Fitting a boom vang (kicker)

[Gezzunder]

I'm wondering if any of you knowledgeable folk can give me some tips on installing a boom vang on my boom-vangless yacht. I've read that the ideal angle for a kicker is 45°.

I have a problem that the cabin is built hard against the mast foot, so getting that angle on the boom vang would have the lines rubbing on the fore of the cabin as you will see in the photo...

http://i267.photobucket.com/albums/ii297/darcydugganx/boomvangless.jpg

I was thinking of a lever arm arrangement pivoting from the gooseneck with the blocks pulling at a point along the lever to effect a 45° effort. Would this work or am I barking up the wrong tree?

[Thorne]

A bit more info would be nice -- just how big is the yacht, and how much sail are we talking about controlling? Do you plan on a 4:1 purchase or need more power?

It appears from the photo that your mast is in a tabernacle. If so (or even if not), why not attach the vang up the mast a bit higher? I've also seen vangs attached to the cabin top, so again that option might work if the construction of the cabin allows.

Are your other lines lead aft? If so you may want to do the same with the vang, or at least make it easier to release from the cabintop.

[P.I. Stazzer-Newt]

Take a look a a variety of cruisers - very often the vang assembls sits at a much flatter angle than 45°, There is a trick with a floating lever which is used for large mechanical advantage kickers on dinghies.

The Arc track on a Star is worth a look but that is probably overkill.

[Gezzunder]

She's a 23 footer built in the fifties and I wouldn't, to be honest, have a clue how much sail she has on her at the moment. The plans called for a total of 202 sq ft (145 main and 57 in the staysail) but the original mast was lengthened from 24' to 34' in 1961. I haven't measured the current main. The boom remains her original length of 12' 9".

I intend taking advantage of an existing (welded) fitting on the mast and would prefer not having to fit a new one. If I go higher, wouldn't it also reduce the overall leverage on the boom itself? (The reason for coming up with the lever arm idea)

As for my other lines... I have only three to worry about as she stands. Two of those are on the staysail :) Sailing at it's most basic.

[Brian Palmer]

The lever arrangement that you have drawn appears to be the opposite of how levers are used as vangs on small boats. Instead of applying a 2:1 advantage to the boom, the boom is applying a 2:1 advantage to the base of the mast.

For a decent vang, you need to go farther aft on the boom than you apparently can with the present mast location and cabin profile.

A better arrangement may be to have vangs or "preventers" rigged so you can sheet the boom downward from either side of the cabin top when you are reaching and running downwind. That is when the boom tends to lift and can contribute to rolling and you lose some efficiency in the sail shape. When you are pointing and the boom is sheeted in close to the center line, you should have much less need for a vang.

Brian

[Thorne]

As pointed out above, some vangs are at lesser angles. And since nearly any vang is better than no vang, why not just go with what you can rig up easily? You can always go for a stronger purchase to make up for the lesser angle...

[P.I. Stazzer-Newt]

...You can always go for a stronger purchase to make up for the lesser angle...

There are limits to this kind of behaviour - stuff goes "Twang" or "Creak" - as John discovered when the took the tail of the vang to the spare sheet winch...

[bott]

Not to diverge from the topic too much, but have you considered using an generic kicking strap? Just larks-head a strop around the boom, in a place to lead it downward to an eye on the sheer. Has nearly the same effect as the vang, and then some (preventer...).

But, if you are looking for more draft control from the vang and less twist control, then the kicking strap will be generally less effective.

Just a thought...

[hm0316]

My Luders 16 has a similar restriction created by the cabin. Assuming your boom is wooden, a modern vang will create undue force in a heavy wind and you will risk breaking the boom. A better solution is to put well supported pad eyes near your shrouds on both sides of the boat, put a strap around the boom and use a block and tackle to hold the boom down to the pad eyes. Ideally, you would have separate rigs on each side, with a easily released snap shackle at the boom, so you do not need to drag the gear across the cabin top. On a 23 foot boat you should be able to reach forward to release the shackle from the cockpit. HM0316

[tprice]

The preventer type rig as some described (lead to leeward rail will work fine if you don't mind adjusting it every time you trim your main! And also you have to disconnect it and transfer it across the deck when on the other tack.
Easiest solution is to (as suggested before), simply raise the lower attachment point up and the boom attachment point aft till you get clear of the fwd cabin edge. This shallower angle will rwquire more purchase. Use a cascade system of purchases to increase power.

[gregleeber]

Dood,

its a wooden boat, why would you want a vang? Are you racing?

[Concordia...41]

I think it is Selden or maybe Harken (I'll check and report back) that has a cool upward (from boom up to attachment point up on the mast) vang system.

The other alternative is to draw the boom down to a preventer on each tack. And no, it's not just for racers. You should do the best for your boat and it's control regardless.

