1514Re: Present "box keel" designers?
- Apr 2, 2007"I think Dave Gerr got it right.
Seabrights were never designed to go that fast. Atkin warned about
trying to drive them faster than their design speeds, and he had good
reason to do so.
Gerr in TNOB claims there still fine at SL 4
For a 36ft lwl that would be 24K ,,fine for me as it should be doable
in such a skinney hull at 8gph.
"I have read that once they exceed the design speed envelope their
hulls do not trap the wake like they do at their design speeds, and
this adversely affects handling.
In other words, running them faster makes them dangerous."
The only MoTorBoat article I have that talks about a boat run with a
2X sized re engine found the stern continued to lift , and submerged
too much stem , causing bow steering.
Atkins solution was simple strakes that lifted the bow , to maintain
the same attitude at the higher speeds.
Chine strakes cost HP to work, we are considering a trim tab set ,
that would work backwards from normal.
At low and medium speeds the tabs would allow the standard Atkin style
stern lift from the aft section.
At higher speed the stern could be lowered by opening (closing the
tabs) the aft outlet and not immersing the bow to excess.
At very high plaining speeds ,I'm sure the std V bottom with big dead
rise would work fine , but 24K is not a very high speed as SL4 is
still in the Semiplaining regime.
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