Traveler vs Twin Mainsheets

[sailingdog]

Bob-

You'll probably want to make the line for the double-ended mainsheet a continous loop. Other than that, it seems to be a feasible design. However, the real problem you'll have is fastening the traveller down so that it can take the loads imposed by the mainsheet, since it appears to span the open cockpit. The other problem is that the mainsheet may get in the way of the tiller, since it is forward of the tiller. The only way I can see to avoid that problem is to have the traveler above the working height of the tiller...but then you can't tip the tiller up and out of the cockpit any more.

BTW, the loads on the traveller are generally highest when sailing close-hauled... not running. When you're running, the apparent wind is usually a lot lower than when beating.

[mentalfee]

Thanks for the input so far guys. I will shoot some photos of the cabin top and provide a sketch of what I am thinking with the twin mainsheets. I will be haeding to the boat tomorrow.

I agree the current end boom system is probabaly best in theory but in reality, it is not implemented well on this boat in my opinion. The boom terminates over the steering pedestal and the purchase is dierctly over the helmsperson and on many tacks forces them to the side in a very uncomfortable position. When tacking the mainsheets is running directtly through the helmsperson. If you are not paying attention you can get tangled. Ithink most of you would agree if you were able to stand at the helm.

The other reason, which you all will understand is the admiral says it must go.

Two more posts and I will be able to add photos.

[mentalfee]

One more. Sorry if this breaks any rules.

[mentalfee]

Photo borrowed from another thread. ( I have seen this on Sailnet before so please be kind. I am just looking for the best solution.)
http://www.boatdesign.net/forums/sho...d.php?p=165668

I don't believe there would be any more lines than Gui's setup. It seems to me he too has a mainsheet coming up both star and port sides by his jib sheets. I reailize his is one sheet but both have 2 ends to manage nonetheless.

What advantage do I gain by having a 8 foot spread between ends on the cabin top over a 4foot traveler?


http://www.boatdesign.net/forums/att...7&d=1185013512

[chris_gee]

To keep it simple. The traveller enables the two things of pulling the boom in and pulling it down to be separated. Thus trim and sail shape. If the mainsheet was in the centre ie no traveller you could not pull it in without pulling it down. The 2 sheet system would work but not as well as the traveller as the later has more positions of adjustment.

[Sasha_V]

I can see an advantage is being able to use the twin mainsheets as preventers against accidental jibing... And they are a great way to lock the boom in place so the boom tent / awning really doesn't go anywhere when you are at anchor!

Sasha

[sailingdog]

Sasha-

Whether the mainsheets can be used as preventers really depends on where the mainsheets are anchored to the boat.

Originally Posted by Sasha_V

I can see an advantage is being able to use the twin mainsheets as preventers against accidental jibing... And they are a great way to lock the boom in place so the boom tent / awning really doesn't go anywhere when you are at anchor!

Sasha

[Giulietta]

Originally Posted by bobmcgov

I have questions similar to the OP's. I'd like a traveler to reduce heel and weather helm on this SJ21, and to keep the mainsheet out of the cockpit on runs and deep reaches. The current setup is boom-end; thru dual blocks near the transom on either coaming; then down to a swiveling block with cam cleat on the aft cockpit floor.



If I understand correctly, the traveler performs at least two functions: it lets you vary the angle of the mainsheet, which affects tension on the leech (like a vang) and flatness of the sail; and it changes the point where the boom's upward force is transmitted to the hull.

So in heavy air, moving the traveler outboard means the sheet pulls vertically down hard on the boom, flattening the sail and reducing its power. In return, the boom pulls up hard on the leeward rail, which stands the boat up straighter, reducing heel and weather helm. This lift increases as the traveler moves farther outboard from the mast (centerline).

In light air, pulling the traveler to windward puts the mainsheet at a lower angle, allowing the boom to lift slightly, resulting in a fatter sail when close hauled. Same reason you vang off when pointing in light winds, right? It may also induce a bit of heel, which is desirable on many boats.

Does the above sound anything like correct?

I see alot of hybrid travelers, some of which up attach to the cockpit centerline. While that may place the sheet in your proper hand, won't it also partly reduce the effectiveness of a traveler? Here's one on a San Juan:



It uses 2:1 blocks on a line as the traveler, but then anchors the boom's midpoint to the centerline. Seems to somewhat defeat the purpose. Though it is a handy location.

Sooo.... Keeping in mind I'll have a tiller coming over the transom, what's the best traveler setup for my boat? I'm not keen on putting one mid-boom, across the cockpit. Want to keep a clean seating area. Across the back of the coamings? Right across the transom, blocked way up?

And where should the traveler controls cleat off, esp. for singlehanding in high winds? Does the above "double-ended mainsheet" prototype look feasible?

How far can a traveler beam span unsupported? And how far can it be behind the boom end? The X-shaped tracks claim to resist up to 20 degrees of lateral pull -- but aren't ALL travelers subjected to worse angles than that when running downwind?

Gratzi.

I would not change nothing on your main sheet travel system. Maybe new less friction rope, but I would not change anything.

It seems from the photos you still have some functionality at moving the block in the horizontal line to and from each side. So that is in effect a decent traveller system, just not on a track.

Your notion of traveller service and function just needs a little more reading..

Why would you change it?? leave it as it is..its ok.

[Giulietta]

mental, what you're trying to do is not good for you, its combersome and you will have a lot of trouble when alone.

After you post the photos, we'll look. OK?

Why don't you install a track right in front of the companionway, like this.

Simple and efficient, and pretty reachable by everyone.





If you like this arrangment I can help you with the right materials and specs

Also, have you seen and understood my main sheet system? Do you know how it works?

[JohnRPollard]

I will second Giulietta's suggestion to go with a bridgedeck-mounted traveller if the configuration of your cockpit allows it. It's a very good spot to have a traveller while sailing, and you can unclip the mainsheet and move it to a hardpoint outside the cockpit while anchored -- freeing up the traffic pattern. However, it tends to work best if the boat was designed for it in the first place, with a recessed track pad:


(Pacific Seacraft Crealock 31 Traveller)

I've also sailed extensively on a boat that was equipped with a "Dual Mainsheet" system much like the OP is contemplating. Sailing Dog did a good job of describing the pros and cons. In our case, the system worked very well as a preventer because the mainsheets were hard mounted outboard through the toe-rail (rather than on the coachroof) at a point just aft the maximum beam of the boat. In fact, that was the original intent of the system -- a fixed, permanent preventer. But the whole apparatus worked so well for trimming the mainsail that we pretty much stopped using the standard mainsheet. The preventer/mainsheets were led aft, port and starboard, through fixed turning blocks to the secondary cockpit winches.

That system worked well, but is not as good for obtaining best sail shape and upwind trimming as a well designed traveller system.