[hm0316]

A shallow angle on a boom vang as some have suggested will require greater force on the vang. One responder correctly pointed out that a shallower angle created by moving the point of mast attachment will require a greater "purchase" for this reason. A modern vang attached to the mast will work fine if your boom is either aluminum or carbon fiber. If it is wood, you should consider the use of a preventer type vang described in my prior post as well as others. On a 23 foot boat it is not a particular inconvenience to simple release a shackle when you jibe. As noted previously, it would be best to have two different rigs on each side of the boat rather than pulling the rig across the top of the cabin on each jibe. HM0316

[johnw]

Dude, you don't need a vang, you need a gnav. It's a stick that goes from the mast to the boom to hold the boom down. Nat Herreshoff used them on several of his boats, notably Pleasure, his last one, which had it on the mizzen.

[tprice]

Agree that the Gnav is a good way to go (basically an upside down rigid vang) except that you have to live with some "Sunfishing" of the mainsail on one tack (no big deal as that area isn't particularly productve anyway - in lee of mast/ cunningham, gooseneck etc).
To the salty dog who says you only need a vang if you are racing - I'd say that more pleasure comes from an efficient sail whether you are racing or not (unless the vang breaks your boom!)

[Gezzunder]

Dood,

its a wooden boat, why would you want a vang? Are you racing?

:D Yep. My first race saw me with no batons, no leachline, no wind indication of any kind and a crew of one who had never sailed before. Well we did have a form of wind angle measurement - we both smoke and agreed that we would alternate indulging in the vice and watch the trail from each puff.

It took nearly nine minutes to conduct our first tack, as Russ the Love Muss managed to neatly snare the main halyard cleat on the mast with the leeward jib sheet. He then snared the ventilator on our second tack, but he was getting better... only five minutes for that one. Our first downwind run illuminated the fact that there was not enough main sheet - I could only get the boom about 40° from center but the boat hook made for a nifty whisker on the staysail. Oh well, it's only for fun. Trailing by 20 minutes on the pack is ok for an old girl I thought and we'd only gone out so there'd be more boats in the race.

The Love Muss turns out to be a quick learner, we are tacking with elan now. The wind has picked up nicely and with mast strumming wildly with each flap of the luff and our wake littered with dhurry butts we are hard heeled and scooting along with huge grins on our faces... this is FUN!! Those boats seem closer too.

We cross the line with our trail reduced to just over three minutes. Comparing GPS logs, they had achieved a top speed of 7.4 kts while I had tweaked the old girl to 8.1 kts! Genie really is magic and she will be raced again. The old boys at the clubhouse enthused about how nice an old boat she is and I've been placed on warning to restore her to mint condition.

So I've installed the batons and stuck lots of wool all over her. Adjusted her previously slack rigging (not too much mind, just right) and tripled the main sheet, even sewn a leach line. The Love Muss has been reading "Sailing for Dummies".

Now I'm looking for a little control over sail shape and seeing how much more I can get out of her.

[MiddleAgesMan]

Here's something that might work:

http://www.yachtsandyachting.com/photos/forum/JackSparrow/2008-09-11_142115_DSCF0105.JPG

Instead of pulling down on the boom at a bad angle you pull forward on the bottom end of the V-structure with a short but highly leveraged purchase. It's called a Temple vang IIRC.

[MiddleAgesMan]

If your boat is a classic design you'll not get away with something as high-tech as the above. All I ever used on my old Alberg 30 was a vang-preventer run down to the rail, something that does a very good job but has to be relocated when you tack or jibe.

[tprice]

E scows and Int 210s have that type of lever. I don't think he has enough room between the mast and cabin front for the short leg. They place a mighty load on the gooseneck (as do all vangs).
Here's something that might work:

http://www.yachtsandyachting.com/photos/forum/JackSparrow/2008-09-11_142115_DSCF0105.JPG

Instead of pulling down on the boom at a bad angle you pull forward on the bottom end of the V-structure with a short but highly leveraged purchase. It's called a Temple vang IIRC.

[S/V Laura Ellen]

This is from the Holland Marine Products catalog.

http://www.aylard.ca/Misc/vang.JPG

[johnw]

Careful, you could break your boom. And by the way, if you go the preventer route, be careful not to jibe without releasing it.

[dobrosailor]

I would agree that a vang is great when it blows to flatten the sail and forestall reefing sometimes, but I can't help but point out yet another solution which gets all the boom tackle out of the cockpit and can do the same thing. Mounting a boom travler just over the open cockpit slider door (assuming you have one; to keep from banging heads). This places the main sheet up on deck (out of the cockpit) and depending on where the travler car is you can get a flat or full sailshape combining with main sheet tension. I've done it on three boats; two of which were mine and its great assuming you don't have a prohibitively long boom. It helps to have a block forward and one aft of the travler on the boom to spread out the tension.

Remember, if you are inclined to be forgetful for organic or self inflicted reasons, a vang/preventer can be ill-advised with a wooden boom.

Just a thought...

M