Professional BoatBuilder article: Foiling Outboard-Powered Catamaran

[ProBoat]

PBB editor-at-large Dieter Loibner’s report on Jan Brandt, his nascent company Matanzas Watercraft, and his cruising power catamaran with foil-assisted planing hulls and wave-piercing bows, the Matanzas 29. With design and engineering assistance from foiling experts Bieker Boats (biekerboats.com) of Anacortes, Washington, Brandt aims to deliver a projected 5-gph (19-lph) fuel consumption rate at a 20-knot cruising speed--a very practical compromise between efficient displacement monohulls of that size running at 10 knots and the current market trend of powering 35’ (10.7m) center consoles with triple 300-hp outboards. The Efficiency of a Foiling Powercat - Professional BoatBuilder Magazine https://bit.ly/2J6FZoF

 

[Niclas Vestman]

Wow! Awesome project. Thanks for a very interesting link!

 

[ProBoat]

To All, Sorry for the initial posting in the wrong forum. Thanks for moving it to the proper place. To Niclas Vestman, you're welcome! Glad you enjoyed it.

 

[Russell Brown]

I just got to check out the lifting foils yesterday. They are quite beautiful and don't weigh much.

 

[ziper1221]

Since crab or lobster pot buoys are not much of a concern in Florida

Uhh, I'm not real sure about that part. The rest certainly looks interesting. I wonder if there is any provisions for a controlled breakaway in case of a foil strike. Those rear foils could probably put a several hundred pounds of load on that lower unit, will there be any complications with that much force on a 90 hp unit? Any ideas why the foils were built solid forward, foam aft instead of a more typical sandwich?

 

[ProBoat]

Uhh, I'm not real sure about that part. The rest certainly looks interesting. I wonder if there is any provisions for a controlled breakaway in case of a foil strike. Those rear foils could probably put a several hundred pounds of load on that lower unit, will there be any complications with that much force on a 90 hp unit? Any ideas why the foils were built solid forward, foam aft instead of a more typical sandwich?

I've passed your questions on to the author of the article... answers to come.

 

[Russell Brown]

Everything in boat design is a compromise. Most boats don't like hitting things at high speeds, but lots of high speed boats have things like daggerboards and rudders that don't kick up. Now lots of high speed boats have hydrofoils and sometimes they break when hitting things. In this case, breaking a foil only means a slower trip home. That's how it seems to me anyway.

 

[Mr Efficiency]

No doubt about it, the best way to travel in the water, is to travel out of it. The flying-fish discovered that a while ago !

 

[Mr Efficiency]

What would happen if one foil sheared off through a collision with foreign objects, besides a sudden change in heading, I guess it isn't going fast enough to create a rotating force from the side still intact, that could roll the boat. I think I prefer foils inside the tunnel.

 

[ziper1221]

Everything in boat design is a compromise. Most boats don't like hitting things at high speeds, but lots of high speed boats have things like daggerboards and rudders that don't kick up. Now lots of high speed boats have hydrofoils and sometimes they break when hitting things. In this case, breaking a foil only means a slower trip home. That's how it seems to me anyway.

For sure, but it seems like some kind of shear pin arrangement could save a lot of damage.

 

[Niclas Vestman]

My only objection is cabin- and decksides (upper freeboard) design. Love all the rest of it. And I really get the design for market SOR. But in that case, design all of it for market. Sorry but the top sides/cabin are hideous. Actually remarkably similar to the fantastic but equally querky Gougeon 32. Looks like a motorboat version of it. Good as in an amazing boat and concept idea. Bad as in an uggly duckling design. Should be possible to make a redesign that has much more market potential.

 

[brian eiland]

Basic concept for weekender is good, but I don't think too much of this design,...list of concerns here,..
Weekender/Picnic PowerCat https://www.boatdesign.net/threads/weekender-picnic-powercat.33751/page-3#post-872679

 

[Russell Brown]

Brian, I read your critique of this design and I agree with a bit of it, but why would you criticize such a forward-thinking boat that was designed by people that know one hell of a lot about all of the compromises inherent in this kind of boat. This is a boat that is actually being built and will soon be tested, so what is the purpose of listing your concerns? Does it make you feel better somehow to dump on someone's best effort? If you feel strongly about this kind of boat, then make one happen. I won't criticize it.

 

[Mr Efficiency]

Any foils on a fishing boat, especially projecting out and down like these, are a bit of a hazard for fouling lines, guaranteed to cut you off when that big trophy fish takes a run as you try and bring it to gaff.

 

[Niclas Vestman]

Brian, I read your critique of this design and I agree with a bit of it, but why would you criticize such a forward-thinking boat that was designed by people that know one hell of a lot about all of the compromises inherent in this kind of boat. This is a boat that is actually being built and will soon be tested, so what is the purpose of listing your concerns? Does it make you feel better somehow to dump on someone's best effort? If you feel strongly about this kind of boat, then make one happen. I won't criticize it.

Because constructive critisism is about the best you can give anyone. In my opinion, if not directly rude, it is actually generous and shows interest and that someone cares.

Also the article mentioned it was a prototype build in a manner so that changes in the design can be made. Meaning no 100% finished design with molds. But rather a one of, in a slightly "economical" build. So the critique/suggestions I find are very appropriate.