boom vang

[brackish]

Finished building my boom vang including learning how to do the dreaded double braid eye splice (frustrating half rainy day, but last one only took about twenty minutes, think I've got it down).  Buying components and making it up myself saved a lot over getting one premade.



In reading up on installation of the bails, one position is to maintain a forty-five degree angle mast to boom.  Another says mount the boom bail at least 1/3 out on of length of the boom.  Can't do both because of the mast base to boom gooseneck dimension.  Planning to use the mast pivot bolt for the mast base bail and forty-five degrees from there would be too short on the boom, only about 20% out.  Any thoughts or experiences?

Frank 2

[kahpho]

Nice job brackish! The splice looks great! I like your idea of using the mast pivot pin as a mounting point. I might have to use that when I come to making a vang for my boat. But I'll give you credit for the idea, promise, no really...

mel

[Craig Weis]

I purchased a boom vang at the All Sail Boat show years ago. It was sold by Garhauer, an original supplier to Com-Pac Yachts. This particular vang model is a 4 purchase unit.

Thinking long and hard about the installation I came up with the following.

1~In the mast's slot I slid in and dogged down a standard phenolic cleat. As far down as I could place it.
2~This became two things. a-->Provides a tac for the boom's down haul line. Adjust taught only after the main sail is        fully hoisted. b-->This cleat also becomes the tac for the boom vang. The vang is stamped with a angle to fit the          boom.
3~The bail was purchased from West Marine. It was the smallest bail sold and it was too long. I think it had five screw        holes.
4~Being too long I clamped my boom into the shop vice and picked a location on the boom for the bail.
5~With a C-Clamp the screw hole closest hole to the business end of the vang [the tac] was squeezed on to the boom      and marked.
6~Guesstimating the location of the last usuable screw hole an arc was drawn on the vang. The vang was hack sawed        to this shorted length and filed and rounded smooth. Note that the last screw hole MUST NOT enter the rope slot          used for the main sail's foot.
7~Fasteners: Screws I don't like. Aluminum rivets for this job are too soft and can break. I used long steel pop rivets.
8~C-Clamp the first port and starboard hole. Drill and set the first two rivets.
9~Work up to the last hole sinking each rivet.
10~Attach the vang with additional swivel hardware of your choice and the job is done.

Be mindful that the vang's fiddle [cam lock] must be easily reached from the closed companionway hatch. That basically put the bail in the right spot. I had to shorten the Garhauer supplied line. Next time I'd make mine bail about 12" more aft.

Additionally if a short cable is used from the aft standing rigging to the boom's end, the vang must be released to allow the skipper to raise the boom to disconnect the boom from this cable. C-P 16's don't have an aft standing rigging I know.

skip.

[brackish]

after looking at the Harken site, they recommend a 30 degree "minimum" angle, mast to boom.  I think the trig will work out for that to be at least 1/3 of the way down the boom.

Mel, I haven't mounted the mast bail yet but think it will work OK.  Should be enough clearance when I drop the mast to let the bail stay on until the mast is down.  It just happened that one of those fancy boom kicker aluminum bails with a roller shackle fits perfectly on the outside of the mast step and has a clearance hole for a 3/8" bolt.  I just had to buy a longer bolt to accommodate two thicknesses of the bail.

Skip said

Additionally if a short cable is used from the aft standing rigging to the boom's end, the vang must be released to allow the skipper to raise the boom to disconnect the boom from this cable.

added snap shackles to the blocks, so I plan to remove the vang when not actually in use.  I've installed an adjustable topping lift, but still hook up the pigtail when sail is down, flaked and covered.  The vang may also become the motor hoist when necessary.  My boom bail will be installed with a through bolt and a reinforcing aluminum tube to take any additional stress caused by the vang.  I'm assuming nothing in that boom below the foot track for the sail.  Maybe better look at the extrusion profile on the Dwyer site......

[Salty19]

Nice handiwork there Brackish!    I'll be mailing some line to get spliced next week. 

[brackish]

LOL Salty19,  Send it on.  The cuts on my hands should be all healed up by the time it gets here.

