Main Sheet arrangements

[neil1967]

The mainsheet on my 25 year old centre cockpit Oyster 406 is attached to the end of the boom and has a 4:1 purchase, which then leads to a winch, behind the helm position. This doesn't feel quite 'right' to me - I would prefer to be able to pull in the mainsheet by hand and then release it when gybing. I suspect I'll need a 6:1 purchase to be able to achieve this, but this would then leave me with a mainsheet of around 35m long, most of which would be in the cockpit when not going downwind. We normally sail 2-up and are not into racing, so simplicity and ease of use are the order of the day. I would be grateful for any thoughts as the best way forward.

Thanks

Neil

 

[Deleted member 36384]

You could rig it up as a 2 speed system. Pull on both ropes for 4:1 or just one for 8:1 (or 3:1 / 6:1). Of course this is double your current rope length. If both sheet tails are even then you will have the same length but a double coil worth of sheet.

Harken diagrams: http://www.harken.com/content.aspx?id=3902

I have a Rival 41C (Centre Cockpit) with a very similar arrangement as yourself. The mainsheet is behind the helm at 6:1 advantage. I just coil it loosely around the winch on the aft cabin roof and find that it doesn't really get in the way. The 6:1 advantage is fast enough for gybing and easy enough to be able to pull in without much effort. From my experience I suggest that you buy the blocks and set it up at 6:1 and see if it works for you, especially before committing to the double blocks.

 

[BAtoo]

For a 40ft boat you could use the 6:1/24:1 version lower down on the harken page.

 

[bedouin]

I would worry about only 6:1 on a boat that size.

There are systems which allow you to do the coarse adjustment at say 4:1 but give you some adjustment at 8:1 ( or more )

That would help reduce the amount of rope, but I've never tried that sort of system

 

[lw395]

I had a 6:1 system with a 4:1 fine tune.
Very nice but you are talking about over £500 in Harken blocks.
Ratchet blocks help a lot.

 

[William_H]

I would have thought the 4to1 with winch the best arrangement. You get easy management with the 4 to 1 for gybing then use the winch to really get the tension on. I really think 6 to 1 will end up wasting too much power in friction and blocks and the twin sheet or tackle on the tail system too cumbersome.
I use a stainless steel wire strop from, boom down to a hanging block to reduce the amount of rope for the main sheet. It works well saving a lot of rope. Set the length of strop so that you get just a short distance between pulleys when the main is in tight. You save 4 times the lenght of the strop in rope. good luck olewill

 

[johnphilip]

How big is the main?
I suspect that as the 406 is masthead the main is proportionately smaller than our fractional rig. Our 33 m2, on a smaller boat, is sheeted at the bridgedeck hence having a less advantageous pull than at the end of the boom. I suspect that the sheet load may be similar. We find that the 6:1 sheet is a good compromise between ease of handling quickly and power to get tight on the beat.

 

[sailorman]

The 406 is a pure cruiser,she will not be short tacking ( well not often) why change the proven layout. Cruising Oysters still have a similar layout, albeit with single spectra mainsheet.

 

[JimC]

I use a stainless steel wire strop from, boom down to a hanging block to reduce the amount of rope for the main sheet. It works well saving a lot of rope. Set the length of strop so that you get just a short distance between pulleys when the main is in tight. You save 4 times the lenght of the strop in rope. good luck olewill

This sounds such a good idea I can't think why it isn't done more often. Are there any drawbacks?

 

[Salty John]

This sounds such a good idea I can't think why it isn't done more often. Are there any drawbacks?

There often isn't enough space to accommodate a worthwhile length of strop - when the traveler is mounted on the main cabin or aft cabin roof, for instance. But an excellent arrangement otherwise.

 

[bedouin]

Set the length of strop so that you get just a short distance between pulleys when the main is in tight. You save 4 times the lenght of the strop in rope. good luck olewill

That helps reduce the length of the mainsheet, but doesn't have any impact of the problem of having several metres spare sheet in the cockpit when close hauled.

 

[AntarcticPilot]

I've done exactly this on my Moody 31. Yes, there's more main-sheet in the cockpit, but I haven't found it a problem. After all, there's always a lot of mainsheet in the cockpit, and moving from 4-1 to 6-1 is only half as much again.

Incidentally, introducing a strop won't make any difference to the amount of rope in the cockpit, though it will shorten the total length of the main-sheet. But think about it; what's in the cockpit is only what is produced by shortening the tackle by the required amount. So, the spare rope in the cockpit is governed by the difference in length between the main-sheet hard in and the main-sheet out as far as it goes. Adding a strop won't change the difference in length; it only changes the total length of rope required for the sheet.

If I wanted more than 6-1, then I'd probably look at a purchase on purchase scheme, with coarse and fine adjustment.

 

[aluijten]

This sounds such a good idea I can't think why it isn't done more often. Are there any drawbacks?

I can think of one drawback in the sense of having a large block flying around at a very dangerous height during a gybe of even during a tack. That is why I would not choose this arrangement. The saving of rope is very real though.

 

[AntarcticPilot]

The saving in rope is real, but small. The length saved is only the length of the strop times the mechanical advantage of the purchase - that is, 4 or 6 times. The saving is unlikely to be enough to compensate for the disadvantage of having low flying blocks! At most you'd be lookin at saving about 10 metres of rope.

Your strop also has to be much stronger than the main-sheet itself - by the same ratio as the advantage of the purchase. You're probably looking at wire or Dyneema or such-like. I'm not sure that having a thin but very strong thing flying around is safe, either.

I can think of one drawback in the sense of having a large block flying around at a very dangerous height during a gybe of even during a tack. That is why I would not choose this arrangement. The saving of rope is very real though.

 

[johnphilip]

I've done exactly this on my Moody 31. Yes, there's more main-sheet in the cockpit, but I haven't found it a problem. After all, there's always a lot of mainsheet in the cockpit, and moving from 4-1 to 6-1 is only half as much again.

Incidentally, introducing a strop won't make any difference to the amount of rope in the cockpit, though it will shorten the total length of the main-sheet. But think about it; what's in the cockpit is only what is produced by shortening the tackle by the required amount. So, the spare rope in the cockpit is governed by the difference in length between the main-sheet hard in and the main-sheet out as far as it goes. Adding a strop won't change the difference in length; it only changes the total length of rope required for the sheet.

If I wanted more than 6-1, then I'd probably look at a purchase on purchase scheme, with coarse and fine adjustment.

I totally agree, a garotte with a hammer end gybing across the cockpit!! our bridgedeck traveller already has issues in this department so why add a hazard? As you say you still have to haul the same amount of rope through the blocks to fill the cockpit.

 

[Dab]

On one large boat I sailed on the cockpit was split into two parts by the traveller. The rear was for the wheel and helm, the forward part for the winches and crew. I think the mainsheet was a 4 to 1 but it came down onto a self tailing winch with its rotating axis paralle to the cockpit sole, it was still pretty long. The easier bits of taking were hand over hand with one turn, as it got more difficults more turns went on and winch handle was applied. When fully in there was a lot sheet in cockpit which was managed with a sot of washboard. The cockpit was failly narrow between the seets, and a a seat height washboad slotted in between some screwed on wooden grooves about 200-300mm in front of the end one which the traveller was mounted. When we finished tweeking the sheet it was flaked down behind teh board in a figure of eight, and where it stayed out of everyones way but was very quick to get to and run out if needed. When in harbour with the sheet tied to the boom out of the way the board could be taken out, giving back some room for relaxing. The winch may be a bit over the top for you, but the washboard stowage was very simple, and should not need to be attached to anything particularly strong.