boomless main
MCsenger
designed for the Farrier F-25 trimaran. According to the folks
involved, the boat sails better and wins races with the new rig.
Seems that off the wind you'd sacrifice a lot of sail shape, but the
article didn't mention anything about it. Any thoughts here?
I might like to try the idea on a dinghy I'll build this winter.
Figure I'd need a short boomkin off the transom to get the clew back
far enough. Or to keep things simple I could build a free-standing
cat rig. The boomless idea simply appeals to my dented skull.
-Michael Csenger
Martin Schoon AR/RH
>I came across a Multihulls Magazine article describing a boomless main
>designed for the Farrier F-25 trimaran. According to the folks
>involved, the boat sails better and wins races with the new rig.
>
>Seems that off the wind you'd sacrifice a lot of sail shape, but the
>article didn't mention anything about it. Any thoughts here?
>
boom doesn't help off the wind shape much.
Many beach-cats and some bigger cats have boom-less mains.
============================================================================
Martin Schoon <era...@eras70.ericsson.se>
"Problems worthy of attack
prove their worth by hitting back"
Piet Hein
============================================================================
George Loney
There's not as much need for a boom on a cat because you've got the
space for a big long traveller, you can attach the main sheet to the
clew of the sail, and we don't do that much straight downwind work
anyway.
Dave Mills
Wharram cats have been using a boomless main for quite a while now. I
realise we are comparing chalk and cheese (Wharrams to an F-25) but I'm a
big fan of the concept for cruising. With the Wharram, you actually get
very good control of sail shape, because twist is totally controllable
with the vangs to the (short) gaff. Somehow I can't picture and F-25 with
a gaff !!. It's hard to say what the effect will be downwind without
seeing the set-up. The Wharrams have a traveller that runs the full width
between the two hulls - this may be a bit hard to achieve on your dingy.
The amount of 'balloon' you can pull out of the sail will obviously
depend on the ratio of the length of the foot of the sail to the width of
the mainsheet traveller.
mct...@dct.ac.uk
standing lugsail. The sheet went around a thumbcleat on the lee quarter and
was shifted across each time I went about. This is pretty well essential
to stop the clew curling in towards the centreline.
The reason I gave it up and put on a boom was that multipart central sheeting
was easier - it needs a lot of pull on the sheet to flatten a boomless sail
for good windward performance. It may be no big deal with a winch, but it's
tough on the arms without one!
Bill Samson
In article <42i95k$e...@usenet4.interramp.com>, ir00...@interramp.com (MCsenger) writes:
> I came across a Multihulls Magazine article describing a boomless main
> designed for the Farrier F-25 trimaran. According to the folks
> involved, the boat sails better and wins races with the new rig.
>
> Seems that off the wind you'd sacrifice a lot of sail shape, but the
> article didn't mention anything about it. Any thoughts here?
>
Donald Wigston
> I came across a Multihulls Magazine article describing a boomless main
> designed for the Farrier F-25 trimaran. According to the folks
> involved, the boat sails better and wins races with the new rig.
>
> Seems that off the wind you'd sacrifice a lot of sail shape, but the
> article didn't mention anything about it. Any thoughts here?
>
> I might like to try the idea on a dinghy I'll build this winter.
> Figure I'd need a short boomkin off the transom to get the clew back
> far enough. Or to keep things simple I could build a free-standing
> cat rig. The boomless idea simply appeals to my dented skull.
>
> -Michael Csenger
I think that one of the reasons that the boomless main works so well on
the F-25C is that the mainsail never has to be let out very far, because
the boat should never really be sailed deeper than about 90 degrees to the
apparent wind. And in any case, having no boom allows even more control of
the depth of the sail, in that you can make the mainsail much more full
than if it is on a boom.
I have been on an F25C, and I like the boomless rig. It allows the sail to
be lower, since if it grazes your head on the way over it does little more
than knock off your cap or ruffle your hair. The main disavantage that I
see is that there is there is nowhere to store the sail when not in use.
