Just another Moderator
Join Date: Sep 2005
Location: New Westminster, BC
Thanked 357 Times in 337 Posts
Rep Power: 10
Re: Asymmetrical Sail
Assyms (typically a type of spinnaker as jb says above) are usually nylon, whereas a Genoa will be dacron or more exotics if racing. That immediately changes the 'weight' of the material.
The sails have different job descriptions too.. the Genoa is usually the largest headsail you might have, with the smallest usually referred to as the 'jib' or 'working jib'. Smaller still would be a storm jib. You can sail any point of sail with these, but once you start reaching off they become quite inefficient unless it's 'honkin'... Genoas/jibs work best when chosen (size-wise) for the conditions and when sail beam reaching up to close hauled.
Assym spinnaker are usually optimized for beam to broad reaching, full cut but will still suffer when sailing towards DDW as they become blanketed by the mainsail. Biggest advantage and probably the reason for their popularity over a conventional symmetrical spinn is that they do not need a pole, nor the rigging and handling that goes with that. When combined with a 'snuffer' they can be pretty easy to set and douse (as long as the snuffer rigging doesn't get snarled up)
We have both types of spinnaker, and will run the symmetrical if gybing is likely to be necessary, choosing the asymm when we're pretty confident it's a one-tack reach where we're headed.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)