Reading Telltales

[Don Guillette]

Telltales are absolutely the most important sail trim indicator on the boat but sadly a large percentage of boats don't have them (how they trim their sails without them is beyond me) and many boats that do have them, the skippers don't know how to read them.

To those of us that have been sailing for many years, we sometimes don't put ourselves in the place of newbies who are struggling with sail trim. I've spoken with and received a few emails from a newbie lister from Fort Myers, FL. The following is his most recent question:

"Don, I have a question for you. On a beam reach, the jib leeward telltales are all three streaming back horizontal but the windward telltales are streaming vertically up. I have moved the fairleads aft and forward, pulled the jib sheet in and let it out with no luck. The wind was around 4 - 8 mph. So my question is, are the telltales (windward) really an effect on a beam reach? While going to windward (** he means closehauled) I can always get both sides to stream back. What am I doing wrong while on a beam reach?".

First of all, he isn't doing anything wrong and I've already sent him the answer to his question but forum listers can you see how folks learning sail trim struggle with this stuff!!

If you are a NEWBIE or a HIGH BEGINNER, can you answer his question? I know regulars on this forum immediatelly know the answer but I'd like beginners to take a shot at it first.

 

[All U Get]

Hi Don,
The telltales show the flow of air upward so I would think there is twist in the sail. Pulling down on the clew by moving the block forward should do it. If not I tell my wife I'm adjusting undermount clevis and go down below and read your chart. Then I can adjust it right.
All U Get

 

[Don Guillette]

All U Get: You're on the right track to solving the problem - could be the undermount clevis!! - but it's not twist. It does have to do with air flow.

Come on you beginners - take a shot at this!! Think of air flow in a wind tunnel. Picture yourself in the cockpit, like the shipmate from Fort Myers, looking at this problem and trying to solve it and it's driving him crazy because he is trying everything he can think to get those telltales to stream. I'll bet Joe from San Diego, RichH, Stu J, Alan and a few others are chomping at the bit to explain this in two sentences but it is much better if you try to figure it out yourself - then you won't forget it.

Why won't the telltales stream on a beam reach and below??

 

[kgw]

The only way the telltales would stream aft on a beam reach or lower is if your boat is awesomely fast downwind!

 

[Don Guillette]

OK, here's why the telltales won't stream on the point of sail from beam reach and below to DDW. Telltales only work when the sail has wind flowing across it on both sides. On the point of sail lower than beam reach, the sail is not acting like a foil - it is catching the wind like a kite and the boat is being pushed along.

Anytime telltales are jumping up and around they are telling you the wind flow is disturbed and you must make a sail trim adjustment to get both of them flowing. In many cases, you would not even know an adjustment was necessary if you didn't have telltales or, more importantly, know how to read them.

 

[RichH]

The only way the telltales would stream aft on a beam reach or lower is if your boat is awesomely fast downwind!

.... and THAT is your HOMEWORK assignment !!!!!!!!
Quite possible even for 'slow' boats but you have to actually SAIL downwind ... and not simply get 'dragged' by the sails acting as a parachute.
Head up a bit, sail the FASTER course and INCREASE your apparent wind !!!!!!! .... called 'tacking downwind'

 

[OldCat]

OK - I am a little confused here. I am not sure that everyone in this thread is using the term "Beam Reach" in the same manner. As in true wind vs apparent wind beam reach. On a true wind beam reach the apparent wind is still forward of the beam & keeping telltales flowing should be no harder than when going upwind. Except that you may be pushed into vang sheeting when you run out of traveller travel.

At some point as you head down you get down far enough (true wind) then flow cannot be maintained across the sails - thus head up to reattach the flow - I think that this is what Rich is referring to as the fastest way down wind. ??

OC

 

[All U Get]

I always see stuff I read a little different, so beam reach is 90 degrees to the wind like OldCat said and my telltales are doing OK. I got to try it on the water and I'm still not there yet. Today I did learn if you do epoxy while you're in a lazerette, don't sneeze.
All U Get

 

[Joe]

do not confuse points of sail with apparent wind direction.

Boys.... Basic Sailing 101....Old Cat's concern is valid.

Points of sail....( no-sail, close-hauled, close reach, beam reach, broad reach and run)... are always...always... always based on TRUE wind direction. A point of sail describes the boat's orientation to true wind direction. Once a boat starts moving it experiences apparent wind speed and direction. A change in boat speed will change the apparent direction of true wind. Essentially, increased boatspeed moves the apparent wind forward.

