Boom vang snapped off from base of mast

Ken13559 · Sep 25, 2011

pictures of the damaged area/parts would help.

Alan · Sep 26, 2011

Why would you have your vang on while raising the main? Both vang and mainsheet and traveler should be released while hoisting your main. You are fortunate that the mounting failure happened with no load on the sail. The loading on a vang can be substantial so the mounting hardware should be more than just a couple of screws. Tap the mast and use at least four bolts for re-mounting.

tkaser3210 · Sep 26, 2011

Alan - why do you answer a question with a scolding? the attitude that comes across is very condescending - that kind of response makes novices with less experience than you want to keep their questions to themselves

Barnacle Bill · Sep 26, 2011

No better teacher than the school of hard knocks.

Alan · Sep 27, 2011

Sorry you feel that way tkaser3210. I re-read my answer to see if I sounded offensive. If I came across that way it certainly was not intended. If I had been aboard the boat I would have asked the same question at the time. I also would have suggested the info about the control lines. To re-mount the vang properly requires a strong support and this too I would have suggested. I believe that is what Jim was looking for.

Don Guillette · Sep 27, 2011

Jim: It is a simple fix. The way it was previously mounted was with a threaded hole or maybe even pop rivets. Either one is is a poor way to attach the boom vang. The problem with the threaded hole is the thinness of the mast and you're lucky if you get 3 threads.

The attachment method I prefer and used when I was selling and installing Garhauer products was to use RIV-NUTS. Do a google search for more details. They are used in thin attachment situations - light, mirrors on police cars, school buses etc. You can buy them at Harbor Freight but they may not have the larger size you need. They look like a top hat with threads inside. I've never had one pull loose. If it did pull loose it would take a good chunk of the mast with it. If you decide to use RIVNUTS you should check the boom vang attachment points on the boom and I'd replace those also. One other point on re-mounting the boom vang if you decide to do so and that is the boom, while resting on the boom vang should be about 10 degrees above horizontal. That's your setting for very light to light wind conditions. When the wind starts to pipe up a bit you just crank down to the setting you desire for the point of sail and wind condition you're sailing in.

Alan's suggestion is a good one - everything should be loose before you start to raise the main.

I don't know how many ways we can answer questions, especially those of us that get a lot of them. Most times I, and Alan, just tell it like it is. We don't mean to hurt anyones feelings. If we were standing at the YC bar having a "tinney" I'd have asked you the same question Alan did. In fact, any boats I'm on where the skipper invited me because he wanted to improve his sail trim technique, WHY is asked by me a million times. The skipper has to explain to me THE WHY for everything he wants to do and the WHY starts at raising the main and rolling out the jib and goes on until we dock the boat at the end of the session.

dfast7181 · Sep 27, 2011

Don, I have a few questions. I'm still a novice but have taken several ASA sailing courses and have owned a Hunter 33 for about four years and this is the first time I have ever heard of releasing the vang before raising the main. We were tought to loose the main sheet but as for the vang it was never touched during any of our classes. In fact I was once told to set it and forget it, that it wasn't used much, only to keep the sail from raising the boom. so my questions are: 1. Does this apply to a roller furling main also, should you release the vang before you roll out the sail? 2. How about a rigid vang, do you handle it any differently? Just wondering what else I don't know.

Don Guillette · Sep 27, 2011

dfast7181: The piece I'd like to discuss first is "setting and forgetting the boom vang". That's not a good idea and here's why. Let's start with the basics - there are ONLY 4 things that ALL the sail trim controls for the main and jib are adjusting and they are draft depth, draft position, twist and angle of attack. The boom vang is used to adjust two of those element. It's a secondary sail trim control for draft position but it's the PRIMARY sail trim control for adjusting TWIST (the secondary control is the mainsheet). So, if you don't use the boom vang to adjust twist and "set it and forget it" your twist setting is like the broken clock. The setting is right for one point of sail and wind condition and wrong for all others. Same goes for the outhaul and jib fairleads. Some folks "set and forget" those sail trim controls also. The boat SAIL or moves through the water but mates could get much more fun and efficiency out of their boat if they used the controls GOD put on the boat.

Let's say you have a soft vang. The boom is being held up by the topping lift and you've tighten the boom vang so the boom isn't swinging all over the place. If a mate wanted to raise the main with the soft vang tightened he could because the topping lift is controlling the boom. You can only tighten the vang so far. I'd release the vang for the reason I'll explain in a minute.

Let's say you have a rigid vang as I have. The rigid vang is controlling the boom as the boom is just resting on top of it. It's acting as a topping lift. I removed the topping lift because I didn't need it and didn't like it flopping around - it messed up my sail trim karma!!

Let's now deal with the case in point. Say you cranked on the rigid boom vang for some unknown reason prior to raising the main or rolling it out. The boom is probably pointing about 15 degrees below horizontal. As you raise the main it's not a problem UNTIL you get near full hoist. The leech of the sail is being held tight by the boom and you're stretching it to death.

It's tough enough to overcome the friction of raising a heavy sail and the less friction or resistence you have while raising the sail the easier it is.

Try both options (vang on and off) and see which works for you. Actually, I take that back. Release the vang before you hoist the main - your sail will thank you!! Mainly, there is no good reason I can think of to keep it on.

Alan, am I missing anything in this discussion?

Alan · Sep 28, 2011

Nah Don you didn't miss anything, I think you covered it pretty well.

I love the idea of those rivnuts!! I have a problem with the small screw that secures and adjusts the mast gate for my main. The aluminum threads on the mast have finally given way and I've been trying to think of a way to fix this issue. These rivnuts look like just the ticket if they come in the correct size. Thanks

tkaser3210 · Sep 28, 2011

Alan - sorry about the critique - I appreciate your response

Alan · Sep 28, 2011

tkaser3210, no worries skipper. Thanks for keeping me on my toes, I sure wouldn't want to offend anyone with my attempt to answer their question.

Don Guillette · Sep 28, 2011

Alan: The RIVNUTS come in a million sizes. The problem you run into with the bigger sizes is you need a larger "rivnut gun like a over sized pop rivet tool". The advantage I had was a couple of years before I retired I had access to some guys at a school bus garage and they let me borrow the necessary tool. Additionally, when I was re-wiring my battery system they let me borrow an oversize the crimpimg tool, which made the job sooo easy.

Anyway, when you take a look at this product you'll see how effective it is over pop rivets or tapping a thread in a thin mast or boom. I've used them on a lot of boats and I've yet to see one pull out.

Alan · Sep 29, 2011

I checked out the sizes and they are available down to 4mm. I believe I need a 4mm X 1.00 (I think? I'll have to check the size and pitch of the thread on the thumb screw) I do agree they are a great way to mount almost anything on thin walled material. Looks like it will solve this mast gate issue for me.