New Hobie Design?

I only have the one photo. He would have to mail me a pic and I have not talked to him since last fall. I can try to call again and see what happens.

 

Thank you! Would be great to see a picture of the fast sailboat with the interesting bottom.
A friend of mine startet more than thirty years ago to develop fast sailboats and he is now developing ships up to 150m (492,125ft). Hundreds of tests (tanktests and CFD) have been made and boats (sail and motor) and ships built.







All his designs have a special hull -- with a slight hollow section at the bottom optimized from fn0.4 to fn1.2. His newest design is a 6m (19,685ft) Sailboat (for himself and his son when he will retire) which is very successful.



Hope you can understand my interest.

 

Manfred; the tunnel hulled sailboat is an interesting, but not a new, concept. That design characteristic has been around for some time. The inland lakes scow M20 is an example in the US. They work best when heeled to some predetermined angle whereupon the waterline becomes very narrow making the length/beam ratio favorable and wetted surface is diminished somewhat.

The tunnel hull is not comparable to the curious undulating hull in the OP, of course.

 

Yes messabout, you are right, the tunnel hull is an old pond. Maderform hulls are patented and - as far as I understand them - no tunnel design. They work best, when not heeled. Please have a look at posting 18: http://www.boatdesign.net/forums/multihulls/team-lalous-new-multi-50-trimaran-46659-2.html.



A simple similiarity at a first glance might be - if you cut the ZodieCat16 where the daggerboard comes through the bottom. The hollow section ( in the CFD paper "Dynamisch erzeugter Auftrieb" - dynamically generated lift - by waterflow: blue is suction, yellow to red lift) for me is the interesting (lift producing) part of the hull. Hope it is helpful.

 

Photo coming

I just received another call from Doug Harrison and he will send a photo of the boat that was fast. The boat in the photo was a mono-hull and he built it in 1958, tried to race it and won races. He says that it was very fast and that he knows the design will work because of testing.

I may just make a model and see what happens.
He also said he will send another photo of the boat. I will post when it arrives.

 

Great, thank you JHF.

 

JFH,
the post above talks about optimization for Fn 0.4 to 1.2

This is sensible that the wavy bottom could reduce drag BELOW HULL SPEED. The objections and misunderstandings are based on trying to figure out how it could be fast or win races. Fn 1.2 is extremely slow for a beach cat. The idea that a beach cat could win anything at less than Fn 2+ is inconceivable.

 

"The post above" (#17) is about MADERFORM 6. This monohull design is optimized up to froude 1.2 which means it is able to plane. The design is optimized up to 1.2, not limited to froude 1.2.
There is nothing said about the speed of the Douglas Harrison designs about which I would like to lern more.

 

The designer phoned me a few weeks ago and said that he would send the photo of the first boat. He suffered a stroke and I fear is not well. My other fear is that he simply wants his design built so that he can say that it works (or does not work) and he wants to simply submit his design as payment. If there is someone with time and a little extra cash who wants to build this boat, let me know. I have the drawings..

 

Scientific research

Here is an interesting scientific research of the body of the sailfish: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0081323 . This can be compared with the claims of Douglas Harrison. And: http://images.google.de/imgres?imgu...ved=0ahUKEwi2sv2cg4LPAhXF7RQKHSJ8DJkQ9QEIIDAA