I had my shelf foot main converted to a regular foot because the shelf
wasn't really doing anything and the sailmaker though we could take out a
bit of draft to reduce backwinding. The foot folds were unsightly and the
sail no longer responded to changes in outhaul tension.

I got the draft reduction but now I have a big wrinkle running just ahead of
the battens. The shape was great in that area previously and now it looks
terrible. Since all that was changed was the shape of the foot, it seem I
should be able to fix it by fiddling with the lengths of the seizings that
secure the slides.

I'll be talking to the sailmaker on Monday but I would appreciate any advice
that would help me sound a bit more knowledgeable about the problem.

--
Roger Long

I could only find a few accounts of boaters using these.
Here's two that were somewhat detailed:
http://www.woodenboatvb.com/vbulleti....php?p=1569460
http://www.sailsarana.com/FAQ.htm#why
All swore by them, and one was newly installed, and he was ok
so far, but he didn't follow up.
They note the only drawback is the small size of the urine container.
I suspect they all just dump the urine over the side - one admitted it
- but in any case a container of **** is easier to dump into a shore
toilet than a load of crap.
It's hard to say for sure, but it appeared most of the owners were
cruising couples, or couples with small children. There were notes
about guests aboard, but no mention of parties. I'm assuming the
holding tank/pumpout method is best for those who get heavy traffic in
the head, but may even be wrong about that.
According to these accounts they have no holding tank, no plumbing
issues, no thru-hulls, no stink issues, and gain considerable space.
The only power used is by a 12V fan (50-120mA, depending on which
account) which is supposed to run constantly. One uses a solar
powered vent instead of 12V and says it does the job.
The footprint is small, same as a porta-potti, but the Airhead is
taller.
I suppose there aren't many accounts because it is a relatively new
system (2002?), and they are expensive - @1k.
Not bad when compared to the cost of a new holding tank system,
but most cruisers already have a holding tank system, so the incentive
to spend the 1k to replace instead of smaller sums to keep on fixing
it is negative.
The urine/solid separation technique appears to be gaining favor
in some areas of the world, and makes sense for a few reasons,
biological and mechanical.
I'm planning to buy some kind of cruising boat, and if I can avoid
playing sewer worker as part of the "cruise experience" - good.
I've read too many stories about **** disasters to wish it upon
myself. Spent some time doing sewer tile work in 6' trenches, and
had all I need of playing Ed Norton, even at a pumpout.
Another thing that turns me from the current holding tank method of
waste is just driving over a bridge where there's a crowded marina
below. Smells like crap. Maybe that's just my limited experience
near St Pete Beach, and maybe that's home runoff into Boca Ciega Bay,
but I've read a lot of cruiser stories about filthy harbors.
And bilges.
I'm really interested in hearing a thorough review from anybody who
uses the Airhead, or even second-hand info from those who know people
who have them.
But any comments are welcome. I'm a boat head newbie.

--Vic

Vic Smith wrote:
I could only find a few accounts of boaters using these.
Here's two that were somewhat detailed:
http://www.woodenboatvb.com/vbulleti....php?p=1569460
http://www.sailsarana.com/FAQ.htm#why
All swore by them, and one was newly installed, and he was ok
so far, but he didn't follow up.
They note the only drawback is the small size of the urine container.
I suspect they all just dump the urine over the side - one admitted it
- but in any case a container of **** is easier to dump into a shore
toilet than a load of crap.
It's hard to say for sure, but it appeared most of the owners were
cruising couples, or couples with small children. There were notes
about guests aboard, but no mention of parties. I'm assuming the
holding tank/pumpout method is best for those who get heavy traffic in
the head, but may even be wrong about that.
According to these accounts they have no holding tank, no plumbing
issues, no thru-hulls, no stink issues, and gain considerable space.
The only power used is by a 12V fan (50-120mA, depending on which
account) which is supposed to run constantly. One uses a solar
powered vent instead of 12V and says it does the job.
The footprint is small, same as a porta-potti, but the Airhead is
taller.
I suppose there aren't many accounts because it is a relatively new
system (2002?), and they are expensive - @1k.
Not bad when compared to the cost of a new holding tank system,
but most cruisers already have a holding tank system, so the incentive
to spend the 1k to replace instead of smaller sums to keep on fixing
it is negative.
The urine/solid separation technique appears to be gaining favor
in some areas of the world, and makes sense for a few reasons,
biological and mechanical.
I'm planning to buy some kind of cruising boat, and if I can avoid
playing sewer worker as part of the "cruise experience" - good.
I've read too many stories about **** disasters to wish it upon
myself. Spent some time doing sewer tile work in 6' trenches, and
had all I need of playing Ed Norton, even at a pumpout.
Another thing that turns me from the current holding tank method of
waste is just driving over a bridge where there's a crowded marina
below. Smells like crap. Maybe that's just my limited experience
near St Pete Beach, and maybe that's home runoff into Boca Ciega Bay,
but I've read a lot of cruiser stories about filthy harbors.
And bilges.
I'm really interested in hearing a thorough review from anybody who
uses the Airhead, or even second-hand info from those who know people
who have them.
But any comments are welcome. I'm a boat head newbie.

