Keith
Guru
- Joined
- Oct 5, 2007
- Messages
- 2,715
- Vessel Name
- Anastasia III
- Vessel Make
- Krogen 42
There is no such thing as gravity. The earth sucks.
For the uninitiated that PBB would be Professional Boat Builder.FF wrote:
"Are you telling me there are millions of people flying airplanes w wings holding them up and we only have "theories" about how they work?"
Aircraft defy gravity (while they work) and there is not yet a good theory on gravity.
Or a good "Unified Field" theory that has any more proveability than "God did it!".
Just because we dont have full knowledge on a subject does not mean we cant build something.
This months PBB has a great article on a Dutch research lab , and their "new" cruising hull shape.
Sad reading for anyone looking for a "fast trawler" , even after 5000 years of boats , and a gang of Cray's working on the problem, with decades of tow tank observations.
"we only have "theories" about how they work?"
Anyone that is foolish enough to go in an Airbust may soon realize not all theories of flight will get you to a destination other than Valhalla..
FF
It's been my observation-- and from what I've read by marine architects--- that you are correct. I suppose you could force a boat like a GB onto a full plane if you put huge engines into it, but for the types of engines typically used in today's "trawlers," even the relatively high-power engines, they cannot force the hull to go fast enough to achieve a true plane.* The deep forefoot and keel of the typical trawler-type boat adds a great deal of drag, so a sort of plowing "semi-plane" is the best these boats can achieve.sloboat wrote:
It is my understanding that semi-displacement/semi-planing boats never really achieve true plane. While the hulls are designed to provide a modicum of lift, such that less of the wetted surface is below the water line, they never actually get on a true plane.