Mainsheet doubling

[Kelpie]

Interesing discussion. I have been considering switching to this sort of system myself on our CC Moody. The current arrangement has the sheet going from a fiddle block on the traveller, up to the boom, and then straight to a central turning block and winch. This means that the pull on the boom is always at least 50% coming from the centreline, so the effective width of the traveller is greatly reduced.
My reasoning for switching to a dual-tackle system would be that it would solve the immediate problem, be more reliable and simpler, and free up some deck space aft of the cockpit. It would also allow the boom to be locked in place, and negate the need for a kicker.
I'm not sure whether to dispense with the winch, or to keep it and have less powerful tackles.

[Tomahawk]

Quite a lot of cats, particularly the Catana use the technique

[LadyInBed]

I got to wondering whether to use a quad sheave block on the boom or two doubles. I decided that a quad sheave block is out as it would twist depending on direction of pull, but two doubles would be a tight fit to the boom.
I have decided that the two doubles would need to attach to the boom via a twin tail strop, but wire or dyneema, or maybe a triangular stainless plate would be better?
Your thoughts please.

After thought - If I used a plate like this, to make my sheet continuous I could attach the bitter ends to the centre hole on the plate, saving money on buying double blocks with beckets.
Boom Block Bracket.pngWould the bitter ends get in the way of the blocks?

[LadyInBed]

Do you have a drawing/photo of your traveler setup? Sounds interesting.

I'm not sure it's helpful

Traveler.jpg PS I should have made it clear, the bitter ends are made off to the centre of the traveler.

[mjcoon]

I got to wondering whether to use a quad sheave block on the boom or two doubles. I decided that a quad sheave block is out as it would twist depending on direction of pull, but two doubles would be a tight fit to the boom.
I have decided that the two doubles would need to attach to the boom via a twin tail strop, but wire or dyneema, or maybe a triangular stainless plate would be better?
Your thoughts please.

After thought - If I used a plate like this, to make my sheet continuous I could attach the bitter ends to the centre hole on the plate, saving money on buying double blocks with beckets.
Boom Block Bracket.pngWould the bitter ends get in the way of the blocks?

Unless I'm entirely getting the wrong end of the stick, what is the difference between tying off the "bitter ends" to a plate and having two stopper knots? Surely "continuous" means that there are no ends, just a splice somewhere that runs through all the blocks equally and gets lost? (Which, since I don't think I have encountered such, I suppose means cutting it to, for instance, replace one of the blocks?)

Mike.

[Buck Turgidson]

On a recent long passage I experimented with something similar in concept on my genoa. My Jib cars are the old type, held in place by a pin with no way to adjust from the cockpit and they have seen better days so occasionally needed percussion adjustment with a winch handle. I got round the need to leave the cockpit by using two sheets. One to the car in the fully forward position and a second straight back to the spinnaker block then across the aft deck to the windward block and up to the opposite winch.

With this arrangement I could adjust the tension in 2D without bothering with car adjustment at all. The only downside was when changing tack I had to re-rig it all on the opposite side. As that was once or twice a day it was no problem.

[Poignard]

[...] percussion adjustment [...].

I like that description!

[LadyInBed]

Unless I'm entirely getting the wrong end of the stick, what is the difference between tying off the "bitter ends" to a plate and having two stopper knots? Surely "continuous" means that there are no ends, just a splice somewhere that runs through all the blocks equally and gets lost? (Which, since I don't think I have encountered such, I suppose means cutting it to, for instance, replace one of the blocks?)

Mike.

Apart from a splice enlarging the thickness of the rope, the rope ends have to be eye spliced to either block becets which increases the cost of the blocks attached to the boom or you could use a plate attached to the boom then attach two ordinary blocks to the bottom of the plate along with the two bitter ends. Just a way of saving a few quid! Assuming that you can DIY the plate.