghostlike” look - and I guess it should if it is an update of the original GHOST TRAIN lines that was a leading design for so many years. There have been times when less is better, and from what I can tell in the photos you posted, this might be one of them.

Congrats on a great build. If I am correct - this is the “kit” being marketed by “Siri” of and he has pumped out a lot of “kits” for both mono as well as multi hull boats.

For those who might have an interest in building this one - it is 1220 cm wide with an overall length of 1200 cm to allow a bow bumper add. (That is 48 x 48 inches for U.S. sailors - virtually 1/2 sheet of plywood for relative size). The kit has the floats, main hull, and two cross beams, rudder and dagger-board/keel. At $720 for the kit it “seems” kind of expensive, but given it’s huge size, once you get a Mini40/F48 platform laid on the floor you can appreciate the reasonable cost. True you will have finishing expenses plus a rig (swing or conventional) but in the end, you should have doubled the cost in final value. Without a chunk of lead to add weight and slow it down, there aren’t too many on-the-water-boats that will be equal in outright performance.

Roland - Please continue to post additional photos as you continue your build.

Regards, Dick

Hi Niel,
Leaving the boat as it is now would be nice looking too, but with the strong sun here it would be bad for the epoxy. I certainly will have to paint the boat - my plan was a yellow or orange paint scheme to have good visibility of the boat on the lake.
As Dick already suspects I ordered the boat from Siri. I’m living in Thailand, this makes it easy for me to get hold of one of Siri’s boats. I have some other boats from RC-Sail already, they are well built and my orders were carried out in a timely manner.
Next weekend I will continue on the boat and will post updated pictures as soon as I have some.


Hi Roland,

Painting the boat in any color other than white or an off white will increase the internal heat, which may also have an effect on the epoxy if it is not made with a post-cured resin. All hulls generate condensation inside (cold water against the hull and the deck heated by the sun) but not many are aware of how much is generated. It can be considerable, and can be misinterpreted as a slow leak.

A semi-clear hull will help you keep track of condensation buildup before it becomes an issue for your electronics. There are lots of UV inhibitor clear coat choices on the market here in the US, I don’t know about where you are. So clear may be an option.

However clear may be hard to see at a long distance, so that is a downside. Anyway, I would definitely find out from Siri if he used a post-curing resin and if he did the post-curing. And I would initially go clear. If it is too hard to see or you have other worries then you can always paint it with a solid light color.

Roland -

Niel makes a good point about internal pressure from sun. Even on my big catamaran, I drilled a small vent hole at the top of the stern on each to allow pressure relief. A friend built a thin ply 5 meter catamaran, painted it dark blue and while in the sun, interior heated up and broke the cross supports when hull expanded. Hard to believe there is that much pressure.

On our r/c versions, “Normally” there are holes for sheets to run through or the hatch doesn’t fit tight - but for floats, I think I would drill a very small hole at top of floats if you build hollow. If you leave foam inside there is much less chance of hull expansion.

Are you the same person with the other trimaran painted orange with yellow “tiger stripes”?

Hi Dick,

No, that other gent is Ian Holt - who was in Shanghai, but has gone to Australia by now.

Thank you Niel and Dick for the advice and tips,
I have to agree that internal pressure can blow up the hulls if the boat is left in the sun without a proper vent. This is an issue even if the boat is painted in white. I will drill small holes in the stern of the floats. I will need them anyway to drain the hulls.
I am unsure about UV inhibitors in the clear coats available here, I have made up my mind to paint the boat in white. I have cut several new holes into the floats and made further modifications, now painting is a must.

I have glued an array of tubes into the floats to experiment with V-foils.


I have taken some more photos today.

No, it is not a Spaceship it’s a Trimaran.


Before you get too far I would suggest the foils in your floats are too far aft. If the foils are aft of the c/e of the rig then they won’t be able to lift much as the boat want’s to pitch over them all the time…

I’ve attached a picture of my tri with float foils for reference. You can just about tell where they are but it was the only side on pic I have of it!

I agree -
they are far too much aftward.
Floatfoils need to be placed right behind the forward crossbar to work properly.
Otherwise they lift up the sterns of the tri instead of the bows,
therefore pushing the bows down -
which you definitely will not/wouldn´t want to achieve.

