Importance Of Telltales

[Don Guillette]

Kermit: It pronounce "Gillette" like the blue blade company. I've had to deal with "blue blades" from grammer school - in fact my whole life.

Here's a simple explanation. TWIST is defined as the 'leeward sag of the leech of the sail". No one know what that means. It is better to actually see it. Sit in the cockpit and look up the leech. If the leech forms a straight line there is no twist but if the top 1/3 is pointed away towards the right or left - depending on your point of sail - it is said to be TWISTED OFF or open. If it's a straight line then it's said to be closed.

Make your right hand into a salute and put it in front of your face. Now keep the palm of your hand straight but turn your fingers to the right. Your fingers are "twisted off" or open.

When your main or jib is "twisted" or open, you're spilling power of the top 1/3, which is fine if that's your plan.

You have to see twist once to get it. Actaully, it is easy to see as 70% of the sailors worldwide sail with twisted sails. A lot of the pictures you see in sailing mags show twisted sails. I guess the photographer things its photogenic but it's not very effective. In fact, it's a power robber.

There are 2 mainsail TWIST controls and the primary one is the boom vang. The second one is the mainsheet and since you don't have a boom vang you're stuck with the main sheet. The twist sail trim control for the jib is your fairleads but if you have a fixed fairlead you're stuck.

The topping lift isn't a sail trim control - almost but not exactly. It's used to hold up the boom when the sail is flaked but it does come in handy in very light to light air. When sailing closehauled in those condition, I noticed if I cranked on the topping lift and move the boom about 10 degrees above horizontal I picked up some speed. I didn't break the land sea record but I got the boat moving faster than folks around me.

 

[Phil Herring]

Clarification on tell tales

They're here:

http://shop.sailboatowners.com/cat.php?51900/Tell-Tales

We also have the Wind Tels that Old Cat likes but they were miscategorized (not now). Our prices are a few cents under Defender on some products, a few cents over on other, not enough either way to buy a pack of gum.

Just wanted to correct the record.

 

[OldCat]

They're here:

http://shop.sailboatowners.com/cat.php?51900/Tell-Tales

We also have the Wind Tels that Old Cat likes but they were miscategorized (not now). Our prices are a few cents under Defender on some products, a few cents over on other, not enough either way to buy a pack of gum.

Just wanted to correct the record.

Apologies for my bad search on the first item - trying to sneak a post in whilst the compiler was working away on my poor attempts at code.

OC

 

[Rick D]

Re: Clarification on tell tales

Yes, and I bought some recently and they work great. In fact, much better than the VHS tape and Gorilla tape I was using before!

 

[OldCat]

... Space here does not permit a detailed discussion but here's a small sample. Suppose your sailing along close hauled and your inside jib telltales starts flipping or suppose the outside telltale is flipping - what simple correction can you make to get them streaming? If the inside one is flipping - trim in. If the ouside one is flipping - ease out.

Close hauled?

If the jib is set to the right power for wind and wave conditions - why not steer rather than ease the jib sheet and change the draft and twist of the sail? OK, you can adjust the jib cars...

But CA winds are more stable than mine, which may cause my different perspective on this.

BTW: I would completely agree with you on a reach.

OC

 

[Don Guillette]

Oldcat: You can trim to the wind or trim to the direction your sailing. If youu want to maintain your direction you have to ease in or out. If your just out for a cruise with no particular destination then you can trim by turning the boat. Either way works.

 

[Indysailor]

As a relative new comer to sailing, I would say that tell tales have taught me a lot. Didn't have them on my boat at first, but when I had my genoa repaired and a new main, I made sure to have them included.

What I've found is that the tell tales are teaching me to let my sails out more than I did when I first started, especially on the head sail. "When in doubt, let it out", seems to work pretty well.

I don't have a traveler or a boom vang, so I can't address twist very much, but still there are times when even with the amount of twist I have, the tell tales on the main can stream back nice and smooth.

 

[Don Guillette]

Indysailor: A traveler may not be that important on your boat because you can use the mainsheet. On boats above 30' I would not say that.

