Loose Clew On Mail Sail

[Sailavie1]

I spotted this photo of a roller furling main rig with a very loose clew. The jib and main appear to be setup nicely in alignment. This has me thinking (which at times can lead to trouble) why more loose footed mains can’t be set this way. Or is this a bad idea?

 

[capta]

We adjust the outhaul tension our RF main often, see the pic alongside this post. The only time it is strapped in tight is if we are hard on the wind. However, if we ease the outhaul the block running along the boom will go forward keeping the clew closer to the boom (and more in control?), unlike the pictured Irwin.

 

[jssailem]

why more loose footed mains can’t be set this way.

No reason I know that you can not trim your sail in this fashion. You will need to have the rigging set up for that trim.

Look closely you’ll see that the outhaul Block has slid forward towards the mast. Most outhaul blocks are configured to run line along the boom. In the loose trim condition shown the outhaul is riding on the outside edge of the block pulling the sheave sideways. Producing wear on the edge of the sheave, friction on the outhaul line (chafe), and causing difficulty in making any adjustment to the outhaul.

Add a snap on turning block to the end of the boom and you could correct these issues. Will need some additional length to your outhaul line and you have a new way to trim your main for a long broad reach in a strong trade breeze.

 

[BudGates]

Some boats, such as the Hobie Island series, are intended to sail with a loose clew. In shifty wind conditions a loose clew can to help avoid many of the problems associated with an accidental jibe. Optimal sail trim, however, becomes quite difficult.

 

[markwbird]

That is a setup for a windy day. By easing the clew that way they are putting lots of twist in the sail, essentially flagging the upper part of the sail and lowering the center of force and depowering. Normally I would get that shape by moving the traveler to windward and easing the mainsheet and Vang.

 

[BarryL]

Hey,

Why is that better than just easing the main sheet and letting the boom out?

Barry

 

[markwbird]

I just noticed the main sail has a sun cover on the leech and foot. I have never seen that before even with a roller furled main.

 

[capta]

I just noticed the main sail has a sun cover on the leech and foot. I have never seen that before even with a roller furled main.

I do believe that what we are looking at is a standard RF foil installed aft of the mast, which is why we see the sun covers. Our mizzen is like this with the appropriate covers since it doesn't go into the mast.

 

[markwbird]

Hey,

Why is that better than just easing the main sheet and letting the boom out?

Barry

Easing the main sheet lets out the whole sail which may not be what you want if you are sailing on a close reach. keeping the boom centered and easing the outhaul add twist which eases the top of the sail while keeping the lower part in tighter. Less power.

 

[thinwater]

Geometrically, there is absolutely no difference between the picture and a sail with the outhaul eased and the sheet eased. Just imagine a line connecting the tack with the clew, and this is obvious. The only difference is whether the line is between the boom and the clew of the boom and the traveler.

Just less control, that is all. Anyone who has sailed with a boomless main knows this. The only advantage is that only one adjustment needs to be made to go from windward to reaching trim, simplifying things, but the control is less. This is why boomless mains are not very popular.