I'm just about to change my main sheet from a 6:1 to 7:1 and need a triple plus becket at the top block. Has anyone any idea ( or calculated ) of what loadings ie how many kilos are actually at the block as the specs differ widely between sheeve size and manufacturers.

Many manufacturers also quote for example a 650kg working load maximum on their single blocks and yet the same 650kg applies to their triple block, any clues as to how they work out the max loadings. <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" />