Boom/mast connection question (Carbon Fiber)

[John Stevens]

A friend gave me a hollow carbon fiber mast, 2 inch diameter for my pram. I'm going to be attaching a wooden boom to it and would like to know the best method to attach it? I'm worried that screwing a gooseneck into the mast will rip out or damage the mast.

TIA,

John

[Dave R1]

John, what sort of rig are you intending to use? For a boom, you might want to put boom horns (like gaff jaws) on the boom and then use a downhaul to prevent it from riding up the mast. You could put a wooden collar at a point on the mast slightly below the boom's normal position which would support the boom when the sail is furled.

If you can get a copy of John Leather's The Gaff Rig Handbook second edition, there is a drawing on page 13 of this sort of set up.

It would be pretty easy to set up and knock down for trailering and you wouldn't have to put any holes in the mast.

Page 14 in the same book shows a catboat with the boom gooseneck attached to a 'crab', a separate fitting mounted on the deck just aft of the mast.

Another alternative would be to use a boomless spritsail. This would require a small thumb cleat mounted on the aft side of the mast about midway up from which a snotter is held. The opposite end of the snotter slips into a notch at the lower end of the sprit. You could possibly forego the thumb cleat by tying the snotter onto the mast with an icicle hitch. The icicle hitch is so named because it supposedly can hold on a tapered icicle and not slip even toward the tapered end.

The boomless aspect of the spritsail means you aren't going to get smacked in the head when you tack or gybe.

Izzat any help?

[capt jake]

If you are concerned about the fasteners pulling out; why not through bolt it to the mast? On the Weekendrs it works really well.

[John Stevens]

The sail is a sock type, slips over the 2" mast and is loose footed on the boom.

I've thought of both the bolt through the mast and horn type boom. Still not sure which way to go.

John

[Frank Hagan]

"Pinching" the mast with a through bolt might not be a good idea. I don't know carbon fiber that well, but I know with hollow wood masts, you can crack them with the two pressure points a through bolt gives.

A better idea is to fix something that would put the stresses of the boom around the circumfrence of the mast ... something along the lines of a cranse iron, or saddle. At the top of my hollow mast, I used chain link fence post bands ... which come heavily galvanized ... and painted them black:

You might get lucky and have the fence post bands for the 1 1/4" fence posts fit. You could fix the gooseneck assembly, similar to what the Weekender does, to the through bolt.

The other option is to see if you can insert a solid "plug" up in the mast where you are going to connect the boom. The solid plug is to prevent the "pinching" action of the through bolt. If the carbon fiber mast is not tapered, you might be able to insert a dowel of the appropriate diameter into the center. You can also use flat stock (1x2, for example), positioned lengthwise in the center of the mast so the throughbolt goes through the edge of the flat stock.

[John Stevens]

The fence post clamps might be a good route to take. I'll look into that more. I had thought of putting a dowel up there with the bolt also.

Thanks to all.

John