Does anyone know of a good quick system to dump the main with a double mainsheet syst

[Franziska]

Hi,

I have a double mainsheet system ( tackle from the boom clew to portside deck & tackle from boom clew to starboard deck ) on my 35ft cat.

While initially not very fond of it (two sheets to use :-( ) I like it more and more for its simplicity and low budget hardware.
It also gives quite good control over the mainsail twist.

Retrofitting a traveller system would mean approx 2000€ or more after all.
I was considering it, as previous boats I owned had it.

Now the question to the other double mainsheet people here.
How do you overcome the issue that it is hard to dump the main rapidly in an emergency or sudden squall if you have two mainsheets?
I am single-handing a fair bit.

Do you rely on a rope fuse with a defined breaking strength?
Do you keep a razor sharp knife ready?
Do you have a short dump line with quick release pin between boom and sheets?
Anything else?

As usual many thanks for your thoughts!

The crowd knows a lot but in the end one needs to take ones own decisions!

Franziska

[TeddyDiver]

Propably not possible with your main but if it were a loose footed main and have the outhaul (without horse!) lead into cockpit you could just let it out and forget the sheets..

[cwyckham]

I have a double mainsheet system and I like it.

Have you ever actually had the problem of dumping it? I can't quite picture the problem.

I have both sheets led to cam cleats on the cabin top. If I'm close hauled, both sheets will have tension. However, if I reach forward and flick the windward sheet out of the cleat, the boom will both drop down to leeward and lift.

This is equivalent to both letting down the traveler and easing the main and will instantly depower the main.

When close reaching, if the boom is close to the leeward sheet's hard point, then I can see needing to release both to depower, but it isn't too hard to reach over to the second one. In this case, you're close to needing the vang anyways, so you may want to use the vang for sail shape and only one sheet for boom position.

[Franziska]

Hi.

Thanks for the answer.
Currently my sheets are clamped on the lower end of the tackles.
3m from the boats centerline to port and starboard respectively.

Running them to a midship cam cleat sounds like an interesting thought.

[Franziska]

Here a pic on the deck.

[Factor]

I am not directly familiar with your boat or system, but on Lightwave Cats (the australian production builder) the double mainsheet system works exceedingly well, and you only have to drop the windward sheet to de- power and once done, the leeward sheet is easy to drop. I have also experienced a twin sheet system on a crowther and an arber, both had the sheets coming back through cam cleats to a central winch in one case and winches in the other, again easy to drop the windward one.

[Franziska]

Thinking about it,the primary issue is that the cleats are not reached fast enough.
They are 6m apart.
Guess that needs to change.
Perhaps with a winch....

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[cwyckham]

You only need to reach the windward cleat.

I'm on a monohull, so they're much closer together, but if you remove the cleat from the bottom of the block and move it closer to the helm or crew position, then you'll have the confidence that you can get there quickly.

[44'cruisingcat]

Originally Posted by Franziska

Thinking about it,the primary issue is that the cleats are not reached fast enough.
They are 6m apart.
Guess that needs to change.
Perhaps with a winch....

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Yeah, just move the camcleats. I have the camcleats for the two traveller control lines and the mainsheet all together at the centre of the rear beam.

[Cavalier MK2]

I installed a Chris White designed system and have been testing it out. It uses a centerline mounted mainsheet and a vang/preventer that goes from the boom on each side out to the beam, through blocks and back to a cleat by the mainsheet. Only one cleat is needed because it uses a continuous line.. Just one tackle needed but it works much like the double mainsheet approach. I posted a sketch and write up on the Searunner thread. I like it, nice not to have to rig a preventer. I agree that for the most part, just dumping the windward mainsheet should be enough on a double system but having the cams close to each other will let you dump the lee mainsheet easily too. Reef for the gusts is the rule I use for safety.

[Cavalier MK2]

There are a couple handling things I like on the center mainsheet with the outboard vang/preventer system. Short tacking is easy because the mainsheet can be set and forget. The other is in jibing, I just tried this over the weekend first sail with the system. In moderate air the mainsheet can be left out/extended and the boom moved across quickly and easily using the vang/preventer only. I seem to be doing more singlehanded sailing too so look for the ways to make things easier.

[kas_1611]

One of those things you don't think about unless you have to do it in anger isn't it.

We have a similar system which was labelled as "German Mainsheet" but I doubt it actually has anything to do with Germany. It works very well as a cruising system once you get used to it and has the benefit of having a built in backup and a built in gybe reducer. As our lower pulleys are mounted quite far apart (as much travel as you would get with most traveller systems) we have a far amount of give in the system in case of an emergency dump. Our winches and camlocks are either side of the hatchway, all sheets/halyards are run to the cockpit and we have an in mast furling main.

I'll have to test the theory but my thinking is if we had to dump the main in a real hurry it would go something like this:

Release the windward sheet
Reach over and let the leeward sheet off
Release the kicker sheet (which is normally just on the camlock)
Release the outhaul (as the kicker this is normally just on the camlock)

With all 4 sheets free the main would just flap freely. If required we could then furl in as much sail as needed to reduce power or to reduce the amount of flapping. To furl it properly is a slightly different prospect but once the boat is in irons it's not a major issue.

Good question and thank you for raising it.

Keiron

[Franziska]

Hi.

Thinking about the whole setup, I could just reverse the sheets, get rid of the camcleats on the (now upper) blocks and lead the sheets forward along the boom and then onto the roof to two jammers or camcleats.

If in doubt I could then use the two winches I have already on the roof.

That way the main load is taken by the current outer padeyes on deck and the boom end.

So it's along the German mainsheet system (which got apparently invented for/by the German Admirals Cup team in the 80ies) but keeps the current double mainsheet system with its advantages to a large amount.

Thanks for all your thoughts!

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[cwyckham]

Beware reversing the blocks. One of the blocks has a becket on it that the end of the rope attaches to. This is usually the block on deck. If you switch them, you lose some mechanical advantage. You may want to add a turning block on the boom instead.

[Franziska]

Thanks, I will reverse but use some spare blocks I have.Still might reduce the number of purchases and use the winch instead.Less friction than, and shorter purchase.

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