Sail Trim Too (Two!!)

[Ed Nye]

The sail trim discussion was good, but really didn't address my questions. Gentlemen may not sail to weather, but I want to, or at least do the best she will do. So I'll try to ask the right question this time.
From my racing experience, you need to see both tails (windward and leeward) on a jib/foresail. Windward should be flicking up (not stuck there) and leeward streaming aft. My problem is you can't see through tanbark sails and adding windows is not an option. So I want to know, if I add tails to the leach, will that help determine proper trim and if so, what should the tail on the leach look like?
Ed
:confused:

[ 09-18-2003, 11:46 AM: Message edited by: Ed Nye ]

[Venchka]

Originally posted by Ed Nye:
...My problem is you can't see through tanbark sails ... if I add tails to the leach...

Ed
:confused: Ah, well, now that is a horse of a differnent color, eh?

Dunno :confused:

Where is Todd Bradshaw when we need him?

[ 09-18-2003, 12:10 PM: Message edited by: Venchka ]

[Todd Bradshaw]

It's still morning and I'm slowly re-animating... I've never tried leech telltales on a jib, but suspect they won't help a lot. You really want to know what's happening to the flow before it gets to the leech and the air that far back is likely to already be pretty streamlined due to the slot effect. You can still usually see black telltales through tanbark some of the time, though not always. If you can't find black ones, let me know and I'll cut you some. Since the burning issue here is the jib/main interaction and the possibility that the distortion in the main luff is due to it being backwinded by the jib, the more critical jib telltales are going to be those to windward, indicating over-trimming, so even if you can't always see the leeward ones, adding telltales still may help.

EDIT: If you want to try leech telltales to see what happens, I just use a hot-cut strip of spinnaker fabric about 3/8" by about 8". I cut a circle of peel-and-stick Dacron about 1.5" diameter and cut a short slit partly across it's middle. Stick the telltale through the slit far enough that the stick-um captures it's end and fold the patch over the leech with the slit along the leech edge. You can make a more traditional one by just poking a hole in the leech with a sail needle and threading a bit of yarn through the hole with a stopper knot on it's end. As mentioned before though, you can expect the yarn to be hung-up on the leech stitching about 25% of the time.

[ 09-18-2003, 12:35 PM: Message edited by: Todd Bradshaw ]

[Art Read]

Ed, no, I don't think a telltail at the leach would give you the information you need. Some people like 'em on the leech of their main to proove they aren't "cupping" the leach, but what you really want on the jib is something telling you what's happening at the leading edge. I can't remember a sail that I couldn't see at least a faint shadow of the leeward telltale thru the fabric, but then I'm not sure I've ever even SEEN telltales on tanbark sails! (Maybe that's why?) The good news is that the windward telltale is the most usefull one anyway, and you should always be able to see that. If you watch what's going on from a vantage point where you CAN see both sides, (standing by the forestay with someone else at the helm, perhaps?) you'll notice that as you fall off the wind just 'till that windward telltale streams straight aft, your lee one will be taking care of itself. It will only "break" when you keep falling off suficiently to interupt the airflow on the lee side of the jib. A fairly significant course change, (maybe 5 or 10 degrees?) on most boats. So, while sailing yourself, just pinch up into the wind enough to make your WINDWARD telltale "break", (the one you CAN see) then fall off just enough to bring it back in line and there you are! (Should you be so fortunate as to have the wind where you can actualy sail the course you want, then you'd "trim" for the telltales with the jib's sheet once the boat is on her heading...) I suspect you'll find that "pinching her" enough to keep the windward telltale "pointing up" will perhaps allow you to point slightly higher, but at the cost of significant boatspeed. 'Course all this only works for sailing close hauled or on a close reach/beam reach anyway. By the time you've reached a beam reach, your sails are gonna wanna be sheeted out about as far as they ever gonna go anyway, so sailing a broad reach or running, the telltails are kind of pointless anyway. That make any sense? Just give it a try next time you're out on the water. It makes more sense on the boat! It helps to remember that the whole point is to keep the leading edge, (luff) of the sail pointed directly into the apparant wind while sailing "on the wind". (Beam reach, close reach or close hauled) That's all the telltales are "telling" you...

[ 09-18-2003, 01:13 PM: Message edited by: Art Read ]

[Dan McCosh]

The leach telltales will tell you when the airflow breaks on the back of the jib, since the turbulence will cause them to go from streaming back to jumping around or maybe pointing ahead. They won't tell much about a pending luff, since the air at the trailing edge of the inside of the jib stays smooth due to the jib/main slot. One other hand, a pending luff will also be visible on the a sail itselff, since the jib will start to collapse at the leading edge. The leach telltales work on a main since they are clear of the slot, and they can tell a lot about the main trim. All in all, a pending luff really doesn't need telltails to detect it, while a stalling sail isn't nearly as obvious. The jib leach telltales might do some good here.

[Wild Wassa]

Keep the leach telltales streaming. Especially the top one.

Warren.

ps, Do you lube your telltales?