[Bob23]

This is all quite interesting and informative, men. But, hey, Skip- steel rivets? (See #7) Sorry, here in salt water land, that's a  no-no. I use strictly ss machine screws, drilled and tapped and installed with Never-Seize graphite grease. No corrosion and it can always be removed. Shoot, I even use Never-Seize on my underwater shackes. They can be taken apart even after being under salt water for 2 years. Don't you wish things in Washington worked so well?
Bob23

[bmiller]

I agree with Bob. Anything attached to my mast or boom gets a threaded SS machine screw. Not only will they last but in the event something needs to be removed, replaced, repaired it's much easier with threaded fastners.
Just be sure you are confidant in your drilling/tapping abilities. Buy the best quality drill bits tap available, it's cheaper in the long run and makes the job much easier. Plus you get a much better finished product.  I got a little cocky and sloppy tapping for my boom kicker. Snap went the tap. It's now a permanent fixture on the lower mast.
Speaking of boom kickers anybody else use one?

[kahpho]

I have a question for all you rigging modifiers. Are the aluminum mast and boom walls really thick enough to hold a threaded fastener reliably? That is drilled and tapped for a screw without a nut to back it up? I guess it must be if you all have been doing it that way without problems of pull out. What size fastener do you generally use? Fine thread, course thread? Does it hold up well in a blow? Your opinions would be appreciated.

mel

[nies]

I have used SS screws, either self tapping or  drill/tap machine tread in the mast or boom without any problems with either......when in doubt drill and tap.....easy in AL and makes you feel like a real rigger.........,Phil

[Bob23]

Big-mouth Bob23 here again:
   I've never had a drilled and tapped screw come loose. I guess if it was a concern, some Loc-tite would help ease a troubled mind. For me, rivets are out of the question, not to infer that all who use rivets are nuts. We do live in a free country, at least for now. Sorry. Hard to resist.
   Mel:
   If a fine thread screw is used, there are more threads in the thickness in the wall of the mast and/or boom. Just remember not to over-tighten. Cross threading is not much fun.
Bob23

[brackish]

I've also used either machine screws or through bolts exclusively for anything that I've added to the mast or boom.  However, the Dwyer site recommends SS pop rivets for most of the attachments.  With all their experience, must be able to carry the load reliably over time

23 boom section with accessories:  http://www.dwyermast.com/items.asp?cat1ID=30&cat1Name=Booms&familyID=5&familyName=DM-275+Boom

I think I would be comfortable with SS pop rivets for anything that is considered a "permanent" attachment

[Salty19]

Yes, the problem with pop rivets is they are difficult to remove (you have to drill them out).  I think they are fine on those attachment points where you do truly want it to be on for good OR where it's difficult or impossible to put a backing nut on it.

Note there are rivets used already on the mast and boom. Never heard of them failing?

A boomkicker?  I don't imagine a great deal of force is on the hardware here.  I could be wrong.  And if the rivet or tapped screw breaks loose...just repair it.  the boat is not going to fall apart. 

On the bom, I like the idea of rivets or tapped screws because you don't have a sharp protruding nut on the boom ready to put a dent in your forehead.   Stainless rivets are available.  For other fasteners, I use only SS small thread fasteners with SS washers and SS nuts. Fresh water or not...they will not rust.  However since the boomkicker has a hound on it which will also put a dent in your forehead...I would drill out a small recess for a nut in the hound (if it's thick enough) and through bolt it (with Permatex Anti-Seize). 

Remember to always put Anti-Seize on when two different metals are touching each other.  Otherwise galvanic corrosion will occur and they fasteners may have to be cut off (my father was a corrosion engineering chemist at one time that developed stuff to prevent this type of corrision).

Bmiller...something to try is to put a pair of vise grips on the stuck tap and twist it out.  If that doesn't work, build up some marinetex on the tap, let it dry into a square pattern and put a power drill on it with the chuck tightened, remove with drill on reverse.  If that doesn't work, heat it up with a butane torch and try the vice grips again.  Should come out.  I had a similar problem on another project and the second method worked well.  Tip:  Do not use Sears Craftsman taps.  they make very good consumer grade tools, but some of their specialty stuff is just not that good.

[kahpho]

Good points all. And thanks for the ideas.

mel

[bmiller]

What size fastener do you generally use?
mel

Most everything attached to the mast or boom is held in place with 10-24. I keep a 10-24 and a 1/4-20 tap with the correct sized bit taped together in the tools onboard, and a cordless drill. Plus plenty of various sized screws and bolts. I've made repairs in the middle of nowhere.

Salty, the tap sheared off perfectly flush. I thought about drilling the center then easy outing but that high carbon steel is a bitch to drill into. So it's a permanent reminder that anybody can screw up if you don't pay attention.