Self-Tacking Rigs

[Ron Hotchin]

There's been some discussion on the self-tacking abilities of sprit rigs, especially with the various B&B designs. Is this an inherent quality of the sprit rig, and if so, why, or is it also because B&B uses separate port and starboard mainsheets to provide the control? I'm working on the running rigging for my Catbird 16, which I've changed from a sprit rig cat ketch to balanced lugsail. Would a balanced lugsail similarly rigged with two mainsheets provide more control than a single mainsheet? Inquiring minds gotta know! Thanks,
Ron

[Gordy]

Ok Ron,

No.

No.

And no.

The B&B cat-ketch is self tending during a tack because there's no jib sheet that has to be let free before the other can be taken up. On the cat-ketch, if your respective sails are set on one tack they will be set right for the other tack.

Think of it as having two mainsails.

A cat ketch with booms would sail identically except there would be something to smack you in the head.

The two sheets on the B&B mizzen can be misleading. The same rig could be used on any small mainsail. It's just a clever way to avoid a traveler or horse, and, since it can be adjusted from either end, it's just handier.

A balanced lug may be MUCH more work to tack. I haven't sailed one, but I understand the sprit has to be "dipped" when either tacking of jibing and it sounds like quite an operation.

What were you thinking??!!! ...just kidding, I definitely am committed to the cat-ketch rig with sprits, but all rigs have strong and weak points.

It's POSSIBLE there are weak points to the cat-ketch, but I can't think of any just now. I'm sure ther are advantages to the balanced lug, but other than allowing the spars to be short enough to be stowed easily in the boat, I can't think of any.

Cheers,

Gordy

[Todd Bradshaw]

You don't need to dip the yard on a balanced lug. Only on a dipping lug, which is a boomless lugsail with the tack corner tied out in front of the mast.

[Dave Williams]

Gordy,

A balanced lug has no sprit. It's upper spar is the yard. And as Todd said does not need to be dipped.

Ron,

The B&B designs of which you speak are sprit boomed cat ketch rigs. A diffenent animal than a spritsail and a very different animal than a balanced lug. They are in my opinion very friendly and efficient rigs.

Anyway, it's all interesting.

Good luck,
Dave

[Gordy]

Todd,
Thanks, as I said, I'm not too familiar with the balanced lug rig.

Dave, You're right, I have a B&B Core Sound 17 with the cat-ketch rig with sprits and it's such an efficient rig and so easy to sail I just can't imagine changing it to something else.

Ron, it seems you've already changed your rig. I think you'll lose some windward ability but you might very well pick up an advantage downwind. The B&B sheet arrangement might make sail control a little handier, but I don't think it will have any effect on your performance.

If you've sailed your boat with the cat-ketch rig, I'd be interested to hear how the two systems compare.

Although those of us here on these pages are rarely wrong, sometimes there's room to be more right.

Gordy

[Ron Hotchin]

Thanks all for trying to help. Todd actually pointed out the difference to me between a sprit boom rig and a sprit rig in a thread about a year ago, redface.gif and helped greatly in developing a balanced lug for my boat. Perhaps this time I can remember it - sprit BOOM, sprit BOOM. There actually are good reasons for the change peculiar to where I sail, but anyone who wants to see the thread can look it up. Anyway, I still don't understand why a sprit boom rig is self tacking compared to, say, a Marconi or Burmudan mainsail of not-so-different shape and size that can gybe like crazy. Is it just that the sprit boom tends to be lighter? I haven't finished my boat yet, but I'll let you know how it does with the lugsail when I get it wet (just the boat, I hope, not the sails).

[Keith Wilson]

Any ordinary sail with a boom is self-tacking if you don't have a jib. Self-tacking just refers to not having to deal with the jib sheets as you tack.

[Todd Bradshaw]

You sure you're not talking about "self-vanging"? That is a characteristic that sprit-boomed sails have which most other types of sails don't share. "Self tacking" just means that you can tack without touching the sheet, which is possible on almost any mainsail and only needs special set-up when applied to a jib-sheeting installation.

On the other hand, if you are sailing for maximum performance, self-tacking sails (or sails that are just left cleated and allowed to self-tack) aren't as efficient as sails that are tended before, during and after a tack.

Boats slow down when they tack. As you start off, after a tack on your new heading, the boat is going slower than it was before the tack. Ideally, the sails should be eased a bit during this slow-speed mode and gradually trimmed-in as the boat picks-up speed. As it approaches cruising speed, the apparent wind will have shifted forward which calls for trimming the sail farther in.

Leaving the sail cleated as the boat tacks and heads off on the new tack (self-tacking) usually means that the sail is over-trimmed and not very efficient during the stage where the boat is not moving very fast. On a jibe, letting a main self-tack can be pretty hard on the rig and sail as well as inefficient. It can also put a pretty good dent in your head if you encounter the boom in the process.

No special mainsheet configuration is needed to self-tack mains on most boats. A cam cleat will do most of the work. If you are using a traveler, it may or may not need to be adjusted with every tack, depending upon how it is set up.

[Ron Hotchin]

This is great, and now I actually understand it. I sailed a Laser for years, and didn't know I had a self-tacking rig! I never considered it to be "self-tending" because as Todd pointed out, you get better performance by adjusting the mainsheet during tacking. I think I was confused by the emphasis of self-tacking by B&B in their literature, thinking it was more than it is. Now I believe I'll keep it simple, and go for one mainsheet for each sail. Thanks again, everyone.
Ron