I'm soliciting comments before I build this 9:1 cascade (a higher resolution image is attached):



The things I like about this design are:

• It costs about US$100, since I already have a SailCraft Boom, hexa-cat base, and 3/8" mainsheet.
• All blocks are well within their rated safe working loads, assuming 1250lb total working load. (1250lbs is the SWL rating of the strongest Harken small boat ball bearing traveller car.)
• The sheet loads are perfectly balanced to not twist the boom.
• Line loads are aligned with block sheaves
• Relatively simple construction.
• I can add another cheek block and another 40mm block to convert to perfectly balanced 13:1 for about $25 more. (By cascading a 2:1 into a 6:1, the block loads are much lower than in a 3:1 into 4:1 cascade.)

My only [minor] concern about the sketch is the block at the front of the boom. When the mainsheet is eased to the limit, the load from the primary to this block will be imperfectly aligned. If this proves to be a problem, I will fix it by replacing the cheek block with a single on a very short pigtail in the same position.

Comments?