New sailor experimenting with sail trim

Stu Jackson · Oct 20, 2011

Do you have a boom vang? Not a boomkicker, different thing.

Stu Jackson · Oct 20, 2011

Actually, in light winds you want a flat sail. Light: flat; medium: fuller; heavy: flat.

Cayennita · Oct 20, 2011

I use a boom kicker in my J-36 when racing to help shape the main. Not to hold the boom up while sailing. Also it is a good item to have if you don't want a topping lift.
You might want to look into twin mainsheets. That way you can move the boom by tightening one while easing the other.
Stu said it right about main sail trim. The bolt rope is not supposed to stretch by itself. It is part of the foot of the main. Tight when going up wind in moderate to heavy. ease slightly when reaching and ease a little bit more when running. I have an 8:1 ratio inside my boom. You probably only need 2:1 in yours.

Don Guillette · Oct 20, 2011

Ross S: It "ain't" much fun trying to learn how to sail all by yourself. I know because that's how I learned. I hate to see mates go through what I went through learning how to sail a silly sailboat.

First, there's very light air and next there's light air and we up from there. How may times have you seen a mate trying to sail in both conditions with a lot of draft depth (belly)? The answer is all the time!! Here's why they set their main and jib that way. They are trying to capture what little wind there is but unfortunately the wind does not have enough power to get around the sails and they stall. So, in VERY LIGHT wind you want the sail as flat as you can get it. As the wind starts to pipe up to LIGHT you want to induce a little (key word) draft depth or belly. What you're doing is starting to POWER UP the sails. Draft depth is your accelerator. As the wind continues to pipe up you gradually induce more belly until the wind gets to about 12 or 15 knots and then you start to gradually flatten (depower) until it almost flat and less powerful. That's what Stu J is explaing to you. So draft depth equates to power. The max draft depth you should induce is 25%. Above 25% the belly becomes counter productive. The Sail Trim Users Guide explains how you make the draft depth percentage calculation.

The above is not a scientific explanation but its what's happeneing. I'm not vey scientific. I just know how to make some of the stuff that happens work for me.

The lack of a traveler isn't a problem but a outhaul that doesn't work is a big problem because the outhaul controls draft depth. What you could do is change to loose footed. You don't have to recut the sail. Just don't feed the bolt rope into the boom slot. One problem with loose footed is that mates induce TOO much draft depth for the condidtions they are sailing in so go easy when you experiment. Apply a little at a time.

The topping lift isn't a sail trim control but you've stumbled on something without knowing it. The main purpose of the topping lift is to hold up the boom when the mainsail is flaked. In very light condidtions it helps if you raise the boom about 10% above horizontal. I don't know why that improve effectiveness but it does. I do know some folks that can explain what's happening and that's RichH, Joe from San Diego, StuJ and a few others.

It's great when couples participate and learn to sail together.

Joe · Oct 20, 2011

I'll just add a bit to what's already been suggested.

First of all, since you have no traveller you must use your vang to control twist on all points of sail. That means you should have the control line in a handy place for quick adjustments.
Be creative when thinking this out. The control line doesn't have to be cleated at the bottom of the mast... you could run the line anywhere before cleating it.

When you're boom sags in the very light air, the leech closes and you have NO twist. I like a little twist in light air, but that's something you can experiment with... so far you've addressed it with the topping lift. I switched to a rigid vang years ago and found it much simpler to manage.... a boom kicker would work well, but the price is similar to the smallest garhauer vang... so I would consider the rigid upgrade.

As far as the outhaul problem, the first thing I'd do is spray the groove with a dry lubricant to see if you can get the rope sliding. If you decide to re rig the sail with the foot out of the boom, pay attention to the small pocket above the foot rope to see if it's filling when you ease the tension. I would also pay attention to the clew slide to make sure it's not overloaded. You could add a second slide, or simply add a lashing through the clew, and around the boom, to give the slide extra support.

cwkemp · Oct 20, 2011

Ross S,
Welcome, and great first post. I sailed on Sacandaga a bit this year. Not a factor this year, but mind the hazard and channel markers when the lake level drops.
Do you have telltales on your sails? Tales on the leach of the main help tremendously in light winds. I'm often surprised at how much twist I need to get them flying when conditions are "light and variable" and I do occasionally use the topping lift to help maintain twist. Also helps to position weight so the boat heels a little to leeward especially when dealing with power boat wakes. Definitely need at least 2:1 purchase for outhaul, especially for flattening when the breeze is up a little. Advice and tips are going to come fast and furious on this forum. Maybe I'll catch you at the I Go Inn next season?
Clint

Stu Jackson · Oct 20, 2011

There are no different sail trims for racers and cruisers. Either you do it right, or don't bother to do it all.

