Mainsheet systems

[jpay]

Hello,
Student loan approaches and my project is getting closer to the water.

I need a mainsheet system and this is something I should buy.
I've only ever sailed centre main systems before.

I have an alacrity and they are aft main on a horse, this is missing.

What is the cheapest way of converting to a centre main? Buy one of these, rivet a block onto the boom?




Thanks

 

[wiggy]

That would do it. If you fitted another block to the cockpit sole and went from boom to cockpit sole to boom and then down throught the block you show it would give more purchase but need more rope.

 

[PeterWright]

Hi jpay,

Just becuse you've only sailed centre main boats in the past doesn't make you incapable of learning to sail with an aft main sheet. On a cruising yacht, the crew and helm don't remain continuouly in the same positions, just swapping from side to side each time they tack, as dinghy crews tend to. People are moving about, swapping helm or going below to attend to navigation, put the kettle on etc. so an extra obstruction / trip hazard on the cockpit sole can quickly become unwelcome. You will also find that, in a gybe, a centre cockpit main sheet tends to lasso anyone sitting ahead of it. If you can get the main sheet up on to the coachroof all this is avoided, but cockpit centre mains are generally not found in cruising yachts. I would recommend that you try sailing the boat with the designed main sheeting system before deciding on mods. In a dinghy, the key difference between using centre and aft mainsheet systems is when you tack / gybe; for centre main you turn facing forward as you cross the boat and for aft main systems you face aft.

If you wish to go ahead with a centre main in line with your question, it can be done, but you will need a slightly different fitting from the one in your post. The type you need will have a becket above the block to which the bitter end of the mainsheet is made fast. The sheet is then rove to pass forward through the block on the boom then aft through the block on the lower fitting emerging through the cam cleat. To achieve wiggy's greater purchase option, I would use the fitting you picture with a tandem block and a block with becket at the boom. Take care with how you rivet the block to the boom; ideally you want the block to hang from a strap which is riveted to both sides of the boom, so that the rivets are loaded in shear If you just rivet it to the bottom of the boom, the sheet load will tend to pull the rivets out.

Hope this helps.

 

[VicS]

For an Alacrity stick with the existing mainsheet horse.

Centre sheeting will get in the way of the companionway.

For a much higher performance boat a traveller on a full width track across the front end of the cockpit would give improved control of sail shape but OTT for an Alacrity

 

[Leighb]

While I would agree with the posts suggesting he should stick to the original layout I understood from the OP's post that the original kit including the horse is missing?

If so he has to build something from scratch and centre main might be easiest/cheapest.

 

[Daydream believer]

swop the horse for a rope bridle??

The fitting will not work on the cockpit floor as the lead out is designed for a horizontal pull as on a dinghy
you would be better with a pulley with the cleat mounted on the block so as you pull up the sheet goes into the cleat & as the main goes out the pulley angles to suit

 

[VicS]

swop the horse for a rope bridle??

The fitting will not work on the cockpit floor as the lead out is designed for a horizontal pull as on a dinghy
you would be better with a pulley with the cleat mounted on the block so as you pull up the sheet goes into the cleat & as the main goes out the pulley angles to suit

Funny you should mention a rope bridle. I did a Google search for mainsheet horse and found some diagrams of my own !

 

[PetiteFleur]

My boats have in order - rear mainsheet; rear mainsheet; centre mainsheet just abaft the companionway; aft mainsheet. I much prefer aft mainsheet - the centre mainsheet is potentially dangerous and I would not have a boat with it again. Saying all that, my friend has a double mainsheet just forward of the sprayhood and this is excellent - no chance of getting caught up in it but with the added disadvantage of extra rope in the cockpit.

 

[DaveS]

The three boats I've owned to date had respectively an aft mainsheet, a centre mainsheet, and a mainsheet on a track on the bridge deck. The aft mainsheet was on a Vivacity, so very like the designed arrangement for the OP's boat. It had the advantage of keeping the cockpit clear, and was mechanically efficient, but involved quite a lot of line which, in the event of an inadvertent gybe could sweep the cockpit potentially lassoing crew.

The Etap 22 had a centre mainsheet which got in the way a bit, but was a fairly minor inconvenience overall. I reduced the amount of string by adding a wire strop to the cockpit sole attachment which brought the lower blocks higher. This also made operating the cleat easier.

My current Etap 30 has a traveller on the bridge deck. Very ergonomic for single handing, and having got used to tweaking the traveller I would now hate to loose this control. The mainsheet is arranged with a choice of 3 or 6 to 1 gearing which initially had a lot of friction, but this was largely removed by re-reeving with a thinner diameter line - probably the most cost effective performance improvement I've made to the boat. The obvious downside is that the sheet crosses the companionway, but in practice this has never caused an issue. On a boat with a large crew it might.