Can Double Mainsheet act as a traveller?

[toolarts]

I am the owner of a Rhodes Traveller 32, with it's typical double mainsheet rig.

It has two blocks at the end of the boom and attaches behind the corners of the cockpit coamings.

The double mainsheet is really convenient for tight maneuvering in the harbor. I can use either mainsheet just like a single mainsheet. For reaching and on passages, it is great.

However, no matter what I do, the mainsheets always pull the boom toward the centerline of the boat. There doesn't seem to be any way to harden it down on one side when sailing closer to the wind.

The only places to mount a traveller would be right in front of the companionway on the bridge deck (ugh!!); or on top of the cabin. Since this is a double ender with stern mounted rudder, the tiller sweeps the rest of the cockpit so the bridge deck is about as far back as a traveller could be mounted.

Do I have to install a traveller to get what I want?

Any ideas?

[Ian McColgin]

Moving the sheet to a bridge deck traveler means mid-boom sheeting with three major disadvantages. The leverage is a real disadvantage and the sheet loads are higher. The boom may or may not be designed to withstand the bending stresses. Even if the boom does not break, the leach will go a bit soft which can be designed for, but then y ou're really looking at a different main as well as likely a different boom.

Two tricks help with double ended main sheets. While there's a slight tendency for the boom to creep to center, if you final trim from the leeward side, it'll mostly pull the sail down more than in. And maybe you should have a boom vang or rail mounted boom guys. The latter work well on this boat as the weather guy can be left attached but slack. But it is one more thing to which one must attend when tacking.

G'luck

Ian

[toolarts]

Thanks for the note Ian.

I must have a new boom made anyway so I am not concerned about boom strength.

What about replacing the blocks at the mast with a block + cam cleat arrangement, so that when desired, I could cleat off the mainsheet on one of the blocks to limit it's length?

It seems like this would allow me to pull the main down hard on one side of the boat.

The only complication is I would need to be sure to free the correct mainsheet if the boat were overpowered. This makes for a more complicated situation in an emergency, but perhaps it is acceptable? Then, for tight maneuvering, I just wouldn't use the cleat on the boom block.

However, it also seems like it might be difficult to engage the cam cleat on the block that is moving around and not mounted rigidly. Is there any other kind of cleat or stopper that could be used on the block on the boom to lock down the length of the mainsheet on one side? It seems pretty rube goldberg to me to do this but I can't think of anything else...

Toolarts

[Ian McColgin]

Ahoy Toolarts,

Everything's a trade-off. Some years back I rerigged a Rhodes 40' sloop from an ill-advised midboom traveler on the bridgedeck mainsheet to endboom double ended.

The traveler was a real pain to anyone in the typically small cockpit when tacking. The sheet tended to foul and damage the dodger. It was rigged with a modern complex bi-cam system allowing choise of 3:1 and 6:1, but the 3:1 was too hard to pull in all but the lightest conditions and in many normal conditions 6:1 was too slow. Just plain messy. And it really didn't improve the sail that much anyway as it's still a narrow boat so attempting to take the twist out by the sheet did not do all that much.

Firstly, a boat like this was originally designed to have a heavy solid boom. That's about half your vang right there. Any boom on a biggish boat should be supported anyway. I like quarter lifts worked with lazy-jacks - locally here called LazyIans but I did not invent this - to keep that boom safely up. With a heavy boom this becomes an important safety issue, not just a convenience.

I think if you play with one of those gybe control units - essentially a double sided midboom guy with a bit of drag around the center block under the boom - you'll get all the sail shape flattening you can stand in winds higher than just boom weight can provide. The lowish aspect of these rigs seems to like a bit more twist than you'd want in a high aspect fully-battened blade main.

For safe versitile sail control with managable stresses and loading and cost-effective strong and simple rigging, it's hard for this boat to beat end-boom double-ended sheeting.

G'luck

Ian

[Brion Toss]

Hi there,
That "complex bi-cam" setup happens to be one of my favorite things in the world. Or at least it is when properly used. Bridgedeck travelers are definitely something one has to want to live with, but they tend to be efficient (better vanging than end-boom, more leverage than mid-boom). If there's a dodger in the way, or the crew can't live with it, then it is inappropriate, but that isn't the fault of the tackle setup.
Likewise an insufficiently stiff boom should automatically preclude moving the sheet forward. Perhaps most important, the sheet loads must be calculated to determine if the proposed purchase(s) are appropriate. In the case of that Rhodes, they might not have been. Or it might have been that simply moving the boom attachment point(s) would have brought all into harmony. Or you might have gone with a different purchase entirely, with an option for a winch lead. The point is that the 3:1/6:1 is a tool that is not right for all applications, but wonderful for some (variants, by the way, include 2:1/4:1 and 4:1/8:1).
If you do stay with end-boom sheeting, a vang is indeed a critical component, as the boom departs effective traveler range very quickly. If at all possible, get a to-mast vang, partly so you don't have to tack it, and partly to avoid folding your boom in half with a rail-mounted vang.
Fair leads,
Brion Toss