You can use lazy jacks, but they are a bit untidy.
On the other hand, the F-31 boomless rig on Caliente III is a real
handful. Since the mainsheet is also acting as the outhaul, the loads on
the mainsheet of the F-31 (with taller 42.5 ft mast) are very high, even
with a high an low ratio sheeting set-up. So I think it works well on
smaller boats like the F-25C, but not so well on bigger boats.
--
Donald Wigston
Atlanta, GA
Larry Suter
writes:
>I came across a Multihulls Magazine article describing a boomless main
>designed for the Farrier F-25 trimaran. According to the folks
>involved, the boat sails better and wins races with the new rig.
>
>Seems that off the wind you'd sacrifice a lot of sail shape, but the
>article didn't mention anything about it. Any thoughts here?
It may be that the F-25 is fast enough that the apparent wind is always
fairly forward of the mast. If you we're sailing directly downwind, the
sail shape would likely be awful. But if you came to weather a bit,
even with the true wind mostly behind you, the boat speed would move
the apparent wind much further forward than in a slower boat.
>I might like to try the idea on a dinghy I'll build this winter.
A dinghy may not be that fast so the apparent wind won't move as far
forward. So on runs you'll need a sail set for runs.
> The boomless idea simply appeals to my dented skull.
>
Now that makes sense, and is all the reason you need to do it. Besides,
you'll be able to launch it earlier if you don't need to build a boom.
BTW, blue polytarp sails with duct-tape reinforcement for luff, leech,
foot, head, clew, etc. are a quick and cheap way to make a sail for
your experiment. If you want to get fancy and put some curvature in by
broadseaming, you can do that as well.
Have fun,
Larry Suter
Dogstar (Triton) SF Bay
Daisey (Block Island Boat) Trailer
Doghouse (Inverted Skiff) Backyard
>
Larry Appelbaum
: I came across a Multihulls Magazine article describing a boomless main
: designed for the Farrier F-25 trimaran. According to the folks
: involved, the boat sails better and wins races with the new rig.
: Seems that off the wind you'd sacrifice a lot of sail shape, but the
: article didn't mention anything about it. Any thoughts here?
: I might like to try the idea on a dinghy I'll build this winter.
: Figure I'd need a short boomkin off the transom to get the clew back
: far enough. Or to keep things simple I could build a free-standing
: cat rig. The boomless idea simply appeals to my dented skull.
: -Michael Csenger
I built and sailed a Bolger/Payson Cartopper with a loose-footed
sprit-main. It worked well, and didn't bang your head when tacking. It
was sheeted like a genoa, to a fairlead on the leeward gunwale. For long
downwind runs, I tried to hold the clew out with an oar.
Even though the sail was cut flat, its shape when sailing was very full.
Also, it was difficult to reef. For me, it made a good dingy/daysailor,
but it was limited in strong or gusty winds by the inability to depower
the sail.
Larry Appelbaum, St. Louis, Missouri (l...@mo.net)
vande...@sgcl1.unisg.ch
> On the other hand, the F-31 boomless rig on Caliente III is a real
> handful. Since the mainsheet is also acting as the outhaul, the loads on
> the mainsheet of the F-31 (with taller 42.5 ft mast) are very high, even
> with a high an low ratio sheeting set-up. So I think it works well on
> smaller boats like the F-25C, but not so well on bigger boats.
From my own experience, I'd disagree. We sail a boomless RC-27 with
a 44.4 ft mast and a mainsail of 366 sq ft. Sheeting is done via
a 16 part purchase with the sheet exiting through two cam cleats,
allowing us to also use the sheet as a 8 part purchase. The system
works perfectly, I can work the sheet from my helmsman position on
the trapeze.
Granted, the boomless setup works only because the boat is usually
sailed close hauled (high speed deflecting the apparent wind). It's
probably best for fast multihulls with wide travellers.
Claas van der Linde
RC-27 Oiseau Roc
vande...@sgcl1.unisg.ch
...make that high speed deflecting the true wind...
