Most Interesting Small Tri

This boat was designed by Phill Maxwell and is one of the most visually stunning small tri's I've seen in a long time. Phill, any more info on the boat will be most welcome! http://www.amorousmarine.com/portfolioLp.php?catId=2

 

Those hulls look like they are designed to catch anything that happens to be floating on the surface so it can be dragged along with the boat -- unless it's a fishing net or something else that's not so easy to move, then maybe the boat will pitch-pole or come to a quick stop or do a fast 180 or ??? Otherwise it's an interesting design, I just don't think those bows make much sense in the real world.

 

To me, they simply look vertical, not pointy.

In any case, it's a beautiful boat. Now, install two high-peaked lugsails on that thing

Edit: On a closer look, you're absolute right.

 

Wave piercing design? Looks like a downhill kayak with amas to me...
Somewhere was a thread with the pros and cons of this kind of reverse bows (if they are, can't see it from the pic)...
Here it is: http://www.boatdesign.net/forums/showthread.php?t=22172

 

The main picture of the boat sailing in the website 'doesnt look right'. Is it short of buoyancy, does it need more waterline length or does the stern need running out? but the lad in the picture seems to be struggling. I wouldnt want to be out there in a blow......

 

Endorphin

I'm not sure you guys realize that this boat is designed to be a three foil (surface piercing)foiler. In the future the kid will be substantially above the water--and having the time of his life!

 

Thanks Doug, in that case it makes sense.

 

Ken,

All that you mentioned in the post above still holds true for the foiler version, should it ever happen. Just because you pulled the reverse bows out of the water, does not mean that there are still not serious amounts of leading edge, stuff catching, appendages in the water.

In fact, the whole design when in sea hugger mode is a veritable collection agency for what grows, floats and is placed by man. Now, just to be fair, I still see this boat as an interesting suggestion as to the possibilities for a rather spendy, recreational boat.

On the economy, self-built side of things... It must have been something like three years ago that I did a double version of a boat of this type as a design exercise, not really intending to take it to fully built status. Instead of fully flying foils, my design used the foils for other reasons. I was looking to give the boat controlled pitch modulation with the foiled rudder and the foils in the amas were much more like, semi-Bruce foils, that gave the boat some degree of lift while providing an assist to the fin keeled bottoms of the amas for Lateral Resistance.

The ama-mounted foils do not remain deployed for normal sailing. Instead, they fold up and into the amas, much like centerboards on a main hull. If they encounter any underwater obstacles, they can rotate up and out of the way. This is also an excellent strategy for weed shedding, should you sail into waters of that type.

The T-foil rudder setup is different for the typical version of this technical strategy in that the horizontal foils would be swept back, also for weed shedding, while still providing a good deal of pitch stability.

The whole package was meant to enhance the sailing function while not fully entering the realm of a purely foiling craft.

The design was shelved as a, to-be-built, development model that could potentially compete in the Watertribe Everglades Challange... to be possibly resurrected at some later date.

The images are posted below.

Chris Ostlind

 

One thing I've not seen anyone mention is the beam required to make diagonal daggerboards effective. The force from the board is at approximately right angles to the board. Project that past the c.g. and see what kind of righting arm it is, compared to vertical force from buoyancy on the amas.

Another way to look at it is the horizontal force component from the board is the same as the horizontal force component from a vertical daggerboard or centerboard - that component is dictated by the sail trim. The vertical component from the center of effort of the board (approximately mid span) is considerably inboard of the ama, representing a loss of effective beam.

And if the boat lifts out of the water, the center of effort of the boards moves down and inboard, making them even less effective with regard to righting moment - just when you may need more righting moment as the apparent wind strengthens and moves forward as the boat accelerates.

All of the concepts shown above have "normal" looking beam, with the daggers projecting inboard. If you want to preserve the righting moment as you add diagonal foils, the foils have to be mounted outboard, like those of Mark Pivac's Spitfire 12:


Or you have to build in extreme beam, like Hydroptere.

 

Chris,

I think your semi-foiler concept is far more appropriate for the average buyer. I like the configuration of your foils too, the ama foils are self-adjusting and self-balancing (I've seen the term 'surface-sensing' used before although I'm not sure if it means the same thing) which makes them more practical for the less 'gung-ho' crowd.

 

foil angles

Or you an mount them this way (here they are both lifted while at anchor) but when sailing, the faster you go the wider the boat gets - opposite of conventional foil setups, you gain more stability, not less.

 

I like the Hydroptere solution-or Gary's . Hydroptere:beam 1.36 X length(LOA 59'; Beam 80').
Gary thats one cool boat -any details?

 

This is the first foiler to win a race in the Moth class-7' beam 11' (+rudder gantry, if any). The boat in the water belonged to Brett Burvill; the other is a view of the foils on a similar boat:

 

angled fpoils

hey Doug
Thought I'd posted details before: Groucho Marx 11.3 x 11.3 metres (37 x 37 ft.), weight 650 kgs, wing mast 15,5 m x 0.5. One other point with angled out foils as compared to inwards sloping, you do not have to have an extreme beam like Hydroptere - less beam, although still square on Groucho, results in less weight and less bending loads. Be careful rounding marks or anchored yachts though!!