Gaff main tell-tales,,,,,,,,,?

[Ian G Wright]

Just had a note from a pal asking me where, on a gaff mains'l, the tell-tales should be.
I have not a clue,,,,,,, I don't think I've ever seen such a thing, though I can't think why not.
Sailmakers advice please. Other opinions also welcome

IanW.

[Todd Bradshaw]

I would suggest three on the leech, 1/4, 1/2 and 3/4 of the way up. The primary advantage of these is that they will tell you when the sail is over-trimmed. When it's under-trimmed, it's usually pretty obvious because the fabric may be distorted and flapping, but when over-trimmed, the sail may look full and fine but actually be stalling out.

On a gaffer, the upper leech telltale will also give you some sort of indication of the effect of gaff sag to leeward. There is always going to be some sail twist up high from gaff sag, but that's acceptable since the apparent wind up there is also shifted around a bit. Since the upper portion of the sail is cut fairly flat, it may not be obvious what is happening up high -overtrimmed? - undertrimmed? - so the telltale on the upper leech is worth having.

Unless you are using a gaff vang (which most people don't, because it's a pain to deal with) chances of offsetting the gaff sag and overtimming the top while sailing to weather are fairly small. Off the wind though, it can happen, especially if a boom vang is in use. This seems awfully complicated for just essentially saying "tie three pieces of yarn to the leech and try to keep them streaming most of the time" but I hope you'll get my drift.

Some people also put a row of telltales (upper, mid and lower) about halfway between the luff and leech or one centrally located one. I haven't found them very useful on cruising boats. I tend to spend too much time trying to get all the telltales flying properly, fooling with the heading and sail trim, and too little time paying attention to the most important task, driving the boat and watching the wind on the water. I figure that if my leech telltales look good and the forward portion of the main looks reasonable, I must be doing something right.