Tell Tale Challenges

D

ds_stanger

New Member
Hi All

OK. Got out quite a bit today. Tried the triangular tell tale set-up in the second panel. Strangely enough windward tales consistently hanging and flicking downwards. Very unusual. I played around with the controls to no avail. They seemed to respond normally just pointing the wrong way!?

Can it just be the length of the telltales? Perhaps they're a little long but nothing exceptional.

Any ideas?

Today was say, 8-10 knots. Outhaul norm at hand width. Main block to block + a few inches.

Thanks.
 
Merrily said:
What do the telltales look like when you've hooked the top battens too much? Under what circumstances do you want some hook?
Click to expand...

If the trailing edge it curved too sharply to windward then the leeward side flow can't follow the sail and becomes detached some distance ahead of the leech. This forms an eddy (area of reverse circulation) that pulls the telltale onto the back side of the sail. It's also known as a "trailing edge stall", as opposed to the "leading edge stall" that you can see with tell-tales at the front of the sail.

Nothing particularly unique with Lasers, although fixing the problem is hampered by the interrelationship of the (few) sail-shape controls that the Laser has.

Hopefully someone with more Laser-specific sail-trim experience can add to my somewhat lacking answer.

Cheers,

Geoff S.
 
I use leech tales. I find them only useful in very light winds while close hauled, or light to medium range winds while reaching. I think the problem is the top batten of a laser is too stiff to make the best shape for the sail. This causes hook whether you want it or not and the trademark creases at the fwd end of the batten turn up as soon as you apply the vang.

Given the other ways of depowering a sail, why would you theroetically ruin the top 1/3 of a laser sail with an over stiff batten? Someone must know the guys who designed it, ask them why. Might have something to do with the OD feature of laser sailing: Best of all worlds, but not especially good for any.

The upper third is so flat it more or less negates the use of tell tales up there. Unless the laser mast was 100ft high, and the wind was 25-30knots up there and 15knots nearer see level, I don't know of a reason why you'd purposely seek out a flatter more hooked shape up top compared to lower down in the sail.
 
Re. stalled tell tales windward side: I think I just have them too far down (about 10" above the window for the bottom 2 tales of the triangle). So I'll try one say, 8" down from the panel 2/3 seam and give that a whirl). Does this make sense?

Re. leach tales. I've been trying one about 10" back from the leach in panel 3. Despite loose vang and maxing by the lee (any further I jibe) I'm getting some vortexing on the back side. Essentially they are not both streaming backwards. Maybe I'll try moving them towards the luff a bit more, say 12-14"....
 
Chainsaw said:
I use leech tales. I find them only useful in very light winds while close hauled, or light to medium range winds while reaching. I think the problem is the top batten of a laser is too stiff to make the best shape for the sail. This causes hook whether you want it or not and the trademark creases at the fwd end of the batten turn up as soon as you apply the vang.
Click to expand...

My observations/feelings exactly. There are times you just have to ignore (all the) tell tales on a Laser because "that's just the way the sail is gonna look".

For BTL sailing, I generally check the mid-sail telltales, but not often - usually I'm too busy keeping the boat at the right heel-angle and trying to setup for the next wave.

Cheers.

Geoff S.
 
You must log in or register to reply here.

Back
Top