Martin Schoon AR/RH
>
>I think that one of the reasons that the boomless main works so well on
>the F-25C is that the mainsail never has to be let out very far, because
>the boat should never really be sailed deeper than about 90 degrees to the
>apparent wind. And in any case, having no boom allows even more control of
>the depth of the sail, in that you can make the mainsail much more full
>than if it is on a boom.
How? Or should I ask why?
>
>On the other hand, the F-31 boomless rig on Caliente III is a real
>handful. Since the mainsheet is also acting as the outhaul, the loads on
>the mainsheet of the F-31 (with taller 42.5 ft mast) are very high, even
>with a high an low ratio sheeting set-up. So I think it works well on
>smaller boats like the F-25C, but not so well on bigger boats.
>
I know of at least two F-40:s with boom-less mains.
One disadvantage I can come up with is that it limits your freedom of
for/aft-placement of the rig. Virtually all F-28:s and my boat have the
main right up to the transom.
KWilson800
>I came across a Multihulls Magazine article describing a boomless main
idea on >a dinghy I'll build this winter. . . The boomless idea simply
appeals to >my dented skull.
I can't say anything intelligent about the boomless sail on the trimaran,
but I have some thoughts about using it on a dinghy:
- Sheet forces will be significantly higher. With a conventional boom
along the foot of the sail, the mainsheet keeps the boom down (assuming no
vang) and toward the center of the boat. The boom keeps the clew of the
sail from moving in toward the mast. Without the boom, the sheet will
have to do this. I've sailed in many small boats with boomless
spritsails, and generally the sheet forces are fairly brutal (for the size
of the sail) in any breeze at all. You could, of course, put a block at
the clew like Drascombes do, but this defeats the idea of not bonking
yourself on the head, since a block flailing around when the sail is
luffing is worse than any boom.
- There is some possibility of quite unpleasant rythmic rolling while
running downwind. I don't know why this happens (maybe someone reading
this could enlighten us), but I think the distorted shape of the sail
going downwind has someting to do with it. The problem is usually much
worse with a boomless main.
Why not use a sprit boom rig a la Bolger?
Several advantages:
- The boom is up out of the way of your head
- Low cost, no fittings to buy.
- The sail is self-vanging.
- Lowest possible sheet forces, since the sheet does not have to hold the
boom down. 80 sq ft is easily controlled with a 1-part sheet.
- You have a line on the boat called a snotter, which starts a lot of
conversations.
- Excellent control of sail shape with snotter tension.
- Little or no chance of downwind rythmic rolling. I've never experienced
it in a boat with a sprit boom unless the sail goes forward of the mast.
- You can get a nice 60 sq ft Bohndell sail from Dynamite Payson for
about $200.
Reefing is difficult, true, and
luff tension is critical. The boom cuts into the sail on one tack, which
theoretically makes it less efficient, but I've never been able to notice
the difference. Have fun!
Keith Wilson
Neil Hoyles
writes:
>Michael Csenger writes:
>>I came across a Multihulls Magazine article describing a boomless
main
>>designed for the Farrier F-25 trimaran . . . I might like to try the
>idea on >a dinghy I'll build this winter. . . The boomless idea
simply
>appeals to >my dented skull.
>
because the sheeting base is wide enough to give good sail trim even
without a boom. In a monohull of modererate beam the sheeting angle is
only good for close-hauled sailing. Off the wind, you cannot get the
clew and leech of the sail far enough outboard to avoid strong weather
helm developing; The center of effort of the sail is too far aft. The
problem can be overcome with a whisker-pole type spar to pole the sail
out, but then why not fit a proper boom in the first place?
In boats designed to be rowed as well as sailed, the disadvantages of
the boomless main sail are often accepted to obtain the greater good of
noggin safety for the rowers. The sailing qualities off the wind do
suffer though. We used to pole the clew out with an oar. Lost a few
oars that way...
--
Neil Hoyles
neil...@ix.netcom.com