Why no aerodynamic control/stabilizer surfaces on high speed cats?

That the people at Monofoil have not mentioned the name of Bernard Smith as the originator of the lifting wing-hydrofoil concept is a terrible omission. Bernard Smith was sailing models of very nearly identical concept boats nearly 50 years ago.

 

Credit

Not the first time the originator of a concept hasn't received the credit due them.

 

Beyond just hydrodynamics

Now THERE'S a designer who understands a boat can be as much an aerodynamic craft as it is a hydrodynamic craft.

 

Glad you like it. I really hope this project succeeds, not just because it's British, but because it is such an elegant solution and very well thought through. I am actually quite confident about it's chances.

 

Monofoil

The models have gone like a bat.

 

Concepts

http://www.boatdesign.net/forums/showthread.php?t=15461

Aside from the Budweiser rocket car, the other major design influence on Lee Taylor's "Discovery II" rocket boat was the Sea Dart.

 

I had cockpit-controlled canards on my offshore race cat’s years ago, Aside from the aerodynamic trim abilities thinking was to give the crew half a chance at control should the boat ever become airborne.

 

Canards

You were ahead of your time.

 

125 knots on the ocean.... why?
For recreational or professional racing?

There is definitely no practical way to do this from a cargo delivery or military standpoint. If for boat racing, I think fast racing boats do have some aero incorporation in design.

 

125 knots on the ocean

Sea Dart did 125 knots on the ocean because that was its freakin' takeoff and landing speed.

Virtually all current offshore racing boats (unlike Unlimited hydroplanes) do not incorporate aerodynamic stabilizer and control surfaces, other than a flap on the tunnel of some fast cats used to a modulate lift.

 

Is this about boats or planes? If it's about boats, Sea Dart is irrelevant.

There might be a reason that control surfaces are not typically on offshore racing powerboats. Complexity most likely. They could probably cause as many or more problems than they would solve.

I think aero treatment is along the lines of keeping wind drag low.

 

Sea Dart is irrelevant only to those who think fast boats are watercraft instead of interface vehicles (vehicles that operate in the air/water interface).

Sea Dart was considered relevant enough by the designer of Lee Taylor's "Discovery II" to be used as a design source. How many 200 mph or 300 mph boats have you designed?

"There might be a reason that control surfaces are not typically on offshore racing powerboats." No good reason, considering that 200 mph hydroplanes have a wing, vertical stabilizers and driver-controlled canards. Putting them on hydroplanes created a lot more solutions than problems.

 

My point was a question. Why and where do you want to go 125+ knots?

If you are in the very dynamically unstable environs of the ocean, control surfaces can be a problem instead of a solution. For hydroplanes in calm conditions, control surfaces are acting in a much more stable state.

By the way, I have worked on high speed stuff for the navy, including surface effect ships, hydrofoils, and other radical concepts at high speed.

 

Relevancy

The question is moot. As in irrelevant.

Cats are going that speed or faster now.

The RELEVANT question is how to make them more suitable for those speeds.

Unlimited hydroplanes don't operate in calm conditions. They operate in choppy water churned up by skid fins and props blasting hundred foot long roostertails.

 

We're in different thought processes. What is the reason for going this fast with a cat? That will point to different approaches.
Also, our notion of rough conditions is different. Small chop from hydroplane skid fins is not what I was thinking of as rough. My thoughts were more on the lines of 6+ foot waves in the ocean with 20 knots of wind.

So I'm asking for a definition of the environment and purpose of the craft in concrete terms. Then solutions become more clear. Why and where?