You should consider adding a simple boom vang. It doesn't need to be a heavy duty setup - a light weight one would work. Once you install the boom vang you can check it out about 1 minute after you install it. Raise the main and then sit in the cockpit and look up the leech of the sail. It's probably twisted off - in other words the bottom 2/3 of the sail is straight and the top is turned out to the right or left. Set your right hand as if you were going to salute. Now turn your fingers to the right but keep your palm straight - that's twist, which you probably know, but mates following this thread may not.

Next, crank on the boom vang and watch the top 1/3 of the mainsail. With a boom vang you can dial in and dial out the amount of twist you desire.

 

[Indysailor]

No traveler in the future for our boat. It doesn't seem worth it on a craft primarily meant to transport beer and offspring to swimming coves.
However, a boom vang is definitely on my list of things. I have actually pulled down on the boom manually and marveled at the difference in the sail's shape, convincing me that it would be an appropriate addition to the boat.

Thanks for maintaining these sail trim threads. It helps a lot.

 

[Webone]

I have a 150 genoa and can never seem to quite get the lee side telltale to stream properly. even with the fairlead all the way aft the leach seems to tighten before the foot tightens, i.e. can not seem to get a good angle on the sheet to tighten the foot. Is this sail cut wrong?

 

[Don Guillette]

There is probably nothing wrong with the cut of the sail. I assume we're talking closehauled - do you have inside or outside tracks? The inside tracks are used for closehauled work and the outside tracks are for all other points of sail. If you don't have inside tracks, try gragging the sheet and pulling it in toward the cabin top, like a barberhaule, and see what happens.

Think of the front edge of the sail as a knife in a smoke wind tunnel. The blade should cut the wind so the smoke flows evenly on each side. That is what your telltale is telling you, as you probably already know, when it breaks loose and flips. Somethings off but the good news is that it's easily fixed. A 150 is a big mother sail to be messing with but both sides should flow.

 

[RichH]

I have a 150 genoa and can never seem to quite get the lee side telltale to stream properly. even with the fairlead all the way aft the leach seems to tighten before the foot tightens, i.e. can not seem to get a good angle on the sheet to tighten the foot. Is this sail cut wrong?

Several possibilities will prevent you from adequately gaining the correct tension along the foot of a jib/genoa:
1. the genoa track is too short.
2. the mast is raked too far forward (geometrically raises the clew)
3. the genoa is not attached directly to the stem connection but rather has a rope 'pendent' between the tack and the stem connection .... usually put there to raise the genoa from the deck for 'visibility' enhancement under the foot.
4. the Clew is cut toooo high (a 'yankee' type sail).

A. Cursory check of 'geometry' -----
• Check first that mast is either raked aft or 'straight up' but NOT raked forward!
• On a windless day, raise or unfurl the genoa with the TACK of the sail fastened AS LOW AS POSSIBLE TO THE DECK, the genoa track's fairlead car ALL THE WAY AFT, then pull in on the sheet. With full tension on the jibsheet winch that foot of the sail should be taught (and the foot in a 'straight line' from the tack to clew) and the leech should still have some slack in it .... if not then the sail is too big, or the clew is toooo high, or that mast is raked too far forward to carry this sail.
Rx:
1. get a longer genoa fairlead track
2. use a smaller LP sail (or if the sail is on a 'furler' ... sail on a beat only with the sail partly rolled up.
3. Have the TACK section recut, cutting (maybe) several FEET of luff length away ... so that the CLEW is closer to the deck near the fairlead car --- sailmaker will have to 'visit' the boat and physically measure.
If the sail's tack connection is not AT the deck or directly connected to a the furlingt drum (if you have furling), move that 'rope' between the stem connection and the tack of the sail to the TOP of the sail's head, then raise the sail.
If the mast is raked FORWARD .... get back to me as there is probably another problem going on and we can further discuss.

Questions?
•Is this sail on a 'furler'? and if so is there a lot of 'connection parts/plates' between the bottom of the furling drum and the deck? ... the furler a recent addition?
•Does this sail attach to the forestay with 'piston hanks'? If so, is there a 'rope' inside a sleeve at the luff? and is there an exposed 'bunch of 'knots' controlling the tension in that 'rope in a sleeve'?
•Is there an added 'rope' between the tack of the sail and the furler/stem?
•Is the mast raked 'forward'?
•Was this sail 'modified' from a hank-on connection system to a 'furler' system that was added later?

