Originally Posted by MedSailor
The mainsheet that came with my boat wasn't long enough to get the boom all the way out.
I've been getting by with a line that I believe is 7/16 stay-set from my old boat.
I'm about to re-lead the mainsheet forward, and back to a winch, and am pricing out the associated hardware. What size, and strength should my mainsheet be? Hardware has "safe working load" stamped on it, but the lines only have %stretch and breaking strength. Any guidelines out there that I can use?
According to Harken's mainsheet load calculator I can expect to frequently be seeing loads of 1,500lbs and see up to 3,000lbs on occasion. With the blocks and deck organizers that I'm looking at, there is a decent size price increase, if I go from blocks that will accept 1/2" line to ones that will accept 5/8" line.
PS. When sizing the safe working load of a deck organizer, does it really need to be able to take the full load? Surely with a 30deg deflection it won't be that severely loaded right?
you must look at all the different componets in your sheet arrangement to get this right.
The load from the load calculator give the load at the fixing point at the boom.
So if you have one block at the boom you should size the block for the load.
I have three blocks at the boom - so the load is divided between those three - each block sized for 50% of the total load (I have a geerman main sheet set up).
At the traveller I have a fiddle block that must take the whole load alone.
A turning block (a block that only change direction of the line w/o gaining advantage) deflecting 180 degrees, need to be sized for double line load (not the boom load) - but it will not increase the load on the rope..
For rope size, handling often is more important to size than strenght. But I would at least have a safety factor of 1:3
If you post i diagram or pictures it's easier to see
what you are planning to do.
A good source for block load's http://www.lewmar.com/cms/assets/1/c...e-tech-ref.pdf
Some figures from my boat:
Mainsheet load 1000kg
Fiddle block at traveller 1000kg
The middle boom block get a load of 500 kg
The other two get 250kg * 141% = 352kg
With a 1:4 system the load on the rope and and cleats/cluthes is 250kg
This is a picture of the turning block at the mast, attached with a Dyneema loop - load 352 kg (block & loop)