Bill Roosa · Oct 21, 2011

Interesting Don
So you are saying that a very light wind cannot "get around" a sail without it stalling (aeronautical term usage). I’m thinking that I don’t understand what angle of attack you would be suggesting we use in very light wind. My understanding is that angle of attack determines when a “sail” stalls not the velocity of the air moving over it.
From that last statement I’m thinking the angle of attack is “too great” and is causing the sail to stall.
I know that I was taught that you just went from max draft (even sit on the wrong side to induce more draft in a calm) to min draft as the wind speed increases.

On another note: I believe you are seeing an increase in effectiveness when you raise the boom 10 deg above horizontal in very light airs is it increases the draft up high.

Things that make you go “hummmm”

Bill Roosa · Oct 21, 2011

raising the boom also allows twist which decreses the angle of attack up high.

Additional "hummmm"ing

Bill Roosa · Oct 21, 2011

Here is another one Don
It is my belief that most sailors have seen enough pictures of sailboats heeled way over with the boom amidships that they actually think that is what their boat should look like most of the time. Hence they over sheet their sails to "make it look like the pictures"
I have found only one POS and condition that actually warrants the boat being configured/sailed that way; beating to windward in high winds and forgetting to reef.

Thoughts?

What I do in light winds is sit on the downwind side to heel the boat to leeward and get the sail to “fall” and form a VERY cambered surface. I set an initial course into the wind with the wind at 45 degrees from the bow. Since the combination of very light (1-2 knots) wind speed and any boat speed at all will cause a DRAMATIC forward shift in the apparent wind I position the boom to give a 3 degree angle of attack which would be a boom angle of something less 42 degrees due to the high camber in the sail (note AWA is measured from the bow and boom angle is measured from the stern). As I pick up speed and the wind comes forward I traveler (not sheet) in the boom to maintain the proper angle of attack (3 degrees) and fullness. Once I’m making my own wind I can alter course to something more useful to where I want to go.
For the record this is much easier in a dingy than a 40’ sloop but the principal is the same.

Don Guillette · Oct 21, 2011

Here's the problem with pictures in sailing magazines - 8 out of 10 have the crappiest sail shape imaginable. In fact, during sail trim seminars, I use a group of the worst I could find and use them as test material. Participants have to explain what is wrong with the sails and tell me what sail trim controls they'd use to correct the situation plus which way and how much they'd push or pull them.

Don Guillette · Oct 21, 2011

Sometimes on the Sail Trim Forum we make already hard situation harder than they actually are. If a mate can sail his boat in very light to light conditions (1 to 3 knots) he can sail in anything because of one important fact - he has a complete knowledge of ALL the sail trim controls on the main and jib and knows how to make them work together. Additionally, he's using every trick in the book and that includes crew placement, which is leeward/forward. If I fed a monkey enough bananas I could get him to get the boat moving through the water in mid range winds but not in light winds because he's just guessing and not thinking about his sail trim.

The point of sail we're talking about is closehauled. Forget about moving the boat from beam reach to DDW because your drifting - if you're lucky. When sailing closehauled you'd need the boom almost centered and the sail flat. If you ease the boom out (change the angle of attack) and I have no idea why anyone would want to do that, you've made the situation worse and now have two forces working against you. The wind can't get around the sail and it really can't when you ease out the boom. You've just applied the brakes. Add in the fact that you induce draft depth and you'd made the situation impossable.

Where I figured out how to make light air sailing work for me (key words) was racing and cruising in Long Beach, Ca. As Stu J mentioned there is no difference between racing trim and cruising trim - there is only a right way and a wrong way to trim your sails. The Long Beach winds are always light in the morning and then they'd pipe up in the afternoon. I'd watch boats around me to try to determine how they got their boats moving. I discounted the boats without flat sails as they weren't moving. Later I watched the Congressional Cup matched race boat for hours through binnoc's to see how they did it. The turning point was when I got a couple of rides, which wasn't easy, on the Congressional Cup boats. Professional skippers and crews come from all over the world to race on these matched Catalina 37's. I'd hang around the docks and ask a few sail trim questions until finally one of the skippers told me to show up the next day and he's show me how they did it - I almost wet my pants!! While on the boat I'd shut up, WATCH and listen and got to go out the following day also. Then I'd try to duplicate what they did on my boat.

Anyway, sailing in very light to light wind is easy as long as you keep it simple.

Don Guillette · Oct 21, 2011

Ross; Nope, I don't have any sail trim seminars scheduled mainly because there's no money in it. Additionally, if my wife comes with me she spends everything I make shopping!!

