Window in mainsail?

[Brad]

I'd like to ask opinions on having a window in the mainsail. Why would one want one? I get that they're for looking through, but it seems all I'd see is my genoa. Do they affect performance? Do they affect structural strength? Better for cruising to have one? Better for racing to not have one? Any and all pros and cons welcome.  Also, with the outhaul full on, how close should the clew of the main come to the end of the boom. Thanks all.

 

[Doug T.]

window & outhaul

People put windows in the mail so they can see how the genoa is trimmed. Generally, it's positioned so that one can see where the sail is in relation to the spreader tips while at the helm. The window should be as small as possible because the material is heavier and stretchier than the usual sail material.Can't answer the outhaul question -- it depends very much on the boom and on the sail. You shouldn't trim the outhaul based on absolute position of the clew, but instead should look at the shape of the sail and position of the draft in various wind conditions and at various points of sail. Generally, tighter/flatter when close reaching & looser/fuller while sailing downwind.

 

[Bob Howie]

Windows in sails

More trouble than they are worth, don't last as long as the sail material, will yellow and "craze", become brittle, crack and need replacement. Not in my sails, we don't.