So.. sailing on a beam reach does not mean the apparent wind is at 90 degrees. The apparent wind can be well forward of 90 degrees on a beam reach, even a broad reach...

Remember... the wind indicator defines APPARENT wind not point of sail, a point of sail is defined by TRUE wind direction.

As long as you keep the wind indicator forward of 90 degrees you will have good air flow over your sails... and thus the tell tales will function.

 

[Bill Roosa]

I think you are confusing folks Joe.
When you look at the diagram of points of sail I'd agree that that is by definition based on true wind direction. The boat's sails are trimmed based on apparent wind direction. This brings up the point of what do you call it when the boat is trimmed for what in the true wind point of sail diagram is a broad reach but I now don't have a specific term for it because you say that term is ONLY used when talking about true wind.
I think the points of sail are terms that apply to both true wind and apparent wind and the sailor understands which one you mean by the context
Or more succinctly; what do you call it when I'm close hauled under apparent wind? or any other point of sail for that matter?

 

[Bill Roosa]

from Don's post #3
well cause they are lazy SOBs Don and like to relax on down wind runs just like the rest of us.

 

[mcrow33]

Bill, Joe is correct. Point of sail in based on true wind and not apparent wind. If you are sailing close hauled, and your sails are trimed for close hauled. Your wind indicator will be showing apparent wind. If your speed is fast enough the wind indicator will be showing the wind dead ahead. That doesn't mean you are now in irons. When you are beam reach, the waves should be hitting the side of the boat 90 degrees from your heading. The wind indactor will show the wind forward from that point, and broad reach the waves will be hitting the back quarter of the boat. Sail trim is based on these angles, and adjusted as needed.

 

[FourPoints]

To the original question, use of a whisker pole may be needed for points of sail beyond a reach on some boats / genoa sizes. If the fairlead track does not come far enough aft for the size sail you are flying while on a _____ reach, the pole can be used to acheive proper sale shape, and get the tell tails streaming again.

I have a 220% drifter that I use in very light air (under 7kts), but since the clew comes back all the way to the sheet winches (actually slightly past them), I use a snatch block on the stern cleat for a fairlead to run the sheet back forward to the winch, and most shape adjustment is acheived with the whisker pole.

The same principle applies if you have a 155% genoa, with short tracks designed for nothing larger than a 110% genoa, or your sail has a high clew requireing farther aft fairleads than your track can accomidate.

 

[All U Get]

The same principle applies if you have a 155% genoa, with short tracks designed for nothing larger than a 110% genoa, or your sail has a high clew requireing farther aft fairleads than your track can accomidate.

Aha, I either got an idea or the laquer thinner I used on my hair is getting to me. We have a 1.5 oz 130% genoa with ample sunbrella on it. In light winds it is pretty limp hanging out there with heavy sheet attached. My thinking is all that weight distorts the sail shape and we wind up with ho-hum telltales.
All U Get

 

[WayneH]

Aha, I either got an idea or the laquer thinner I used on my hair is getting to me. We have a 1.5 oz 130% genoa with ample sunbrella on it. In light winds it is pretty limp hanging out there with heavy sheet attached. My thinking is all that weight distorts the sail shape and we wind up with ho-hum telltales.
All U Get

No, you haven't been snorting thinner. When I was with a racing crew, we had parachute cord that we attached to the spin under light air conditions and removed both the sheet and the guy from the flying clew. But you have to keep a weather eye out for puffs and filling or you will soon be wishing for a heavy line again.

 

[FourPoints]

My thinking is all that weight distorts the sail shape and we wind up with ho-hum telltales.
All U Get

I think you're thinking correct .

On my drifter I use the smallest sheet line that will fit in my self tailing winches (5/16" I think, but they might even be 1/4"), even though it's the biggest sail I have (excluding the symmetrical spinnaker which I think is slightly larger), and when the air is really light, even that weight will sometimes destroy the sail shape. I have been out before with the water glass calm, hand held anemometer not reading anything apparent (the blades not even spinning), yet still making 1.5kts with the drifter properly pole'd to position. Friend of mine jokes that I have invented a new class of boats with the size of my drifter and the ability to make way under near zero wind.

 

[OldCat]

We have a 1.5 oz 130% genoa with ample sunbrella on it. In light winds it is pretty limp hanging out there with heavy sheet attached. My thinking is all that weight distorts the sail shape and we wind up with ho-hum telltales.
All U Get

Ahhh, Sunbrella. I ordered my new RF 135 Genny without the :cussing: stuff.