--Vic

I would not recommend Vic's solution to your mainsail problem. Marine
toilets and holding tanks look stupid when sewn to the foot of a mainsail,
and will only add to you creasing problem.

You say "all that was changed was the shape of the foot", but it seems to me
that is exactly where the problem lies. The shelf is there to provide shape
and to give extra area when running downwind, always assuming you have
adjustment at the outhaul, and use it.

The shape of the individual panels has to be repeated in the foot, otherwise
you are creating all manner of vertical stresses in the mainsail, to flatten
a well-cut main, you tighten the luff and the foot, and the shelf should
then fall neatly into a pleat. Some mains have a zipped shelf to neaten the
appearance and create this flatter shape.

This obsession with backwinding (usually from an overtightened genoa or
leech line) is a problem many sailors seems to have an obsession about,
thinking that it is slowing the boat, which it isn't. Learn to live with it,
and DO NOT follow Vic's advice re holding tanks. Your main will look awful
with one of these incorporated!

DP

What we were trying to do was replicate the effect of a shelf foot main with
the flattening zipper zipped up (although my sail didn't have one). I'm not
likely to go fiddling with outhauls to just got .05% extra speed downwind
while cruising. I want a set and forget main except for the cunningham and
reefing. A little more halyard tension when setting on brisk days and a
little less on mild ones is about the extent that I want to fool with it.
When you aren't racing, the first 97% of the speed comes free as long as
your basic sail trim is right.

Clearly a mistake was made. I'll get some pictures today and go up and see
the sailmaker tomorrow.

--
Roger Long

If I these wrinkles are running at an approximately the same angle as
the angle from the clew to the head ... they are probably 'girts'
caused by the extreme outhaul tension.

If thats the case adding reinforcement patches to the clew area 'may'
help to spread out the 'forces'. Otherwise, you'll probably have to
lengthen the battens so that the leading edge 'end' is no longer in
the same 'line' that these 'girts' usually form.

When this happens, you might try increasing halyard tension of the
luff .... if your boat has a bit of weather helm pressure.

When you excessively tension o ne side of a sail, you usuallly have to
tension the 'other' side or such 'girts' will appear. So these
wrinkles may be nothing more and a sail with an aggressively stretched
foot and not enough stretch on the luff.

hope this helps.


In article , Roger Long
wrote:

I had my shelf foot main converted to a regular foot because the shelf
wasn't really doing anything and the sailmaker though we could take out a
bit of draft to reduce backwinding. The foot folds were unsightly and the
sail no longer responded to changes in outhaul tension.

I got the draft reduction but now I have a big wrinkle running just ahead of
the battens. The shape was great in that area previously and now it looks
terrible. Since all that was changed was the shape of the foot, it seem I
should be able to fix it by fiddling with the lengths of the seizings that
secure the slides.

I'll be talking to the sailmaker on Monday but I would appreciate any advice
that would help me sound a bit more knowledgeable about the problem.

--
Roger Long