Maneuverability of Square-Rigged Vessels ?

[HappySeagull]

...and I am really enjoying PjotrC's link...took me awhile to whip the crew into shape(ie:figure out the controls) and still learning to do that but 'tis really absorbing....
I'm glad you brought this subject up,Didz.

[Eleven]

Have you tried the Jiggle Jibe yet, heading closer to the wind to loose speed before hardening the foresails, slacking the spanker, and rudder to turn as quickly as possible.
If this reduces the distance lost by jibing it's a significant improvement.
You can move the islands to make reasonable target paths. And change the sail and mast positions too, when you feel up to it. (This simulation does take huge amounts of time.)

[Didz]

Went into the local libarary yesterday and ordered all the books mentioned so far in this thread. None of them were on the shelves, and a quick check of Amazon and Ebay revealed that those that were for sale were pretty expensive.

[HappySeagull]

Originally Posted by Eleven

Have you tried the Jiggle Jibe yet, heading closer to the wind to loose speed before hardening the foresails, slacking the spanker, and rudder to turn as quickly as possible.If this reduces the distance lost by jibing it's a significant improvement.

Yes ,the shooting upwind I can do but boxhauling
per about halfway through this article
Ocean Navigator | The magazine for long-distance offshore sailing and power voyaging has so far has defeated me exactly.It should be really tight and without gathering too much way,if that's possible.

Originally Posted by Eleven

If this reduces the distance lost by jibing it's a significant improvement.
You can move the islands to make reasonable target paths. And change the sail and mast positions too, when you feel up to it. (This simulation does take huge amounts of time.)

ha!...No, I haven't tried moving islands yet!Fortunately,she seems to plow on through em......Still in beginners mode but I have been able to sail around one,(by ignoring the others!)and I would like to build a brig but accurate proportions are trickier than I thought...I can't be sure they're correct by mere guesswork. .

[Peter S]

One can make everything very complicated but the general idea is the same with every sail driven vessel. For wearing you need to bring your sail pressure as far as possible to the forward. For tacking you need to realize the opposite including sufficient speed of course. A square rigger tacks reliably because one can get the foremost yards through the wind. For this to work it is not even essential to hold the fore stay sails against the wind. Though this does increase the speed of the maneuver. It is not as efficient as a yacht and under usual conditions the vessel looses all speed during the maneuver even going backwards. So much to the theory that motor driven vessels turn slower. The propeller is none the less a major source of drag making it more difficult for motor assisted tall ships to compete with their predecessors.

If anyone is interested the link below describes
a detailed list of procedures to complete maneuvers under sail. Box hauling mentioned previously is very cool. It replaces thrusters under certain wind conditions.
http://www.paulkuiper.nl/EZS/GZV_ZM_zeilmanoeuvres.pdf

[beiland]

Tacking a square rigged Dynarig Catamaran


Here is my initial presentation quite a number of years ago,..
https://www.runningtideyachts.com/dynarig/







I was still working on tacking ideas, and I have some new ones I will bring up if anyone still reads this subject thread,...and are interested.

[beiland]

I did find this posting rather interesting as I read thru the subject discussed here.

Originally Posted by MikeTurner

Bruce, you're correct that many of the old square riggers didn't have a "keel" in the modern sense of the word - certainly nothing like the fin keels modern sailboats have; and no external ballast. They would have the keelson you describe, and some had a "false keel" built below that. I've read that sometime in the 1700s the British Navy experimented with a lifting keel (what we'd call a centerboard I think), but I don't know much about it - O'Brien based one of the ships sailed by Jack Aubrey on this historical experiment.

Techincally, it's more correct to say that a sailboat pivots around a point that is based on the center of effort (CE) of the sailplan and center of lateral resistance (CLR) of the hull. Believe me, I'm no marine architect so perhaps someone else here can give a cogent explanation of this, I'm definitely at the outside edge of my limited knowledge of the physics of this. What I do know is that the CE can shift given the sail set, so the pivot point will vary given what sail is being carried as well as point of sail.

My schooner has a full box keel that encapsulates the majority of my ballast (I have some internal trim ballast) that is shallow draft (2'10"), and a centerboard that functions more like a fin and drops to a maximum of about 6'6". The centerboard isn't ballasted and carries only enough weight to give it negative bouyancy to drop. As it happens, though, we rarely lower the centerboard, mostly due to the shallow conditions we have throughout Mobile Bay. So I'm sailing as a shallow draft full keel boat, albeit one with a much sharper underwater profile than the old full-bodied square riggers.

As is discussed in other posts above, when tacking we first fall off the wind a bit to gain some momentum, and then after turning up backwind the jib in order to bring the boat through the wind - the backwinding helps with the pivoting action. In light winds we sometimes can't make this happen and so have to gybe rather than tack. So my full keel boat does pivot, not as you say around the keel, but rather around the CE/CLR.

I think my point earlier was that the OP was originally asking if a square rigger could turn in a lesser distance than a powerboat. I think the answer is "yes" in some conditions, given the tacking/pivoting action - the powerboat will turn in an arc around it's turning radius, more or less at a constant rate of speed; while the sailboat when tacking will fall off, turn up and through the wind, and fall off on the opposite tack, possibly inside the turning radius of the powerboat. But this doesn't take into account that generally the powerboat will complete its turn in less time than the sailboat will.

[beiland]

It just so happens I was a little concerned about that free standing mast on a big cat with slender hulls,..prone to pitching motions. I found a way to provide some extra security by including a backstay and a forestay,...that would NOT interfere with the rotating yards.

RunningTideYachts.com
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