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Tell-tales - not exactly how I expected
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Author:  leecea [ Tue Jun 20, 2017 6:37 pm ]
Post subject:  Tell-tales - not exactly how I expected

My wife and I were sailing in moderate winds on a close-hauled course and I noticed that the windward tell-tale was streaming up and the leeward was streaming back. I pulled in the sail and both streamed back nicely but I felt the boat slow down. Just my gut feel, since I had no GPS. I let the sail out again and it felt like we sped back up. I have heard this is normal if you're flying a hull because of the sail's angle from vertical, but we had both hulls in water, with a slight lean. I repeated this a few times and always got the same result.

Am I doing something wrong or is this normal?

(In case it matters, I had my downhaul as tight as I could make it and my battens are not very tight. I have the mast raked to hole 9 of a 10-hole adjuster.)

Author:  Tom Kirkman [ Wed Jun 21, 2017 2:35 pm ]
Post subject:  Re: Tell-tales - not exactly how I expected

You will likely find your best speed and sail trim to be when the leeward TT is streaming straight back and the windward TT is mostly streaming back, but quivering just a tad and occasionally flipping upward.

...............

Author:  leecea [ Wed Jun 21, 2017 3:12 pm ]
Post subject:  Re: Tell-tales - not exactly how I expected

Thanks. I just ordered some more to put on the leach too - hopefully I can get better at trimming.

Author:  mmiller [ Tue Jun 27, 2017 8:37 am ]
Post subject:  Re: Tell-tales - not exactly how I expected

This is a good guide:

Quote:
Tell Tails are used for a variety of wind indications:

Up high on the top of the mast or on a support stay (shrouds, forestays and bridles on catamarans), would be free to indicate apparent wind direction and undisturbed by the sails.

In the body of the sail to indicate air flow over the sail surface.

On the leech of the sail help to indicate under or over sheeting as well as sail twist.

We simply place the basic sail body ones as a starter. These are the most common used in sailing. I like the leech tails and always have a free swinging wind indicator if I'm racing. I have a couple of diagrams that might help. Designed for Catamarans, but really similar on all sails.

How to place them:
Image


How to use them:
Image

The basics are to try and get both standard tells flowing. I would rather see the windward one stall than the lee side. Sheet out or change course until they flow. Then sheet in a bit.

The upper 3rd of the sail is a good location for "leech" tell tails. If you sheet too hard the tell tail will wrap to the lee side. Not sheeting hard enough and the tell tail flows straight aft. The right sheet tension typically causes the tell tails to flow aft then wrap to lee and repeat... alternating. Very difficult to get it all flowing correctly on a Kayak sail due to the limited tension and sheeting controls and no traveler. Catamarans have battens, downhaul, outhaul, and travelers on the sheeting systems... all work together to trim properly for different points of sail (directions you are sailing compared to the wind).

Author:  srm [ Tue Jun 27, 2017 12:27 pm ]
Post subject:  Re: Tell-tales - not exactly how I expected

leecea wrote:
I pulled in the sail and both streamed back nicely but I felt the boat slow down....I let the sail out again and it felt like we sped back up. I have heard this is normal if you're flying a hull because of the sail's angle from vertical, but we had both hulls in water, with a slight lean. I repeated this a few times and always got the same result.


Where are the telltails located on the sail? My recollection of the Wave sail is that the stock position is with them located at about the center of the sail (vertically) and about 1/3rd of the way back.

My guess would be that when you sheeted in, you got the telltails to flow, but you were actually stalling out the top of the sail which was why you felt the speed drop. Sails stall from the top down, but since you don't have telltails up there (I'm assuming), you didn't visually see the stall. I'd recommend placing one set of telltails about 1/4 to 1/3rd of the way down from the top of the sail.

leecea wrote:
Thanks. I just ordered some more to put on the leach too - hopefully I can get better at trimming.


I've never found leech telltails to be of much use. As I said, I would recommend one set up high and one set at about the middle of the sail. Be careful of adding too many sets as you will just end up with information overload.

sm

Author:  mmiller [ Tue Jun 27, 2017 12:55 pm ]
Post subject:  Re: Tell-tales - not exactly how I expected

Quote:
I've never found leech telltails to be of much use.


Leech tails are critical to optimum performance. Easy to use. Keeps you from over sheeting.

