The Displacement Glider

Stephen,

I don't see any edits on your previous posts.

You have gone much further with this idea than I did on my boat. At the point of commiting to sawing wood, a little conservatism seeps in.

My boat has:

A normal monohedron hull, DR =26 Degrees at 25% aft and 10 degrees at transom. Keel is parallel to static WL.

Chine flat angle of incidence = 1 degree to static WL

Chine width at transom = 12 inches

Displacement with two crew = about 2500 lbs

CG = about 40% fwd of LWL fwd of transom

Power = 50hp Yamaha

The maximum running trim occurs at top speed of 23mph and is no more than 2 degrees so that the chines are running at 3 degrees. The chine flats were originally considered to be like low drag trim tabs to promote early planing and prevent stern squat. I know that these numbers are not optimum but the behavior of the boat seems worth the price of more drag at high speed.

Wake flattens out at 9.5 to 10 mph and stern never squats at all.

I have wondered at what the result would be of mono deadrise of 20+ degrees with the keel rising to near the transom WL and the chine flats becoming full transom width. It begins to look a bit like yours except that I still considered it to be a low speed planing hull.

Based on my results, I'd guess that your estimates are conservative and that you will not need 100hp to drive this rig to your target speed, especially if you use a prop drive.

Don't hold your breath for the fuel cell to be generally available. When I graduated college in 1959, there were two technical marvels that were just around the corner: The fuel cell and the maglev train. Both are now reality but not for us plebes.

Tom Lathrop

 

Huh! funny how every time you see something new, you think to yourself - bugger nicked my idea!
A few months back I did a quick model of a hull for speeds in the normal semi-planing range. Won't pretend that the shape is all my own - the inspiration came from the hullform incorporated so succesfully by Malcom Tennant in his 'displacement' powercats. I though to myself, I wonder if that'd work in a monohull....
There's no refinemt done here - just the bare bones of an idea - but there's Stephen's boat and the displacement glider - and no doubt a thousand of Bolgers boats that have all done it before me...again!

 

Different idea altogether, but interesting none the less...

http://www.ybw.com/ibinews/newsdesk/20031105111151ibinews.html

 

I think this boat looks familiar

 

The more things change the more they stay the same. A lot of good stuff in them old books.

Gary

 

Stop squinting so much

here's the lines. I'll see if I can get them darker.