thanks ,now on to nacra rudder system non pivmatic..pull down line to cam cleat on rear beam continuous line,,schock cord up through rudder control arm?Sound right any decent picture will help possable upgrade;;
Re: 7:1 to 8:1 conversion
[Re: Andinista]
#244412 02/21/1211:56 AM02/21/1211:56 AM
Study that diagram closely on how to weave/thread the mainsheet line .... now, if you rotate the single block attached to the camcleat 90*, so that it is orientated ACROSS the axis of the triple and quad blocks, there is a way to weave/thread the mainsheat line w/ no crosses .... so it will operate cleanly ...
Can you fiqure it out??? (Hint: At one point, you will need to thread the mainsheat from the extreme outboard sheave on the Quad Block, down and through the Single Block, and then back up to the other outboard sheave on the Quad Block ...)
Try it ... it works really well, but you need to actually see it/play with-it ... to apprieciate how it works
Note: It works best if the Single Block is the same size sheave as the Triple and Quad Block's sheaves ....
I don't suggest modifying an existing block system. "Upgraded" an 8:1 system to a 9:1, but the existing block hardware was not beefy enough to handle the loads, found out the hard way 3 days into Tybee.
This statement suggests that an increase in purchase means necessarily an increase in max load applied. Is that really true? Don't we want to actually lower the pull to acheive similar results? Therefore more pulleys should mean lower load and not higher, except at the connections in both ends, where the total load is applied.
That's assuming that the goal is to distribute the load rather than apply more total tension. Maybe I'm wrong there.. Still, we are talking about a 10 to 15% increase in purchase, which comes with a decrease in overall efficiency because of the higher friction, therefore, the total tension is increeased in less than that. Would that be enough of an increment to break the blocks? If not rearranging blocks too differently (like the single block suggested in the first post) I think it shoudn't
I agree with Andinista and have recently added another block to my 8:1(even after reading this thread).
Sure i can now probably apply more force, but i don't want to. my goal was to need less strength to sheet to the same amount (i have shoulder issues).
Also i have a hard time believing the sheeting forces are the same on an f18 and n20... but i am not an engineer
Originally Posted by Andinista
Originally Posted by samc99us
I don't suggest modifying an existing block system. "Upgraded" an 8:1 system to a 9:1, but the existing block hardware was not beefy enough to handle the loads, found out the hard way 3 days into Tybee.
This statement suggests that an increase in purchase means necessarily an increase in max load applied. Is that really true? Don't we want to actually lower the pull to acheive similar results? Therefore more pulleys should mean lower load and not higher, except at the connections in both ends, where the total load is applied.
That's assuming that the goal is to distribute the load rather than apply more total tension. Maybe I'm wrong there.. Still, we are talking about a 10 to 15% increase in purchase, which comes with a decrease in overall efficiency because of the higher friction, therefore, the total tension is increeased in less than that. Would that be enough of an increment to break the blocks? If not rearranging blocks too differently (like the single block suggested in the first post) I think it shoudn't
I ordered the quad blocks by the way. The single block idea was probably good but was about half the price, not cheap enough for a probably compromised solution. (That's how I convinced myself anyway..)