Safe Working Load on a Mainsheet block

[jonathan_twite]

I am wanting to replace the mainsheet block where the sheet goes to hand, with one that has a swivel built in.  Being a bit tight, I am looking for the cheapest option that will work - does any one know what is the lowest safe working limit required for a N12 mainsheet block?  I have a fairly standard aft-sheeting arrangement, sheet goes from horse to boom to horse to hand.


Thanks

[johnk]

The load on a transom mounted block of the type that you mention will be about 2.25 times the pull of the sheet in your hand. If the maximum load that you can put on the sheet is 50Kg, then the working load is 112.5 Kg. I would hav thought that any block with a safe working load of 200Kg or more would not break. This is roughly equivalent to a breaking load of 400Kg.  If you are using a ratchet block the loads could be higher in a gust. Remember also that the block diameter needs to be sufficiently large for the mainsheet diameter which will be 7 or 8mm.
I hope this helps