Initially the sail seems to be 'too big' (for the length of present genoa track), or the tack (and or clew) is 'too high' from the deck ... . What say you?
;-)

 

[Webone]

The sail came with the boat ( purchased last year), I only have one track and it already comes back to about 2 feet forward of the winch. I have a hydraulic backstay tensioner and have tried all positions with it. The clew is attached to the furler drum with a short (1 foot) cable which allows it to come above the bow rail, but I can see it might be too high, however, if it was lower then the foot would be "draped" over the bow rail/life lines at some point. Will try rolling it in some and see what happens. I have gotten 8.5 knots out of it close hauled but it is frustrating to see the tales not streaming nicely and in light air I know I am loosing some power.
I will try your suggestion of attaching clew to lowest point and see if I can get the foot to tighten before the leach.
\Thanks.

 

[RichH]

...... (clew) is attached to the furler drum with a short (1 foot) cable which allows it to come above the bow rail, but I can see it might be too high, however, if it was lower then the foot would be "draped" over the bow rail/life lines at some point. Will try rolling it in some and see what happens.
\Thanks.

Tack is what connects to the furler/deck. Clew is what connects to the jib sheets.
Many times the foot of a genoa will get 'draped' over lifelines, especially just aft of the pulpit. With '2-line' lifelines you can modify the 'very forward section' by releasing where the 'top' line connects to the pulpit and then connect it where the 'lower' line connects .... both life lines connect at the 'lower' connection point on the pulpit - but usually needs some alteration of the length of the 'top' lifeline, etc.

The usual 'problem' seen or visualized with/by tell tales in 'light winds' is: too much draft at 'midcord' causing an invisible separation stall - you may need to radically 'flatten' by extra tight winch pressure on the jibsheets - but dont overdo the winch pressure or you will 'bow/sag' the forestay which causes the sail to go draft-aft and the leech to hook up to weather which will also tend to close the slot. In light winds, If those midcord leeside tell tales are not flowing aft ... then the sail simply is not 'lifting'.

Advanced analysis/discussion:
The airstream flow is not 'equal' on both sides of a sail but rather the 'actual' flow (when the boatspeed is subtracted from observation) 'circulates around' the sail. A much larger 'amount' of air is going aft on the leeside .... and/but a 'smaller amount (in comparison to the leeside) is moving FORWARD on the windward side. This is why the wind seems almost stopped in the slot and why 'just before' the sail 'luffs' at its front edge the windward side mid-cord tell tales will be seen to be streaming 'forward'. If you raise a sail with the boat tied to a dock and trim/shape correctly you will really SEE this 'circulation flow' if you have tell tales .... all wings, sails, keels, turbine blades, etc. have this 'circulation flow' when operating at correct aerodynamic/hydrodynamic flow.
.... is this 'forward streaming' tell tale condition what you are concerned about? .... if so, this is normal and the windward side 'flow' can be seen to be apparently 'going forward' (?????!!!!!!) ... exactly when the sail shape and trim are correctly optimized (combination of boat speed and pointing angle ... or sailing a VMG course) when pointing is AT its most efficient setting. Only when 'footing off' below absolute optimum (optimum is at maximum 'lift', not maximum speed ... maximum speed would be analogous to an aircraft in a very shallow dive) will the flow on the windward side visually or 'apparently' be seen to be flowing 'aft' .... and there is a lot of unseen 'mathematics of aerodynamics' going on.
For 'simplicity sake', just be sure you have a full set of tell tales ... and use/refer to Don's Sail Trim Users Guide etc. to get the proper trim settings, etc.

 

[Webone]

This weekend I lowered the tack attachment point and see much improvement. Telltales streaming nicely. Thanks for the input.

 

[Don Guillette]

Webone: Thank you for getting back to us with your successful result - I wish more listers followed your example.

As you've seen, forum contributors like RichH, Alan, Joe from San Diego, Stu J, Scott and a few others put a lot of time and effort into answering questions from beginners to intermediates. Obviously, those guys already know what they are doing from a sail trim standpoint so it's a labor of love on their part. They all like giving something back to the sport, which has given a lot of joy and satisfaction to us, BUT we also like to hear that our suggestions worked.

Now that you're one of us - pass your knowledge on to your sailing friends and dock neighbors. You don't have to tell them where you obtain the sail trim knowledge - they'll just think your a telltale genius!!!