You are using "asymptote" in a metaphoric, rather than mathematical
sense.



On Tue, 31 Aug 2004 13:31:46 -0400, DSK wrote:

Looks like it to me. It's just much farther to the right on the graph


Rodney Myrvaagnes wrote:
In neither case does it get vertical, as an asymptote would.

1- an asymptote doesn't have to be vertical (or horizontal) on the graph

2- if the power/speed curve does not go vertical (or approach it very
very very closely) then you're saying that the boat can reach infinite
speed. This is impossible, nyet?


In the case of planing boats, the slope of the curve doesn't even
increase everywhere, buty goes over a hump at the onset of planing.

Depends on the boat. Some don't have much of a hump at all.

"Hump" is kind of a misnomer IMHO... what happens is that the boat's
power/speed curve trends increasingly upward as marginal power increases
faster than speed, then flattens out again as it starts planing. It's
not a hump, more of a plateau or shelf.


But ordinary medium-to-light-displacement sailboats zip right past
hull speed when the wind rises.

Do they reach infinite speed?

You're right about fast boats zipping right past hull speed like it's
not there... that's why I always say that "hull speed" is not a hard
limit... also you have to consider the speed-length ratio (or Froude
number if you prefer) is not the same for all boats. Two different boats
(say, a J-35 and an Island Packet 35) should not really have the same
"hull speed" even if their LWL is exactly the same.

The power/speed curve of all boats... power, sail, diplacement, planing,
mulithull, whatever... trends toward vertical as the speed increases.
For some boats it's way to the right, at impressively high speeds. But
it's there!

Fresh Breezes- Doug King


Rodney Myrvaagnes NYC J36 Gjo/a

"Religious wisdom is to wisdom as military music is to music."