"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

Yeah, I have been on the ocean, sailing up the stream, in a 47 footer with a
LWL of over 40', AND a phrf rating of 54, by all accounts a fast blue-water
passage maker and we couldn't average 11 kts. Sure, we could log 12 kts.
surfing down waves, but we couldn't average 11 kts. Let me clarify that. In
our first 24 hour run, we may have had periods where we logged 11 kts.over
several hours but at the end of the 1st day we hadn't averaged 11 kts., it
was more like just north of 9, WITH a push from the stream. For comparison
purposes, if we were racing a CR38 in a 140 nm. race like the Trans-Erie we
would owe them over 4 3/4 HOURS at the finish line. The best unaided average
we made was 8.5 kts over 2 hours, absolutely optimal conditions, relatively
flat seas, 15 kts.on the beam. Like I said, I couldn't consider the CR38 a
fast boat, for it's design, it's average at best, and none of the owners
that answered my post would make that claim either. What they did emphasize
was that there boats were VERY well built, VERY well finished, and VERY well
mannered. And they all indicated that it was a 150 mile-day boat with enough
wind, which is a pretty good standard, by most accounts. But again, by most
accounts also, VERY average for blue-water boats of this size. And lastly,
3.7 knots is a huge difference, the difference between right there and over
the horizon.

John Cairns


"Capt. Mooron" wrote in message
...

"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

"John Cairns" wrote in message
...
| Yeah, I have been on the ocean, sailing up the stream, in a 47 footer with
a
| LWL of over 40', AND a phrf rating of 54, by all accounts a fast
blue-water
| passage maker and we couldn't average 11 kts. Sure, we could log 12 kts.
| surfing down waves, but we couldn't average 11 kts. Let me clarify that.
In
| our first 24 hour run, we may have had periods where we logged 11 kts.over
| several hours but at the end of the 1st day we hadn't averaged 11
ktsSNIP

Yeah John... I never claimed to average that speed over the entire
passage... I claimed sustained for a duration... which was by the clock to
win a bet.

How about reading for comprehension.... look back on the posts.

CM