Gardner,
My decidedly unprofessional recommendation would be to go for as much
sail area as you can, without driving yourself crazy in a design sense,
and then rest assured you'll be fine. Your 38' Contrarry with an SA/D
of 50 should be very good. The rest of this long post is basically to
support that statement.
---
If you were located in Oregon near the gorge in Hood River, with huge
average winds, I'd say that an SA/D of 25 would be fine. Probably
overkill, actually. But you're on the Chesepeake Bay, with noticeably
low average wind speeds in the summertime.
Dealing with those low winds would be my driving design criterion for
three reasons:
1) On a boat with an SA/D of 40 or higher, with a lot of the area up
high, you'll be moving when everyone else is still. That matters --
more days sailing per year, and/or less dependence on the outboard.
2) Or, you'll be moving at six knots when everyone else is at three
knots, quadrupling the area you can visit on a daysail, or doubling the
distance you can go one a one-day leg of a cruise.
3) Moving with wind in your face is ultimately more fun than drifting
with an apparent wind of near zero. A boat with a high SA/D will be
able to tack/shunt downwind at an angle, generating a much larger
apparent wind than if it were on a straight run. You won't have a VMG
much better than a run, but the trip will be a lot more fun.
---
Given the need for speed in low winds, I'd shoot for your SA/D of 50
or higher.
I've got a Stiletto 27 catamaran with an SA/D of 50 with two people
on board and the reacher up (i,j calcs -- which is lower than total
sail area), and while I love the boat, there are four issues with sail
area I'd like to resolve:
a) I'd actually like more sail on the really low wind days. There
are days that I know I could enjoy with more sail area, but can't since
I don't have it (or more realistically, don't want to deal with three
sails at the same time while singlehanding)
b) Ideally, that sail area to be higher up. It would be wonderful to
have another two or three meters of mast up high to catch that
delicious elusive breeze. Some people with Stiletto's have done that,
but I don't want to spend a lot of time or money modifying a
lightweight unstable catamaran that has no accommodations.
c) Dealing with high winds can be threatening while singlehanding.
Once reefed, everything is fine, but the issue is going from low winds
to high and then trying to reef such a light boat alone.
d) Too many strings to pull. If I've got the reacher up, I've got to
partially furl it to get it across the forestay. That's a lot of work
if you're not racing, especially if the wind is really, really light,
and you've got the jib up too (which has to be tacked separately).
This also adds to the lack of safety when alone.
So a boat with an SA/D of 50, or even 70, with much of that sail area
high up, and which can be easily reefed, would be ideal for me.
My guess is that this would be useful for you, too. Maybe you'll
sail with one reef in at eight knots, and two reefs at sixteen. But
who cares? As long as your sail is designed properly, there's no
reason *not* to have enough sail area to require one or two reefs in
normal wind.
Rare Bird is a good example. It's an impressive design for a
cruiser, and watching it match the wind speed in the videos is great.
But it's not quite powerful enough for light wind races when other
multi's are using their spinnakers.
You could get an outleader kite for ultra low winds, or rig up a
spinnaker, and get some of the same as the taller mast, but they
wouldn't give you the ability to instantly depower fully while sailing
alone, or alternately, sailing with people who can't scamper all over
the boat to deal with sails while you helm. The spinnaker would also
have a lot of its sail area down low, out of the best winds on light
wind days.
There's no substitute for having sail area up high that you can
depower by releasing a single sheet.
---
So if it were me, i'd go for the largest sail area and tallest mast
possible, regardless of whether the SA/D is 50, 60, or 80, as long as
it fits within three limits:
i) The mast(s) fit under the bridges on the ICW.
ii) The mast(s) are within your acceptable criteria for windage under
bare poles.
iii) The mast(s) work with your travel plans.
I personally don't think I'd bother with item iii because I wouldn't
intend to ship the boat overseas very often, if at all. But I do
understand that you might insist on a container-able design.
The ICW would then be my primary limit, keeping the mast top to 62 or
64 feet. While I've read that there's one bridge as low as 56 feet, I
don't think I'd use that as my limit, and would instead just wait
around for weather good enough to travel outside the ditch for that
segment. One fellow says he's made it with an air draft of 65 feet:
http://icwcruisersg
So I'd probably just go for the largest harryrpoa with an SA/D around
70 and an air draft of 62 to 64 feet.
It would be serious overkill on days when my monohull friends are
hitting their hull speed, but I'll deal with that by reefing, as well
as enjoying the mast's ability to flex and avoid a certain amount of
gust energy.
But on those days when everyone else is bobbing like corks, the
breeze in my face would be exquisite.
---
If you've got a 38' containerable design with an SA/D of 50, I'd say
you'd be set. Not overreaching at all, and definitely far from
underpowered.
I'm all for max sail area, but realistically your design would still
be a monster. It would have the same SA/D of my stiletto, but would
have a lot more of that area higher up, with a 12' longer waterline,
much better stability due to the weight-to-windward hull, and
*infinitely* easier sail handling.
The camper design with an SA/D of 40 would also be good, though not
quite as good in light air. It should still outclass the Elan by a
good amount, though, given the higher SA/D, better stability, and much
longer waterline. If the Elan was good enough for you, the camper
would be even better.
- Mike
On 5/25/2010 10:33 PM, Gardner Pomper wrote: