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Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

Pulpit and Jib shape?

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Justincase
1st Mate

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Canada
49 Posts

Initially Posted - 01/28/2011 : 10:34:58

Looking at a few pic's of last summers season last night and one thing caught my eye. In almost all of my pictures the pulpit is causing the bottom of the jib/genoa to ride up it. Is this hurting my sail shape? In the summer we tend to get light winds. I was thinking of adding a short bight of line that would rase the sail up from the forstay attachment by about a foot or so. So the sail would not interfere with the pulpit as much. Am I making somthing out of nothing? But there seems to be a lot of discussion about sail shape and its importance

Justincase

Justincase
"Kiliki" 1981 SK/SR
#2724
Calgary Canada

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DaveR
Master Marine Consultant

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USA
2015 Posts

Response Posted - 01/28/2011 : 10:44:45

That's what I do Justin, also allows you to see under the sail a little easier.

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dmpilc
Master Marine Consultant

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USA
4593 Posts

Response Posted - 01/28/2011 : 13:58:13

I do that, too, had a wire pigtail made, about 12-15" long, when we changed from wire/rope to all rope halyards. You might be able to see the effect in my signature photo. The sail is a 150 drifter. I also use a pigtail on our working jib. Both stay attached to the sails. It won't work on our full-hoist 135 and regular 150.
I suppose using 5/16" rope would work also.

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pastmember
Master Marine Consultant

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2402 Posts

Response Posted - 01/28/2011 : 16:37:28

Especially in light air, the wind is better off the deck. Does your lifeline run parallel to the deck or does it fasten to the bottom of the pulpit?

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Justincase
1st Mate

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Canada
49 Posts

Response Posted - 01/28/2011 : 20:13:19

Frank, that's exactly what I'm talking about... My lifelines attach at the bottom of the pulpit just like yours.

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Voyager
Master Marine Consultant

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USA
5373 Posts

Response Posted - 01/29/2011 : 15:50:36

I've added a piece of doubled line to raise my genoa up by about 16". There's a short piece of wire attached to the head that I simply tie off, I've never used it. The foot still rests slightly on the bow pulpit and forward end of the lifelines when in use, but not to such a great extent to adversely affect the sail shape. I've adjusted the length of the line to allow the luff to fit all the way up into the furler track without binding it.

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Stinkpotter
Master Marine Consultant

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Djibouti
9080 Posts

Response Posted - 01/29/2011 : 21:52:56

You'll see this on some of the biggest, hottest racers... Sheeting angles are different, but when they're not on a hard beat, they'll often have the jib foot hanging over the pulpit. Off the wind a little, they want some fullness anyway, so the pulpit doesn't adversely affect the shape. Note the 100' $multi-million maxi here at the start of this year's Sydney Hobart Race...

Hard on the wind, you should be able to trim so the jib is laying on the inside of the pulpit and the foot is over the low part of the lifeline. If not, try moving your cars back on the track, which will flatten the lower part of the sail. (That's the prescription for stronger winds.)

When you raise the whole genny--especially a 135-155--you're raising the center of effort (CE) of the rig by a significant amount. Higher winds will produce more heeling force, but the improvement in overall shape will be very small. One of the good things about the headsail is that it generates much more power down lower than the main (therefore with less heel). The less heel, the more efficient both sails are overall. I'd leave it down there. (...and I did.)

Edited by - Stinkpotter on 01/29/2011 21:58:24

Steve Milby
Past Commodore

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USA
5902 Posts

Response Posted - 01/30/2011 : 06:23:31

The short, direct answer to your question, Justin, is I think you're making too much of it. This is an interesting question, because, as an active racer, I know that eliminating even small wrinkles in sails can make a significant difference in the sail's efficiency. Generally, every little wrinkle in a sail creates turbulence, and causes the laminar flow of wind to separate from the surface of the sail. When that happens, that part of the sail stops generating power, the boat loses a little speed, and it punches through the waves a little less vigorously. All that having been said, however, I don't believe there's any good reason to worry about the little piece of sail that occasionally drapes cver the pulpit. First, more often than not, headsails made for our boats are decksweepers, or nearly so. Sails with a quickly rising foot are used more for offshore sailing, because big waves can break over the bow, and rip the foot of the sail. That is rarely a problem where our boats usually sail, so most decksweeping genoas are designed so that they will drape over the pulpit slightly. What that means is that everyone's sail does the same thing. As a result, even though you undoubtedly lose a slight amount of power due to that imperfection, it will affect everyone to about the same extent, so, the "playing field" is still level.

The overall basis on which a sailboat operates is to balance the amount of lateral resistance created by the keel, against the amount of force generated above the waterline, by the sails. When you raise the sail's center of effort, you are lengthening the lever arm above the waterline. As the winds increase, the boat will begin to heel a little earlier than other boats, and you'll have to tuck in a reef a little earlier. For maximum efficiency, the tack of the jib should be as low as possible. If you're a racer, that's the way you'll want to rig your genoa. However, if you're a cruiser, raising the foot of the jib certainly improves your field of vision foreward, and, unless you're sailing side-by-side with other boats, the difference really won't be noticeable. It's your boat. Rig it any way that you like, as long as it's fundamentally safe.

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Justincase
1st Mate

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Canada
49 Posts

Response Posted - 01/31/2011 : 10:47:45

Thanks for the well thought out answers, thats why I love this forum! I'm not a racer so performace is not as imprtant to us as safety and comfort. I like the idea of having a better view forward how ever the admiral might not like the extra heeling. I'll try it both ways to get a feel for the diffrence. I'll be sure to report my findings back. But that won't be for a bit just got another foot of snow and now it's -28*C. Thanks for all of the great input.

JC

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