Proper sail trim vs. points of sail for a cat?

[mark_morwood]

Originally Posted by cal40john

I wouldn't use that page. Main traveler 1/3 to weather for a beam reach is just one of several odd ideas about sail trim.

I agree. Unless he also has a vang, he seems to not be using the traveller to control sail shape when upwind, and just letting out the sheet as he comes off a tight reach which lets the boom rise and the sail lose power at the top. On our boat that would be slow - we keep the main sheet relatively tight and drop the traveller as we come down from a tight reach to a reach.

As was already stated, key is keeping the telltales flying, including those on the leach of the main sail to make sure you are not inadvertently over sheeting.

Mark.

[marvinmartian]

Ok, thanks y'all. I think what I originally suspected is true.

My basic question was really looking at how, given the proper angle of the main as defined by any standard "points of sail" diagram, can cats do this since they aren't able to wing out as far.

The answer seems, as best we can. I've observed that letting the main out keeping the traveler mid or even slightly to wind gives me a wider angle towards the middle of the main's curl.

If they could just get rid of the stays and keep the same basic rig. Does make me wonder about things like the twin mast configurations I've seen, not the least of which the new Chris White.

[cal40john]

Originally Posted by marvinmartian

Ok, thanks y'all. I think what I originally suspected is true.

My basic question was really looking at how, given the proper angle of the main as defined by any standard "points of sail" diagram, can cats do this since they aren't able to wing out as far.

The answer seems, as best we can. I've observed that letting the main out keeping the traveler mid or even slightly to wind gives me a wider angle towards the middle of the main's curl.

Your mainsheet is your vang. Your way as the wind varies the boom is going to rise and fall changing how much the sail is trimmed in top relative to bottom changing how much and in which direction the sail is pulling the boat. I'm not sure what you mean by wider angle in the middle or why you would want that.

If they could just get rid of the stays and keep the same basic rig. Does make me wonder about things like the twin mast configurations I've seen, not the least of which the new Chris White

Don't know what boat you have, but normally the stays you are complaining about are what is keeping the mast from falling forward. You can get rid of them, but then you need a backstay, now that you have a backstay you have to get rid of all that sail area in the roach up high on the main. Compromises...
.

The system says my message is too short, I guess I have to put something outside of the quotes.

[robert sailor]

The issue you are talking about is not unique to Cats as most mono hulls are rigged with swept back spreaders and are limited to how far the main can be let out. For all points of sail other than down wind there is no problem but down wind its a compromise but thats life.

[marvinmartian]

The America's Cup team has software to show them via real time overlay the optimal sail shape and angle.

Wonder how hard that would be with some senors, a camera, and an iPad.

Or more precisely, how much might people pay for it? ;-)

[44'cruisingcat]

Originally Posted by marvinmartian

Ok, thanks y'all. I think what I originally suspected is true.

My basic question was really looking at how, given the proper angle of the main as defined by any standard "points of sail" diagram, can cats do this since they aren't able to wing out as far.

The answer seems, as best we can. I've observed that letting the main out keeping the traveler mid or even slightly to wind gives me a wider angle towards the middle of the main's curl.

If they could just get rid of the stays and keep the same basic rig. Does make me wonder about things like the twin mast configurations I've seen, not the least of which the new Chris White.

I'd be careful doing this. You don't want the battens bending around the shrouds. Better to move the traveller down and let the sheet out less.