Category Archives: multihull racing

More R2AK in Seattle

This Melvin and Morelli tri was hauled out recently in Seattle. It is intended for the R2AK race this summer.
I understand that it is all carbon fiber, which can make it light. And the amas look full length, which is good.

Now, I am assuming that the first 3/4 of the race after Victoria will basically be like sailing in the San Juans in the summer.  Light, shifty air.  Short tacking, and again, and again.  Through kelp beds.  Crew on the leeward side to drape some shape into the jib and pull the wider main hull out of the water.

If I may, those amas look to me like they were designed for tradewind conditions, not 4 knots true.  They look like they were designed by someone who had never sailed in the San Juans in the summer.   The fat waterplane down low is draggy in light wind.   And why don’t the amas join at the inboard side, instead of the middle.  That would save weight and make the beam and the join stiffer.

I would offer them some improved amas that would increase light weather speed compared to these.  They could slide right on, and even improve the BOA.  I won’t hold my breath.  With the MM plans costing 10 times what mine do, they surely have Stockholm syndrome and will ignore the physics.

 mmama2r2ak

mmamar2ak

 

 

More R2AK

I keep seeing more earnest, helpless, odd entries to the R2AK race. People, if winning is of any interest, and from what I have seen, maybe it isn’t, you need something like this. A modern tri. And compared to the cookie cutter F-tris;  its much wider overall for the same length; it will stay more level, spilling less wind. Round bilge will tack faster. No struts to douche the crew in waves. This was designed for Simmo before he dialed back.  Add some oars and rock and roll.

27PSP3

Dragonfly Rolled (the Seattle one)

The local Seattle formula 40 catamaran Dragonfly capsized during the Cow Bay Regatta. Not my design.  It was originally from New Zealand and was originally named Simply the Best. It’s owner Pat is one of the best sailors I know.  I hope to find out more soon, but I was told that it rolled over on a reach after stuffing into a kelp bed.  It was a heavy air day.  If it could happen to Pat, it could happen to anyone.  I see the boat is on the hard in Everett, sans mast.  Pic is on happier days.

dragonflycat

 

More Stuff Done Wrong?

An ama bow broke off during the race.  70′ trimaran? Clearly the only time we get to see inside.  Most of us.  Picture below.

Its time again for speculative forensics.   One would assume that if they going to spend a couple of million on it, everything would be perfectly engineered.  I learned long ago that just because they are famous or expensive, it doesn’t mean it was done right.

And again, I can only go off of what I can see here.  If anyone knows any of it first hand, let me know.

First it sure looks like a carbon fiber keel and a carbon fiber band running down each side just above the stringer.  Rule of mixtures error if so.  If you use carbon for global loads, there better be enough of it to do the whole job. Regulars here already know that the stretch to failure of carbon is around 1%.  The other fabrics have much more stretch.  So the carbon would have to fail before the other kinds would begin to help much.

I would not have used a stringer.  They increase the panel aspect ratio, which is weaker.  The closer to 1:1 a panel can be, the better.

That core looks really thin to me.  It looks like 12mm but am sure it couldn’t be that thin.  I would have had no less than 25 mm and maybe even 40mm thick.  I forget what colors of core denote what density.  Maybe someone has it handy.

Finally, that hull skin fabric sure looks like e-glass, or more likely Kevlar.  Dude.  That has already been covered.

They could have called me.

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Race To Alaska

Interesting event.  Tracker link http://tracker.r2ak.com/

I see that the two most heavily media flogged boats, the Bieker proa and the little cat from Port Townsend have dropped out and never did well.

It really only looked like a very long Shaw Island Classic to me.  Agility would be far more important than speed as I see it.   The wind will be from 10 different directions in 10 minutes and you may have to tack 5 times in that ten minutes to dodge eddies or kelp beds.  And typically it all seems to be uphill.  Short tacking is often the rule.  In this kind of race I expect that the old 34′ Smoholla might have been quicker than the F40 Geko.  Imagine having to move the mast every tack as on the Bieker proa?  What were they thinking?

That says 30′  or so trimaran to me.  They tack faster than the cats.  You see it firsthand at races in the San Juans.  And with all the kelp I’m sure a foiler is off the menu most of the time.

And when there is no wind, I learned in the Tasmania race that you can move a small multi pretty well rowing.

New Stiletto Catamaran

I was approached, along with the rock stars, I was told, to propose a design for the new Stiletto 10 meter catamaran. A kind of cruiser/racer with the iconic canopy as a kind of trademark. Said he had been in the Gunboat and J boat projects. The design brief was a bit unusual. It needed quick set up but must have no crossarms. The cockpit must be the crossarm. I did not know how that would work forward. I proposed Rafi’s fold system. Developer was not impressed I guess.   I put standard tubes on it for now.
The rest of the design brief was to be like an M32 with a minimal interior. Begs question why not just have an M32 if there will be no interior? My flared hulls would allow a pair of doubles and keep a skinny waterplane for speed.  I know nothing about marketing, but am sure it has always been true that if the toys are not shared, many of us would not have the toys.
It could have been simply trolling for ideas. I have had that happen several times before.

So I did a couple of quick models.  M10 is pretty straightforward.  M11 is very wild with defined edge lines.

m10PSP2

and the wild one

model11PSP2

Today at CSR

Pic of the 26′ Bieker proa at CSR today. Main hull is 3mm or 4mm ply with rounded chines. For race to Alaska.  I cannot understand the 80’s constant camber aesthetic with big overhangs and high bows.  More pics once I find the cable from phone to here.

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