Boom-end sheeting & sail trim

[bobmcgov]

I generally like the idea of boom-end sheeting, and most of the pocket cruisers I'm shopping for use it. It does bring up certain sail-trim issues, tho. First, it seems like you'll have a ludicrous amount of mainsheet hanging out over the water when running; second, at what point does it really screw up seating arrangements and tiller/outboard access; third, I've heard you can sorta tweak boom-end sheeting to work as a traveller does -- true? & if so, how?

[sailingdog]

Nope... you still need a traveler...

Whether it screws up the seating and tiller access depends on the way the cockpit is laid out.. On my boat, it doesn't really cause any problems.

[Faster]

End of boom sheeting offers more advantages than disadvantages, in my opinion.

It provides better mechanical advantage, and I think its easier on the boom, for example, during an accidental gybe. It's true there is more mainsheet required but the easy access and lack of a winch requirement (boat size is a factor here) makes life easier.

There is some risk of interference with things like lifelines, dodgers, tillers and bodies at times, but as SD says a well designed cockpit can deal with most of these issues.

[nebo]

Ok, I know I don't know much (anything), but I must have missed something here. Faster, what do you mean by a better mechanical advantage? ( I know what the words mean, but I don't see the advantage)

Nebo, the dummy

[justmike]

The mechanical advantage comes from acting on the end rather than the middle, at the cost of requiring greater movement at the point of action to achieve the same angular movement. Think levers. A long lever is easier to move than a short one (assuming all else is the same), but requires you to move the lever further to achieve the same result.

--jmike

[sailingdog]

The center of effort of the main sail is somewhere near the middle of the sail... slightly forward of it. Mid-boom sheeting means you have little more than 1:1 leverage to move the sail...and the loading on the boom at the mid-boom attachment point is extremely high—which makes the boom likely to snap in an bad accidental gybe.

End-boom sheeting means the lever arm you have is at least twice that of a mid-boom sheeting setup, meaning the forces are essentially halved... so you can get away with a smaller mainsheet setup... or with the same size setup, require less force to trim the sail. It is also less likely to break the boom in an accidental gybe.

Originally Posted by nebo

Ok, I know I don't know much (anything), but I must have missed something here. Faster, what do you mean by a better mechanical advantage? ( I know what the words mean, but I don't see the advantage)

Nebo, the dummy

[SanderO]

I've got end boom sheet and a large main, but swept back spreaders so I can get the boom way out to leeward. The main requires 8:1 to be able to move it in stiff breezes. My mainsheet is a combi 8:1 and 4:1. The 8:1 can be used for very fine trim without much effort... but the mainsheet is very long... so for a gybe the 4:1 comes in handy.

The end boom sheeting puts the traveler on the bridgedeck which seems inconvenient. It has some advantages too. I can easily handle it from the helm or in front of the helm... or even on the bridge deck. And I can sit on the bridgedeck and use the sheet like a back rest (on auto pilot of course).

I'm OK with the end boom sheeting.

jev
sv shiva

[maxcontax]

My Catalina 22 has boom-end sheeting and it's great. Not so good for racing but great for what I do which is lazy, cruising sort of stuff. When it gets blowing, you do have a clear cockpit for making fast moves in but in a racer everyone knows what they are doing so that's not at issue. My Beneteau 345 has sheeting on the foredeck, or right in the road. given the stuff I put that boati nto I would not have it any other way. Reason? it is before you, you can adjust the usually neglected traveller much easier than the sheet. Remember, once you set the shape of the sail, the traveller is what you use to change the power of the sail with. Not the Mainsheet. when you mess with the mainsheet, after you have it "set", alot of stuff goes back into play.

In summary, whatever. The Traveller must be considered to be a very integral part of your trim. If you do not know that, try tweaking it with a good mainsheet trim, you could get alot more power from alot less effort.

[bobmcgov]

Thanks for the answers. The boat I'm talking about is a San Juan 21 or similar. So you have a backstay (forked, adjustable), tiller, and (possibly) outboard or troller on the transom; the mainsheet blocks are on the coamings just fore of the transom. Where would a traveller go on something like that (not tangle the tiller)? Could a Barber-hauler sort of thing serve to alter the sheeting angle?

This set-up seems to use a running block on a line as traveller -- but I don't like having the sheet cleated on the cockpit floor. & How would you control traveller location? It would flop from side to side!

[Sailormann]

Get two big blocks of teak and a track. Put one block at the end of each coaming and bolt them onto the boat very tightly. Run the track across the stern from one block to the other. It needs to be four or five inches higher than the tiller.

Use a heavier track than you normally would on a boat this size. Might be a good idea to reinforce it with a strip of stainless underneath to stiffen it.

Put a traveller car on the track and close up the ends. Now get a tiller extension . Shorten your tiller a bit if you like, or just leave it as is, but you want to put the extension socket about midway down your tiller. Make sure that it is one of those omni-directional things that lets the extension handle go every which way.

Now you have a boat with a traveller. It will perform better.