Traveler - light air

[Don Guillette]

Mates: Do you know when and how much you have to move the traveler to control boatspeed, heel and weather helm? Follow this series and I'll explain how to get the most efficiency from your traveler in light air (2-7knots), middle winds (8 -14 knots) and heavy wind (over 15 knots).Unfortunately, we just can't dwell on the traveler by itself and have to also deal with the mainsheet especially sailing upwind.If you can sail in light wind, you can sail in any wind. The trick in light wind is to get the wind to flow over the sail. The first mistake most beginners and intermediates make is to belly out the sail. Unfortunately, that is exactly the wrong move. You want the sail to be relatively flat because the wind does not have the power to get around a sail with a lot of belly.From this point on I am presenting the infomation from my perspective as the mainsheet/trimmer on a Catalina 30. When I race in the Catalina 30 National events throughout the US that is my crew position. It is also my position on any boat I race on because the jib trimmer job, when done correctly, is too much work!!I've also stated that there is no difference between racing trim and cruising trim. There is only a right way and a wrong way. The racer is going to have to be a bit more diligent but the adjustment he makes are the same. If your a cruiser, just take what I'm saying and sift out what you desire.The first thing I'm trying to do is get the air flowing over the sail so I want to move the traveler to the weather side and to about the center line of the boat. Depending on the boat, I might go a bit higher. Next, I want to crank a bit (but not too much) on the mainsheet to get the top batten on the centerline. What I'm trying to do is get as much air as I can flowing across the sail.How do you know when you cranked too much on the mainsheet? You will see and feel it. The top batten will hook to windward. What you have just done is closed the leech thus stalling the airflow. As a result, your losing lift and the boatspeed will obviously drop. SEE HOW EASY THIS IS TO UNDERSTAND!!I've told you where the traveler should be. Now, where should the boom be? It should be on the centerline or maybe a little above centerline. You have to experiment. The big thing to remember is that you must keep the leech open so that air can flow across the sail. Next, I'll explain how to tack the boat in light air.

 

[Oliverhg]

Clarifications

Thanks for the description Don. I wonder if you can clarify somethings1. Assuming centerline means centerline for the boat, then alighning the top batten with the centerline means the boom is always higher than the centerline?2. You mentioned that you are trying to get as much air flowing "across" the sail as you can. Can I assume that by "across" you mean uniform airflow from top to bottom of the sail and to do so require some twist of the main sail and therefore the line up for the top batten?3. Are you describing a close haul setup or close reach setup? Or are they the same so long as the main is setup before stalling? 4. Is the setup any different for a loose footed maast furling main with no battens?5. The tell tails on my main is almost always curling to leeward unless I let the main out until there is luff on the front third of more of the main. Is the leech too tight?Thanks.

 

[Don Guillette]

Clarification

Oliver: I think by your questions that you have a good grasp of what is going on. your probably almost there but it is hard for me to be specific. Here's the problem I face and it is the same for every author in any magazine or book you read - I'm trying to provide infomation to a wide group of boat owners with every type of boat and sail plan you can imagine from great sails to ones that are almost blown out. I'm working toward the average of all aspects. 1) Yup, centerline means the centerline of the boat. Generally, you want the top batten to aligh with the centerline and what ever you have to do to get it there is the name of the game. I used to race on a Newport 30. To get 100% efficiency from that boat, with the sail he had, the traverler car was about 3' above the centerline and the boom was at least 2' above the centerline.2) Yes, I want as much air flowing across that sail as I can get because there is not much of it. Twist robs power and in light air I don't have a lot to give so you have to mess with it to see what works for you.3) I'm describing closehauled but it does not matter regarding the point of sail. You can not allow that sail to stall and you don't have a lot of wind to play with. As you'll see in the next article - anyone can sail in medium wind. If I fed enough bananas to a monkey, I could train him to sail in medium wind!!!4) Loose footed or bolt rope, battens or no battens, it is the same. A sail is a sail and the way the wind flows over it is the same - remember the wind tunnel analogy because the wind has no idea what it is doing. it just flows over the surface of whatever. 5) Something is wrong with your mainsail trim setup. Are you letting the mainsail out by way of the mainsheet or traveler? The problem with trying to diagnois a problem without seeing it is there are 4 element involved - draft depth, draft position, twist and angle of attack and there are 8 primary controls to adjust the main to handle those 4 elements. All have to be in sync, otherwise it is like trying to adjust a 4 barrel carb by messing with 1 barrel. You can't let the front 1/3 of the sail luff.

