Cruising Chute Sizing

[bobgarrett]

If the distance from where my halyard enters the mast and the top front of my pulpit is 12.24m what length luff should a cruising chute have. I am thinking it does not need to go right to the mast especially if I have a snuffer, equally it should be a bit above the the pulpit, but then it ought to have a bit of extra length so as not to be tight.
Are there any formulae for this as I am looking at second-hand sails.

 

[AIDY]

bob get a spinny instead least you can go down wind

 

[Greenheart]

I was wondering the same thing, this morning. I read a big-name sailmaker's guide to judging asymmetric luff length. They reckoned the straight-line distance between the chute's tack during use, and the point where its halyard emerges from the mast, is the dimension you should quote for the luff.

It surprised me - it sounds too short; but perhaps the chute's billowing fullness isn't so dependent on luff-curvature, as one might have thought.

Quote by AIDY: bob get a spinny instead least you can go down wind

WHY!?! After many long, frustrating, nail-breaking hours of unrewarding attempts to benefit from a regular spinnaker, the asymmetric equivalent is a thrilling, freeing, low-effort, high-output answer. The asymmetric should be essential to every new yacht's basic sail-locker.

Those maniacs, who always naturally choose the hard way, can supplement their boat with a trad spinnaker and pole...and the hideous tangle of control lines. I made damned sure I had one!

 

[bobgarrett]

bob get a spinny instead least you can go down wind

Spinnakers are fun when you have a full crew, which I don't!

 

[ianat182]

When trimming the cruising chute we have the tack rope fitted with a snapshackle through a pulley block at the bow roller position (some boats have a fixed wire strop and no pulley block) Using the tack line we can adjust the tack to the height of the pulpit or slightly above if almost dead down wind, and release the halyard about a foot, taking the sail well forward of the pulpit. With tension kept on both sheets the chute will pass through the gap smoothly as you gybe. if the next course is closer to the wind the halyard is tightened and the tack drawn in to below the pulpit height. We play around with the trimming until the boat speed is as required. Both halyard and tack are played through Spinlock type jammers.


So I reckon that the luff would be OK at the size you've mentioned.

We also have a thin line to release the tack from the cockpit to dowse the chute

ianat182