I've conducted a shortened version for local YC's such as Tucson YC and Lake Pleasant Sailing Club (Phoenix). The shortened version is 35 minutes and deals only with the "4 elements of sail trim" followed by a Q&A period. My main seminar is 3 hours long with one 15 minute break. It's like getting sail trim info through a fire hose!! In other words, you get everything you need to know about sail trim in one sitting. That seminar is followed by a 4 hour "On The Water Seminar" where they put into practice what they learned in the seminar. Each 4 hour session is limited to 6 people and they go through every position on the boat for every point of sail. The way it works is they bring the boat up to full speed and then the boat is stopped. They change position and I mess up all the controls and we do it again. They have to explain every sail trim adjustment they make. The first hour resembles a Chinese fire drill (actually the Chinese fire drill is better organized!!) but by the 3rd hour they can suggest sail trim corrections for boats sailing near us and tell me exactly why. On the way back to the dock, at the end of the 4th hour, I'll stack their sail trim up against any boat worldwide.

I've also conducted seminars for indivual boat crews but I don't like to do them anymore. The main reason is that if folks don't understand draft depth, draft position, twist and angle of attack and have a small idea as to how all the sail trim controls work I have to waste a lot of time explaining those elements. In other words, I can explain how the outhaul and fairleads work but if the person doesn't know what is being adjusted things get confused. The "On The Water" works best for me because they hit the boat running. They already know what they need to know and are at the intermediate level

Here's a short story that made my day. A couple came to the class room seminar that was sponsored by Marina Sailing, which is a large charter company in So Ca, and sat in the back of the room. They told me they we're ready to give up sailing and only sailed with the main. They were afraid to roll out the jib. Anyway, they sat through the class and signed up for the "On The Water". As soon as we passed the breakwater the next day I assigned positions and the wife's position was driver. She told me she doesn't drive and I told her too bad but you're driving today. As an aside, eventually she got so good at driving that she didn't want to give up the wheel!! She drove back to the dock. When we get back to the dock they both jump immediately off the boat and head up the dock. I thought well you can't win them all over to sailing. About 15 minutes later I see them strolling down the dock with big smiles on their faces. They told me they just chartered a Catalina 30 for the next weekend. That brought a tear to my eye and made my day.

Marina Sailing of Newport Beach, Ca conducts both of the above seminars using my book and chart as their class material. One of their top instructors conducts the classes.

Don Guillette · Oct 21, 2011

I have a lawyer friend from LA, Ca who lurks on the sail trim forum. He never writes anything - he's calls me instead. He's the same guy that told me it wasn't possible to tack a boat under 30 seconds. I told him that 30 seconds is an eternaty and to prove it I asked him to count to 30. At 15 seconds I hung up on him!!

Today he asked (axed me) why can't I just keep it simple and explain what the outhaul and traveler does? I said OK. The traveler adjust the angle of attack. He said what's that in plain English. I disregarded his question and told him the outhaul adjust draft depth and the max amount should be about 25%. He said how much is that in inches and feet instead of using a percentage? Disrgarding and moving on - I axed him if he cared about the various settings for each sail trim control for the main and jib for each point of sail and wind condition but didn't get a straight answer. Lawyers, like politicians, can't give a straight answer. I'm sorry to any lawyers reading this but not to any politicians. Actually, I take that back, I'm not sorry to the lawyers.

My friend sails a BIG Hunter. I don't know how big because I've never been on the boat. Every time I mention going sailing with him I get some excuse, which his wife rolls her eyes with when she hears it, so therefore I don't know how well he sails it but it moves through the water. I love Hunter owners - not so much my friend. I used to think Catalina owners were the group deepest into sail trim but the Hunter folks are more into sail trim than any owners group I've run into - excluding my friend of course.

John, I know you're reading this!!! I told you that you were going to be on the air.

You might think that he won't be my friend anymore but you'd be wrong. He loves this kind of stuff. One more thing - if I ever needed a lawyer I'd hire him.

Gunni · Oct 27, 2011

Hey Ross;
I used to have a Mobjack race boat that also had no rigid vang, a bolt-rope foot, and end of boom sheeting. I added a boomkicker and it did a good job of lifting the boom in light air and allowing the sail to develop a nice draft. They sell them by weight rating, make sure you add in for the weight of the sail, and your running rigging. Going bigger is a good rule of thumb. You can always vang the boom back down. With the outhaul, expect to have to tug the sail back toward the mast to loosen the sail in it's groove, then readjust as necessary.

New sailor experimenting with sail trim

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