"John Cairns" wrote in message
m...
| The "theoretical" nature of the calculator relates to hull shape/wetted
| surface, which it doesn't account for, and waterline length, which
changes.
| It doesn't consider if a boat can plane, which is an entirely different
| ballgame. It does offer a pretty close estimate of how fast a displacement
| boat can travel, power or sail. If the calculator wasn't fairly accurate,
it
| would be pointless, wouldn't it? Are you saying a CR38 can plane upwind? I
| would find that extremely hard to believe, considering hull shape and
| displacement. Now I have seen the calculator with the addendum that it
| applied to boats with D/L ratios of over 150, but again the author was
| referring to the ability to plane. The CR38 has a ratio of 359, which
makes
| it well over 150. I think if you quiz any NA they'll agree. Not my ideas,
| just passing them along. Will a CR38 exceed it's theoretical hull speed?
| Sure. Will it exceed it's theoretical hull speed by 50%. I don't think so.

John ... at 11 kts it's only 3.7 kts above it's hull speed. I said it was
upwind but never said it was a close reach. Really John... you've been on
the ocean. I get a 42 mile passage in 5 hours from dock to dock on my 30
footer in seas that crest at 12 feet plus swells, gale force at 34 kts wind
and gusting..... big deal. That's not a big stretch!


|
| " The slowest the CR is, is into the wind in heavy chop, 4 to 8 ft seas
| close together. The boat does not ride up and down them, it kind of goes
| through
| them, EACH WAVE SLOWING THE BOAT DOWN. I find it best to fall off some
and
| power up the sails, it gives a nicer ride but slows your vmg to 3 kts or
| so.

Okay.. but I was describing a crossing of Yellowbanks... which has no such
chop. I think we all know the effects of chop and confused seastates.

|
| "No we don't normally need to reduce sail until the gets around 25kts. I
| recently left Lemmington in Canada in 25 gusts to 35. We had one reef in
the
| main and staysail. We averaged 6.8 kts for 6 hours to Huron,OH and were
very
| comfortable."

I can claim likewise performance for my 30 footer.

|
| Now I don't know what direction the wind was coming from, but even if the
| wind was on his nose, he wasn't doing 11 kts. Could he have done 11 kts.
in
| a planing hull? Probably, but I don't think he would have been very
| comfortable, either. And considering the probable sea state-by the time he
| reached the half-way point the lake would have been fairly choppy
regardless
| of the wind direction-6.8 kts. is a pretty good speed.

Fine John... you described a passage with minimal input. Of course he wasn't
doing eleven knots .... he stated 6.8... which is rather slow considering
that would equate to my average speeds in good air.
In 25 gusting to 35 that boat will sustain 6.8 easily even with a good chop
to weather.

Look John... these boats carry amazing momentum.... enough to reduce chop
to insignificant equations.

CM