Trim question

Bad Obsession · May 10, 2009

The vang is used to control the twist of the mainsail. When sailing downwind it is very important to use the vang as it also keeps the boom held down. With just the main sheet on the boom the boom can rise up some.

David10790 · May 10, 2009

When the mainsail is raised

Is the leach tight when the sail is up - on many (most) boats the leach will lift the end of the boom higher than the topping lift normally holds it. if this is the case for you then yes, the vang will be effective. If however, you find that the leach is loose and the topping lift is holding up the end of the boom to keep it off the bimini, you have a real problem. you will never be able to flatten the sail properly to go upwind, and the vang will just be fighting the topping lift. If this is the case, you need to lower your bimini.

tsmwebb · May 10, 2009

It isn't clear to me what you're asking.

Are you saying that when you are sailing you are using the toppinglift to keep the boom high enough to prevent it from hitting your bimini? Then maybe your question is: is using the vang to pull against the lift a good idea. IMO, probably not brilliant technique but you can get away with it as long as you don't pull so hard that you're tensioning the topper. Better go see you sailmaker for a leach job.

Have you already had the leach shortened so that with the sail up the boom clears the bimini even with the topper released? If so maybe the question is: with the vang at more than a right angle to the boom will the vang still work. Answer: almost certainly. I wouldn't worry about it.

Maybe you're asking something else?

--Tom.

higgs · May 10, 2009

If the topping lift is needed to lift your boom off the bimini when under sail, that is not desirable. I had a similar problem with my boom gallows in light air which was solved by having a little trimmed off the bottom of the sail.

Bad Obsession · May 10, 2009

Higgs is right and so are the other posts. If your sail hangs too low you may need to get it trimmed up a little.

That is why it is best to get a sailmaker to come to your boat and measure stuff instead of just getting pre-made stuff from a factory somewhere because all boats have their own personality, if you know what I mean.

sailingdog · May 10, 2009

If you're using the topping lift to support the boom to clear your bimini, you're going to have lousy sail shape. The mainsail's leech should be supporting the boom, and if your mainsail can't clear the bimini without the topping lift being used, then you either need a shorter bimini or a re-cut mainsail. Using the topping lift to support the boom, you're basically defeating the whole idea of using the boom vang.

biggio said:
My boat is Catalina 27 Tall Rig 86.
Due to the height of of my Bimini top my boom is raised about 3 inches via the topping lift from all the way down.
With the boom raised is the boom vang effective at all?
Could I be stressing the boom unnecessarily by using the vang?

Ron20324 · May 10, 2009

Don't lower the water, raise the bridge... or the sail... I don't suppose you unshackled the tack and raised the main to see if you had any hoist to spare to tighten the sail and leach then slack the topping lift?

higgs · May 10, 2009

Thanks biggio for letting us know you were paying attention. We get a lot of questions here where we wonder if the poster ever listened to the advice. You will get this problem solved one way or another. These are the issues that make sailing fun.

jibes138 · May 12, 2009

Binoculars

Great for watching birds of all types, for use at night to find inlets, and for seeing what is going on at the top of your mast. Take a look with a pair (can be bought for 5 dollars at a 1 dollar store) at the top of your mast to see if the halyard is in fact all the way up. How is the head of your sail attached to the halyard? Sometimes a spliced halyard can be too large for the sheave in the mast and prevent the sail from being raised fully. When you hoist the sail it should lift the boom and detension the topping lift. Before you hooist the sail your vang should be completely loose to allow the sail to go up all the way. A friend once compained he could not raise his sail far enough and the boom rubbed on his dodger. He was making warranty claims to catalina, complaigning to the new boat dealer, etc.. I told him to loosen his vang when raising the sail and his problem was immediately solved. He was one happy camper after that and he bought me a bud light.
Once the halyard is taught with nothing restricting the hoisting of the sail (note the topping lift does not restrict the hoisting, only the vang and mainsheet and cunningham have this capability). So to sum up the plan:
1. Loosen mainsheet considerably.
2. Loosen vang considerably.
3. Loosen cunningham considerably.
3.5 Head straight into the wind.
4. Raise mainsail until luff of sail is appropriately taught for the conditions.
5. Loosen topping lift to allow the sail to fully support the boom in the proper shape, topping lift should have some slack.
5.5. See if boom still hits bimini, if it does shorten bimini or modify sail. If it doesn't...
6. Bear off and make sail adjustments using traveller, sheet, vang, halyard, and cunningham for the conditions and point of sail. Have a wonderful day out sailing.
Regards,
Dave