Author:  leecea [ Wed Jun 28, 2017 6:36 am ]
Post subject:  Re: Tell-tales - not exactly how I expected

Thanks for the help. I'll add one more set as srm suggested and then focus on trying to read them in different conditions.

Author:  srm [ Wed Jun 28, 2017 6:49 am ]
Post subject:  Re: Tell-tales - not exactly how I expected

mmiller wrote:
Quote:
I've never found leech telltails to be of much use.


Leech tails are critical to optimum performance. Easy to use. Keeps you from over sheeting.


Personal choice I suppose. I've been sailing/racing Hobies (and other boats) for 30 years and never really used leech telltails. I find that having one set in the first or second panel from the top of the sail works best for me. Sails stall from the tip down and from the leech forward so either location will work, but I prefer to just use the upper set.

sm

Author:  mmiller [ Thu Jun 29, 2017 8:06 am ]
Post subject:  Re: Tell-tales - not exactly how I expected

Quote:
for 30 years and never really used leech telltails


I guess it's a racer thing. If you want to win races...

Author:  tgrahmann [ Tue Aug 13, 2019 2:34 pm ]
Post subject:  Re: Tell-tales - not exactly how I expected

Apologies for resurrecting this thread but I have the EXACT same question and don't feel that I have a full understanding of the issue...

As a new sailor that just started into some beer can regattas I'm trying to take some lessons from dinghies back to my Hobie 16 to maximize speed before the next few racing opportunities come up.

I frequently experience the same phenomenon when pointing. Approximately 40 degrees off true wind, jib halyard tight, downhaul on strong to move draft to 1/3rd forward and sheeted nearly block to block with a 6:1 harken, boat speed at least 5 - 7 mph. The tell tales on the windward side of the luff are still flying straight up, but the leech tell tails are hooking to windward pretty strong.

I've noticed that when sheeting out some in this condition there is an immediate acceleration, likely from increasing the depth of the mainsail as it was pretty flattened out. Leech tell tails flew back a little straighter and hooked less.

Is this just a matter of the apparent wind moving forward enough to start to stall the windward luff tell tails?
Does this just happen with increased speed?
Or is the mast creating some backwinding (it is rotated all the way to the lee mast stop) and my luff tell tails are too close to the mast (8-12 inches back)?

Should I ignore them and just pay attention to boat feel and leech tell tails?

Author:  mmiller [ Tue Aug 13, 2019 3:23 pm ]
Post subject:  Re: Tell-tales - not exactly how I expected

You need to get the jib sheeting figured out. Clew plate attachment point changes the shape of the jib leech. It should closely match the main shape, so the wind is not pinched off or the slot too open/closed. This may take some time viewing from the lee side up into the slot for the best effect. That can be a hazard if you don't have a crew that can do it or can take the helm while you look.

Once that is known... then:

When close-hauled you have to pay attention to the jib tails for proper boat angle of attack (sheet the jib to a fixed tension for pointing) and then the leech tails for fine-tuning the main. Scanning both constantly. Jib to see that you are not pinching... then main leech tails to be sure you don't over/under sheet the main.

Author:  tgrahmann [ Tue Aug 13, 2019 4:43 pm ]
Post subject:  Re: Tell-tales - not exactly how I expected

To my recollection the jib tell tails were always flat back with the windward flicking up 5 to 20 percent of the time. Well trimmed to my understanding. Jib leech is pretty straight and tight, no obvious scalloping or wrinkles. I must confess that I don't well understand the slot adjustment and how it should be fine tuned, but typically it is kept in the tightest position to the mast. Only on broad reaches do I ever move the jib track out.

If you have a reference to proper slot adjustment I'd appreciate it.

After that, like you said, rely on the leech tell tails more than the luff tail tells for fine trimming?

Author:  mmiller [ Wed Aug 14, 2019 8:33 am ]
Post subject:  Re: Tell-tales - not exactly how I expected

The slot - When you sight from the lee side aft looking forward into the slot (while sailing to weather), between the jib and main... the curve shape of the main should be matched by the jib leech shape more or less. If pinched closed, high or low, it restricts the airflow over the main. Move the clew attachment down to open the top of the slot... move the attachment up the clew plate to close the top and open the bottom. Over sheeting closes the slot. That is learned by trial and error, feeling the speed changes.

Author:  tgrahmann [ Wed Aug 14, 2019 9:15 am ]
Post subject:  Re: Tell-tales - not exactly how I expected

thanks matt

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