New Rowing Trimaran

You might recall that my Formula 40 catamaran hull lines held the world record for fastest rowing across the Atlantic last year. For a day. I did not know about the rest of the design, and a lot was wrong. I insisted on being fully involved with the next boat. Crew of 9. Here it is.

Rower 60 Trimaran


Main hull has L/B of 21:1.  Displacement of  4848 lbs.  Hull speed is 11 knots.  At hull speed it takes under 6 hp to move at that speed.  At that speed there is 265 lbs of form drag and 125 lbs of friction drag. Draft is only 12” so change in depth over the trip should not change much, keeping waterline long.

 X bow allows less hull area, reduced windage and significantly less wave pitching.  See video at

  Next year everybody will have these bows.  Flare is high enough above waterline that it should not increase pitching.   

Total main hull max height is 6.5’.  I say that the governing load will be a wave on each end and the middle in the air.  The flare also helps restrain buckling.

Curved openings are much stronger.  Upwind I would cover openings with Eisenglass or thin acrylic like man-powered craft record holders do.

Top will have solar panels and flush hatches as needed.

 Amas are just under 17’ long and 1000 lbs displacement reserve.  I see greatest load being pushed sideways 20’ by a wave.  Location aft helps minimize pitching again as it spreads out the centers of buoyancy. 

I assume beam should be completely rigid, like in bicycle racing where flexing frame is seen to absorb power.

I see this as having every possible thing done right.  I don’t know if 5’ tall above waterline is too much.  It does give more beam depth.

—–Original Message—–

11 thoughts on “New Rowing Trimaran”

  1. What does “hull speed” mean in this context. Racing 8s have a hard time getting to 11 knots for any length of time. How are you going to do that with a quad that weighs early 5 kip? 7 knots maybe 8 more like it–and that with some real output I would think.

    Taking your numbers above, I see EHP = 13 hp. (265+125)*6076/3600 *11knt / 550.

    Your efficiency on the oars is what? Let’s be kind and say 60%. So “shp” = almost 19 hp. You have four humans…

    Real output on long term of athletes more like 200 watts—or 1/4 hp so 1 hp “shp” for the system…

    1. Hull speed for this unit is just over 10 knots. At full load condition, Prolines says it needs about 8 BHP. At lightship of around 2000 lbs it needs 2.3 BHP to go hull speed according to Prolines. I can give it as little drag as possible. I can’t do much about the power side. More on this unit soon.

    1. Was my original idea. And proa could squeeze through a smaller hole in the waves. I was happy to get the X-bow and hard-top approved. Next one will be proa.

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