For further explanations/understanding of the involved forces and especially force vectors please read:
the posts/pictures/drawings of Idealist - which is of course myself - and the plans of Nigel Irens!

For a Mini40 Trimaran the mast and the mainhull centerboard (if you use one) it is true,
that they need to be placed further aftward.
Mast at 50cm from the stern and centerboard right behind it,
instead of 60cm from the stern (what would be scale) -
but asymmetric floatfoils need to remain at their scale position.

Once again - this is due to the scaling factor of the involved force vectors at this size.
Sorry that I´m unable to make the physical reality less complicated -…-

Ernst Zemann/Idealist/Disabled

Dear aardvarkissues & disabled,
Thank you very much for your tips for the floats. I do not have any idea yet where the foils should be. I use symmetric foils, the position shown in the picture is about 30mm in front of the mast. I do have another 4 forward positions prepared in the floats to test.

You can see the array of foil tubes in this picture.

I already own a Nightmare MK8 and a 65M trimaran, both designs from ‘disabled’ - they both sail great. I have seen the Triton performing - it is fast but not easy to sail. With the Triton I’m looking for some challenges to civilize it without loosing the Triton’s performance. The Tri was intended to serve me as a test bed to play around with various mast positions, fin positions and fin shapes. Meanwhile I got the foils and the T-foil rudder from Siri for free to test them, so I upgraded my floats to accommodate the foils too.
Referring to your tips I will start my trials with the foremost foil position.
I hope I can get the boat into the water before Christmas and will tell you the outcome of the first tests.


None of the competitive mini’s I’ve raced with/against have the rig that far back. I think mine is 59cm from the stern.

The CLR of the float has just as much part to play in rig position as foils and putting the rig this far back will cause added drag as you have to compromise the rig and foils to get a balanced helm.

Oh Lord!
Before I could get a boat into the water before Chirstmas, I would definitely need to chop up some thick ice! ggg
Where is my flight ticket to Thailand? I thought I had one laying around here somewhere -…-
Makes me feel a bit jealous -…-

Keep up the good work, Rolando!

Just board a plane and bring your ice with you, it’s damn hot here


Over the weekend I have matched my rig to the boat and installed the hardware to keep the foils in place. Now only RC installation is left to do - I hope I can launch the Tri before the bananas in the background of the photos get yellow.

After the first sailing trials I will decide on the color for the boat.


My two bits again: Rig looks aft in relation to the foils, may have weather helm.

Swing rig could be lower, as in deck sweeping.

The swing rig spar that the jib pivot attaches to does not need to be angled upwards (the reason its done on monohulls is to keep this spar from digging into the water if the boat heels to windward when broaching). Having this spar horizontal will let you lower the jib down to level with the main foot which is the more ideal configuration.

Okay, thats three bits…

Dear Niel,
thank you for your tips and opinion again.
I also think the foils are to much ahead but I followed the ideas of aardvarkissues & disabled who both seem to have tris running on foils already and have recommended me this configuration. My Triton is my test bed to experiment with. I have build in the supports for 6 different foil positions I can move the foils backwards and the rig in front.

I will lower the rig a little bit more as soon as I have found the optimal position. I use this main hull as a test bed for various fins and foils, the fin cases are below the mast box and so the pivot tube for the rig is quite short already.

For the swing rig , I have used on my other Mini40 Tri already - the front spar is parallel to the deck. On the photo it looks otherwise seems to be a problem with the perspective.

Here are two photos of the rig itself.

Can’t wait to get the boat into the water


Dear Rolando,

  1. Your boat looks very good!

  2. As we say here at Austria: “Too many cooks will mess up the meal!”

My datas about mast-, centerboard- and foil-position are based on the experience
with my own boats with their own specific hullshapes and their performance.

The Triton is quite different.
So the best thing will be to figure out the best configuration for your boat yourself.

And I will be very pleased, if you share your experiences with me/us then.
Even if you tell me that my suggestions where wrong for your boat.

The truth is allways better than some kind of comfortable illusions
and/or second hand experiences from a distance.

Just my five cents

If the Triton is based on the Ghost Train (and it looks a lot like one) then your rig position is between 5 and 10cm further back than the original cad drawings. Not sure if this is something that you have done or if the boat came to you with that mast position?