Sail balance in strong winds

Moderator: GreenLake

Sail balance in strong winds

Postby talbot » Fri May 30, 2014 1:49 am

After lecturing people on this forum on how to manage the jib in strong winds, I went out today almost put the boat over because I didn't follow my own advice. One more time:

With sails trimmed in strong winds, when the boat takes a knockdown strong enough to lose control (rudder and centerboard too far out of the water to steer the boat):
* Both sails have to be slacked.
* Slacking the main alone will not stop the boat, it will allow the jib to turn the boat downwind.
* Once the boom hits the water, the jib has enough power to take the boat the rest of the way over.

The rule of thumb I ignored was keeping the jib sheet in my hand whenever the boat heels continuously over 15 degrees. Today I was handling the main alone, and when the gust hit, the jib just fell away. Once the control surfaces were out of the water, the boat couldn't round up on its own. I released the main, but it could not swing out any farther than where the boom hit the water. I was climbing over the high side as the still-trimmed jib took us down. I don't know why the boat didn't capsize; I think the gust just ended. The leeward coaming miraculously resurfaced and all I suffered was a few gallons of water in the cockpit.

By the way, conditions were breezy but hardly extreme. I measured the wind at 12-16 knots, and I would guess my knockdown gust was maybe 18 knots. Furthermore, the boat was rigged very conservatively. I had double-reefed the main, released the traveler, and tensioned the vang. I had done everything I could except sail the boat properly. Or douse the jib altogether, which I did until the adrenaline had metabolized out of my bloodstream.
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Re: Sail balance in strong winds

Postby GreenLake » Fri May 30, 2014 4:22 am

When you measured the wind, was it while sailing, or before going out?
(Close hauled at around 4.5knts 16.5 kt would be between 13 and 14 in true wind depending on the angle.)

I've had "broaches" where I didn't release the main and had the boat do a kind of pirouette where it would heel to the rail but twist upwind and then right itself. Those may have been associated with sudden strong gusts as well as possible strong wind shifts, because going into these situations we weren't heeled very far.

I just ordered a pair of ratchet blocks for my jib tracks so I can hold the jib more easily in squirrel y conditions. Two days ago I was out in 16+ knots of apparent wind (I measured what I thought was one of the stronger gusts), with no reefs but not alone. We came close to getting the foils out of the water, and also found out later that the rudder had come up 45 degrees (that generates really prodigious weather helm, but my buddy claimed he couldn't see that it was off vertical when he checked it in the water). Anyway, I didn't just keep the tail of the sheet in hand but decided to hold it; just wasn't comfortable with cleating it.

Because of the rudder problem, the boat felt overpowered, but probably wasn't, too bad, really because we were chasing some of the other dinghies that usually get away in lighter winds.
~ green ~ lake ~ ~
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Re: Sail balance in strong winds

Postby K.C. Walker » Fri May 30, 2014 1:54 pm

Talbot,

A few gallons is not bad! I screwed up last summer by not holding on to the jib sheets through the ratchet blocks and I filled up the whole boat. Of course, the jib was my 120 ft.² UPS sail. :-)

When I sail single-handed I definitely feel like the one armed paper hanger. I do have ratchet blocks for my normal jib also but I often cleat and put the line in my lap and just hold the main through the ratchet block. If I do have crew, having ratchet blocks on the jib really makes it possible for them to keep them in hand un-cleated (definitely a good thing). The thing is, I keep my vang line in my lap as well. If the vang is set when the boom hits the water the main can't release any power because the boom is held down (as well as in by the water), so that's another thing to try to remember as you're going over. :-)

I try to keep the boat less than 15°. Actually, I try to keep it as flat as possible, easing and tensioning the sheets continuously. This gives me 15 more degrees of time to release power, if need be. I also give up on close hauled when I get to the point where I can't hold it flat and sail a lower faster groove. I may give up some on VMG but it's probably not that bad, especially if not racing.
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Re: Sail balance in strong winds

Postby talbot » Fri May 30, 2014 2:38 pm

Greenlake: I measured 12kt basic wind speed several times between tacks. The 16kt was measured while underway, so probably it was too high. (My hull speed was >5kt). I have ratchet blocks on jib and main. There was no equipment problem, just pilot error.

KC: I hadn't thought of the vang. Good point. There's no way I could have released it, because it is an old thing that works by jamming the line in a V formed by the sheet-metal sheaves of the lower block. You have to pull the line out then carefully guide it through the system to keep in from rejamming. One more thing to add to my list of jam cleats that should be replaced with cams (at $25 a shot). I think West Marine, Defender, Jamestown, and Annapolis Performance Sailing should subsidize this forum. Every time I log on, someone comes up with something else for me to buy.

And while we're on that subject, what do people know about sail slugs vs. bolt ropes in terms of dousing the main in an emergency? I was impressed with the sail handling on John Albrecht's (jeadstx) boat last year. His slug-equipped main dropped itself smoothly onto the boom in neat folds. But then a local very experienced sailor said that his experience was that slugs were actually more likely to hang up in the track in a douse. Any thoughts? Small Boat Advisor has an article in the current issue about retrofitting a bolt-rope sail with slugs.
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Re: Sail balance in strong winds

Postby GreenLake » Fri May 30, 2014 3:19 pm

I've never had problems with dousing the main. W/o slugs, admittedly it falls into the boat and would have to be kept out of the wind.

I've had one occasion where an emergency drop of the main was needed (not in high winds). That's when I injured myself single-handing. Whatever the system, I would have likely ended up with bloodstains on the sail and halyard like I did in that case (unavoidable when bleeding profusely from your dominant hand...).

We reached the high 5 kts at times, not sure we had when I measured. Looks like we had comparable conditions then; with two people we were able to carry full sail despite messing up the rudder. Leaving the jib uncleated probably contributed, because when my helmsnan, who is used to small keelboats, was too nonchalant about heeling the boat I'd ease up on the jib. :o
~ green ~ lake ~ ~
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Re: Sail balance in strong winds

Postby K.C. Walker » Fri May 30, 2014 9:40 pm

I've had no problem with sail slugs sliding easily, actually that's not altogether true. With sail slugs they will drop out of the feed slot if you don't put a stopper or a mast gate in. If you have a stopper, which is the easy solution, then it's difficult to reef the mainsail. I put in a bungee loaded mast gate and it's not 100% reliable but works pretty nicely to hold the slugs in the slot.

Yeah, I had one of those vang setups. I was happy to move on.
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Re: Sail balance in strong winds

Postby TIM WEBB » Sat May 31, 2014 4:05 pm

I've found the sail slugs to be invaluable for single-handing. A little Elmer's Slide-All sprayed into the track once in a while keeps 'em smooth. Started out using a sail track stop, but after fumble-fingering a couple of those overboard, went with a bungy-hinge mast gate:

http://www.mastgates.com
Tim Webb
1979 DS2 10099 The Red Witch
(I used to be Her "staff", in the way dogs have owners and cats have staff, but alas no longer ... <pout>)
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