Re: Genoa sheet sizing



Harken has a quick and dirty online calculator for expected sail loads as a function of wind strength here:

The tough part is extending that number to a line size.  Lines are all rated in breaking strength, and translating that to a maximum safe working load isn't so straightforward.  New England Ropes suggests that a safe Working Load Limit 1/5 to 1/12 of the breaking strength of the line.  A range so wide as to not be a lot of help.

Being very conservative, and assuming you carry full 60m^2 of sail in winds of 30 knots, and then reef after that, 14mm looks strong enough to carry the loads without exceeding a reasonable WLL.

It will of course stretch a bit more than 16mm, and then will have less reserve strength as the cover chafes.

I attach my sheets to the head sail with a simple larkshead.  With polyester double braid line it does not slip, and slides past standing rigging without a thought.  The downside is that after sailing a few thousand miles is is REALLY hard to untie.  It can be undone with a hammer and a bit of patience (or a knife)...

We use 16mm headsail sheets on our SM, and have found no incentive to change that, but of course our turning blocks and cars might be different, and your genoa is a bit smaller.  

Bill Kinney
SM160, Harmonie
Fort Lauderdale, FL, USA
Back in the water tomorrow!  Yeah!

---In amelyachtowners@..., <smilesbernard@...> wrote :

Hi there

My Genoa sheets need replacing
Currently I have 16mm polyester
they don’t run too well through the cars, the bowlines tend to get hung up on the lower fwd shrouds when tacking etc.
So am considering other options - a single long line with a single alpine butterfly knot to reduce hangups on the shrouds

My older/vintage Maramu Genoa is I believe around 60m sq. and I’m also wondering if I can move down to 14mm good quality sheets to reduce friction in the cars

Thoughts and experience most appreciated.

All the very best

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