 

[Bob]

Other reactions

Certainly I have not written any books, and I always enjoy Don's topics and responses, but sometimes I have a little different take, so here are a relative amateurs responses:1. The top batten will probably have some curvature to it, and if so, the AFT end of the batten should be in line with the centerline of the boat. I believe that most top battens supplied with sails are too stiff for moderate, not to mention light, conditions, and you need to have alternates that are quite a bit more flexible, especially for light air. You'd laugh if I told you what I ended up using for a top batten to get it to bend, but it shapes out beautifully even in heavy air, and I see LOTS of boats that have the top batten absolutely straight when the wind is light. Don, it's really hard for me to imagine a boat that can sail most efficiently with its mainsail cupped - and that Newport had to have some cup in the leech if the boom was that high.2. The top batten should have curvature, just like the bottom batten. The front half should curve more than the back half and the deepest draft should be there. Because the wind is usually stronger up high, you might want to twist the sail to bleed off some of its power or to give the sail a higher angle of attack, since you have what amounts to a 'velocity lift' toward the top of the sail.3. About the only time you want the boom on centerline is when closehauled. As you come off the wind a little, the boom has to come down a little to maintain the same approximate angle of attack to the wind. On a broad reach, the traveler will come down pretty far and the boom will come down an amount that will probably look like too much, but if you are getting good flow across the sail (tell-tales) then you aren't far off. Many sailors sail a reach with the boom too far in. Of course the jib/genoa has to be eased also. You want FLOW across the sails, and the tell-tales are the gauge of that.4. A mast-furling main is going to be more difficult to shape well, period.5. How is your foresail set when this occurs? How the air exits the main is affected by how the jib/genoa is sheeted.

 

[Don Guillette]

Bob: The whole idea of this forum is to get beginner sailors thinking about how to trim their sails. Space does not permit me to provide as much info as I would like plus every boat is a little different but the great thing is over the course of the discussion a great deal of info does come out such as what you are providing about the battens. Most beginners are just happy to get the boat going and be somewhere in the ball park from a sail trim standpoint.The forum is a little like group golf lessons for beginners - a couple of pointers are giving and then the group starts to work on them. Assistents (like you and a few others on this list) go up and down the line working with students on their particular problems and clearing up any misunderstanding that may have come up.It might be hard to imagine how I got that Newport30 to be competitive and I even amazed myself that I could keep the boat in the middle of the pack. The boat owner liked to race and most of the time we were just fooling around and having fun but this boat was a liveaboard to boot and I don't think I ever saw the waterline as it was under water!!Obviously, I'm talking about a closehauled situation. A mate would look pretty silly trying to sail on a beam reach with the boom centered.

 

[Oliverhg]

Thanks for the pointers!

Thanks guys. These are great thoughtsI just came back from sailing today and tried different things. I think the big breakthrough for me is trying to match the main sail twist with the twist on the jib. I had not bothered with that before.The other big discovery is how much draft (2 ft!) I have to creat by letting out the outhaul. Somewhere between the draft and the main sheet, I can now make the tell tales on the main to stream straight which I was not able to do before. I am still seeing a lot of luff (about one quarter to one third) when I let the boom out in order for the tell tails to steam back. I cannot get the tell tails to stream back on light airs with the boom higher than the boat centerline. When the wind is 10 knots or more, the tell tales stream back.I will experiement with halyard tension next.Another question. Why is it that my boat seems to go faster on starboard tack versus porttack? There is about 1.5 to 2 knot difference.My theories1. The wind meter is not calibrated properly on angle and gives me an offset making one tack closer to the wind than the other. I have tried recalibrating the meter over and over by comparing it to the windex on top of the mast but the accuracy is always doubtful.2. Tidal influences. I was sailing across the tidal current so tide current should not be significant to (GPS)speed measurments. However, the tide current may push the keel harder on one tack versus the other. I would guess that tidal current was less than a knot. Can this creat a 2 knot differente in boat speed?3. Boat balance. The boat is likely heavier on the portside and show a 2 or 3 degree list when at rest. I did not think it would be significant to sailing.Is there such a think as a boat that inherently sail better on one side versus the other?My boat is a 33 ft Hunter.Thanks.

 

[Don Guillette]

Thanks for the pointers!

Oliver: Your post makes it all worthwhile. Sometimes I wonder if anyone even reads this stuff but if just a handful of guys get something out of it by trying things and messing with their sail trim controls, like you did, then it makes my day. The "matching" of the shape of the main to that of the jib not only looks great (I love looking at sailboats in front of me when their sails are set properly) but is critical for 100% efficency. Get them out of phase and see what happens to your boat speed.I don't know why some boat sail better on port tack or starboard tack but I know they do. Maybe it is the rigging. I'm not a very scientific guy and, for example, I don't know all the whys and wherefore of the lift/drag ratio but I do know how to make that stuff work for me. Sometimes I cringe when I see technical discussions develop. On one of the first pages of my book I state "if one wants a scientific presentation that include intricate details, together with complicated formulae for hull speed, wave lengths and dispalcement/length ratios plus endless verbiage about these subjects, then this book is not for you". I actually understand that stuff but I can't verbally compete and express myself with the engineers and technical people. Like Dirty Harry said a man has to know his limitations and I do - but put me on a sailboat with them and it is a different matter.