IMHO: Sunbrella is great for a sail cover - but not for it to be sewn ON my sail. The Genoa lives under a Sunbrella cover just like the main does. At the cost of a cover - I get a cheaper, better and lighter sail and less chance for the leech to take on a hook:dance:.

OC

 

[Joe]

I think you are confusing folks Joe.
When you look at the diagram of points of sail I'd agree that that is by definition based on true wind direction. The boat's sails are trimmed based on apparent wind direction. This brings up the point of what do you call it when the boat is trimmed for what in the true wind point of sail diagram is a broad reach but I now don't have a specific term for it because you say that term is ONLY used when talking about true wind.
I think the points of sail are terms that apply to both true wind and apparent wind and the sailor understands which one you mean by the context
Or more succinctly; what do you call it when I'm close hauled under apparent wind? or any other point of sail for that matter?

Bill, I am sorry it seems confusing... that's why I don't write sailing instruction books, I guess. But, the statement is this....... points of sail are always referenced to the true wind direction. Apparent wind does not define a point of sail. If you're sailing closehauled you are not talking about the apparent wind direction that your vane indicates, you are talking about sailing as close to the "no-sail" zone as you can without luffing. If the true wind is on the beam you are reaching... no matter what the apparent wind reads.

In any sailing instruction book or class I have taken this concept is always emphatically stressed.

 

[red_dolphin]

Get Apparent Wind Forward!

I think you are confusing folks Joe.

Not at all! Joe has it nailed.

One measure of trimming well is seeing how far forward you can get the apparent wind and still maintain speed -- regardless of the true wind direction.

How you work that apparent wind forward differs depending on your starting point.
On a beat, you 'go through the gears' to get into that 'sweet spot', that 'overdrive'.

On a reach, the same thing happens -- more or less.
Say you tacked around a mark and went from a beat to a broad reach.
Right after the tack you have to trim to the true wind and get the boat going.
As the boat gains speed, the apparent wind moves forward, and you have to trim in.
There will be a 'sweet spot' on a broad reach as well -- harder to find IMO, but there nonetheless.
The telltales will help you find it.

And looking at it from the other side, if the telltales show the apparent wind coming from the beam, the question is [as Peggy Lee once sang], "Is that all there is?"
Can you oooch that apparent wind forward another 5 degrees?
If so, you will be going faster.

The extreme example of this is Ellison's Americas Cup trimaran.
It didn't matter where the wind was coming from, seemed like that boat was always close-hauled.

And as for the question of whether the telltales can be streaming aft on a downwind leg, the answer is, "Yes!"
One of the problems with flying a spinnaker on a Thistle was that the boat would surf down a wave and catch up with its own sail.
Oh, well, I suppose there are worse problems.

And I realize that for this post I was thinking of telltales on the shrouds, not on the sails.
Reading telltales on the sails is much more intricate.
As the OP suggested, telltales do, indeed, tell tales.
I sail mostly on chartered boats.
I really appreciate it when the boat I charter has sails with properly mounted telltales.
That really makes sail trimming so much easier.

 

[OldCat]

OK, here's why the telltales won't stream on the point of sail from beam reach and below to DDW. Telltales only work when the sail has wind flowing across it on both sides. On the point of sail lower than beam reach, the sail is not acting like a foil - it is catching the wind like a kite and the boat is being pushed along.

Anytime telltales are jumping up and around they are telling you the wind flow is disturbed and you must make a sail trim adjustment to get both of them flowing. In many cases, you would not even know an adjustment was necessary if you didn't have telltales or, more importantly, know how to read them.

Don,

After looking at Rich's post that follows this one of yours, I started experimenting. Considering an APPARENT wind beam reach and experimenting with Genoa trim I found that I could maintain a course below 90 degrees dw apparent without stalling the sail. If you sheet the Genoa so the luff is 90 degrees to the boat, then with some angle of attack from the wind, the apparent wind is behind the beam and the leading edge of my Genoa was not stalled per Gentry tufts. I was also able to get it to work with the Genny sheeted out even a bit farther and sail a bit deeper dw with the tell tales still attached.

I don't know about overall efficiency here - I need to add leech telltales to my Genoa - I have no idea if that sail's leech was stalled. The main leech tales continued to draw when sheeted as best I could with the Genoa sheeted as above.

OC

p.s.: I also don't know to what degree this is boat type dependent.