Spinnaker sheeting

[bruceb]

I am setting up an old tri for more modern a-sails. Is there an optimum sheeting angle as a starting point? I realize I can barber haul in or out, but what are spinnakers designed for in optimum VMG conditions? Also for code 0s? Any thoughts would be appreciated before I start drilling holes The boat is plenty wide so almost any location/angle is possible.
B

 

[Doug Lord]

Bruce, if you don't have a sailmaker near you you could ask mine: Scott Morgan, Sails by Morgan,Cocoa ,Florida 321-633-7245. He's a good guy and I'm sure he'll help.

 

[CT249]

It depends....

Formula 40 racing in a close fleet in flat water? Piver Lodestar doing beercan racing?

I'm no expert, but the contrast in spi angles and depths between fairly fast multis and even something moderate like a late '80s/early '90s racer/cruiser tri seems to be so vast that you may really have to talk to someone with significant specialist experience. The range of possibilities appears to be absolutely enormous; even the issue of exactly how far you are prepared to go to heat the boat up in breezy conditions seems to have a major impact.

One other issue is whether A sails are faster at all, on average, in your area. In reality in many conditions a lot of older tris are not normally faster downwind than a lot of modern monos that actually go faster under symmetrical sails. I know an ex Skiff sailor/champion who reckons that his medium-pace multi is normally quicker running deep under symmetrical kite instead of tacking downwind at high angles under an assy.

 

[bruceb]

Old sailors and their old boats

CT, I have been club racing a Buc 24, and I am now moving up to a Buc 33. A light foam core 33, but definitely old school. I don't expect I will be foiling
I have been using a-sails on my 24 and racing with the local fairly competitive sport boat fleet with similar sails, with good results. I have noticed that as the wind increases, I reach a point that I am faster sailing almost dead down wind, even with my a-chute.
My # 1 spinnaker on my 24 was built for a melges 24 and seems to like being sheeted and sailed pretty tight. Since they are narrow, they don't have much choice but the 33 has lots of open space and I wondered if a spinnaker designed for it would sheet farther outboard. I am mostly trying to anticipate where I need to mount some turning blocks before I re-assemble the boat. (soon )
I don't have anything local to compare too. We don't have many fast tris around.
B

 

[Erwan]

A beach cat designer and Tornado medalist in 92, took me on his F18 almost 20 years ago.
I was the crew, but with only A-Cat experience.
He sum up the good spinnaker trimming in a short and synthetic sentence:

The leading edge of the spinnaker must be a the limit of experiencing "Vibrations" .
If it starts to "Vibrate" you sheet in a little bit .

 

[bruceb]

Vmg ?

Jib sheeting angles have gone from "where ever the track will fit on the deck" to a fairly tight range for optimum flat water- point high settings. You can still trim a jib to a 12 degree sheeting angle and the tel-tales will agree that you are trimmed in "all the way", but for most faster boats, you would be giving up a lot of distance for a little gain in speed.
My question still is "is there an optimum sheeting angle for a modern a-spinnaker?" for a medium performance boat.
B

 

[CT249]

Still seems to me that there is such a wide variety of possible ways to attack the question that you'd be better off talking to someone who specialises in multi sails. Perhaps you could work out how the Bruce Number compares to a Farrier of vaguely similar size and find out their sheeting angle?

A Bucc 33 would be slower than the 31'er I was sailing on, and we were regularly pulling the tack to windward of the main hull bow and sailing low angles. The boat averages about 4th in division in the nationals so it's not too slow.

 

[bruceb]

More details?

CT, I suspect you are correct on all counts, but I wanted to do a little research (and sail my boat a little) before I started in on sail makers. We only have a very few sail makers with any actual "mid" multi experience. A couple of lofts dominate a very small market here in the southeastern US.
Other B-33's seem to sail about the same as a C-27/28, mine might be a little lighter than most, which never hurts. The 33 caries a larger masthead spinnaker than the C-31's, the Bruce numbers are about the same.
How, and how much do you move the spin pole to weather on the 31?
B

 

[CT249]

From memory, about 3' to leeward of the windward float at the most. This was in an offshore series where it was normally either blowing dogs off chains or very light reaching, so I'm not sure what the full range was.

We didn't have a pole to move it to weather. The tack came off the bowsprit and onto a line running to the weather float bow.

The boat rated midway between an F82R and an F27; it was over-built and I think it was rated for carrying full offshore equipment.

Those Buccs sound like they are doing pretty well! I seem to recall Lock saying that they were built for offshore stuff so not as quick, for length, as the 24, but for an old boat hanging in with 27s and 28s seems to be pretty damn good.

 

[bruceb]

go deep

Thanks CT, that is interesting, and pretty easy (and quick) to set up. I will try it.
The 33 does have a fairly low aspect rig compared to most modern designs, at least I have tried to get all the weight out of it I can. Most of the wooden 33's are heavier than mine. The photos (from a previous owner) are the sails that it came with, and I expect to replace once I get a feel for it. I have eliminated the backstay so I can use a larger full batten main. Without changing the mast, I am stuck with the spinnaker size, I expect the jibs are ok as is.
My over-rigged B-24 is probably faster in light air, I will just have to get used to that.
B