the problem with extending this reasoning to a long voyage is that fuel
capacity limits how far you can motor. to the extent that the PHRF
difference reflects differing light air performance, the extra time could be
a lot more.

on a short voyage, you turn on the motor when boatspeed goes below your
chosen figure. on a long passage, you might find yourself sailing in awind
that you otherwise might motor in.

jeff

Paul L wrote:

"DSK" wrote in message
. ..

Wayne.B wrote:

The difference between PHRF 140 and 180 is less than half a knot.
That's a huge difference to a racing sailor but I wouldn't worry too
much about it for cruising.

Agreed, but it should also be noted that the difference in windward
performance could be bigger than the PHRF rating difference.

BTW one way to figure the difference in boats by their PHRF ratings is
that each point lower equals approx one second per mile. So a difference
of 40 means about half an hour over 45 miles. Is that significant?
Prob'ly not to most cruisers.

Or about one full day on a 2,000 mile transpacific hop.

Paul
www.jcruiser.org

On Wed, 05 May 2004 16:26:56 GMT, jeff feehan
wrote:
the problem with extending this reasoning to a long voyage is that fuel
capacity limits how far you can motor. to the extent that the PHRF
difference reflects differing light air performance, the extra time could be
a lot more.
======================================

Even starting off with a boat that has decent light air performance,
once you load it down with cruising gear, fuel and water, performance
goes out the window in most cases. Add in a 3 blade fixed prop, a
slightly dirty bottom and heavily built cruising sails, and you might
as well figure on motor sailing in anything under 12 kts or so. It's
important to note that motorsailing is usually done at low engine revs
and is fairly fuel efficient. If you're range limited however you
don't have much choice except waiting fot the wind to cooperate.

"Wayne.B" wrote in message
...
On Wed, 05 May 2004 16:26:56 GMT, jeff feehan
wrote:
the problem with extending this reasoning to a long voyage is that fuel
capacity limits how far you can motor. to the extent that the PHRF
difference reflects differing light air performance, the extra time could
be
a lot more.
======================================

Even starting off with a boat that has decent light air performance,
once you load it down with cruising gear, fuel and water, performance
goes out the window in most cases. Add in a 3 blade fixed prop, a
slightly dirty bottom and heavily built cruising sails, and you might
as well figure on motor sailing in anything under 12 kts or so. It's
important to note that motorsailing is usually done at low engine revs
and is fairly fuel efficient. If you're range limited however you
don't have much choice except waiting fot the wind to cooperate.

One of the dirty little secrets of long-distance cruising, among others, is
that they spend more time under power than you might think. Of course, some
of it is just taking advantage of the time spent recharging batteries, might
as well get some extra speed out of that time.
John Cairns

"Wayne.B" wrote in message
...
On Wed, 05 May 2004 16:26:56 GMT, jeff feehan
wrote:

Even starting off with a boat that has decent light air performance,
once you load it down with cruising gear, fuel and water, performance
goes out the window in most cases. Add in a 3 blade fixed prop, a
slightly dirty bottom and heavily built cruising sails, and you might
as well figure on motor sailing in anything under 12 kts or so.

I have a different take on this. I race on a moderately heavy 42'er
(24k lbs ~11k kg). I have been on this boat both when she was
loaded down for a trip around South America and also racing light.
She sails really well in all conditions no matter what her load. I think
the big thing here is that she has plenty of sail area to keep her moving
(SA/D is around 20).

I have also seen boats like an ultralight Olson 40 loaded down with a
couple thousand pounds of crew and they still go upwind and down
like a scalded cat. Of course, in cruising mode they won't go
upwind quite as well unless you want to move the Dinty Moore
to the windward rail at each tack. But downwind and reaching
they'll still be fast. Slower than if she was not burdened with
a bunch of extra weight, but it will still walk away from the
Baba 40, with a lot less effort to boot.

If you take a light boat and don't give her enough sail power, then when
you load her down she may fall into the poor performance range.

Personally, I think one of the reasons people don't sail in the light
stuff is that their boats don't have enough sail area to keep going
without the hassles of a big overlapping genoa. But if you have a
relatively high SA/D ratio, then when you make all the compromises
for your cruising sails (like a high clew and less overlap) you still have
enough power left over to actually make light air sailing rewarding. But I
also think that if you have a decent performing boat then you're more likely
to pay attention to things like dirty bottoms (and take care of that), and
are less likely to put a three blade prop on the boat. The skipper of the
42'er considered a two blade fixed prop for the trip up the coast from
Califonia to Washington because he thought he might need to motor
against the wind a lot. He never did it though, he's too much of a
sailor at heart and kept the old folding prop on. He couldn't stomach
the half knot hit on the sailing performance.

Most long distance cruising boats are poor sailing performers, requiring
lots of wind to make them move. If they were better performers then they
would probably be sailed a lot more often rather than motored so much.

Paul
www.jcruiser.org
"jeff feehan" wrote in message
ink.net...
the problem with extending this reasoning to a long voyage is that fuel
capacity limits how far you can motor. to the extent that the PHRF
difference reflects differing light air performance, the extra time could
be
a lot more.

on a short voyage, you turn on the motor when boatspeed goes below your
chosen figure. on a long passage, you might find yourself sailing in awind
that you otherwise might motor in.

jeff

Paul L wrote:

"DSK" wrote in message
. ..

Wayne.B wrote:

The difference between PHRF 140 and 180 is less than half a knot.
That's a huge difference to a racing sailor but I wouldn't worry too
much about it for cruising.

Agreed, but it should also be noted that the difference in windward
performance could be bigger than the PHRF rating difference.

BTW one way to figure the difference in boats by their PHRF ratings is
that each point lower equals approx one second per mile. So a difference
of 40 means about half an hour over 45 miles. Is that significant?
Prob'ly not to most cruisers.

Or about one full day on a 2,000 mile transpacific hop.

Paul
www.jcruiser.org