My boom (the part attached to the mast) moves up as I'm surfing.
Sometimes it moves down also, I guess it depends on what mood it is in...
What's a good way to prevent this?
When I rig my sail I already try to make sure the boomclamp is at it's tightest setting around the mast but still it slips up. I also tried another rope but no change. I guess maybe the boom rope grip is worn? Have to check that out next time... The mast is kinda small also compared to the boomclamp, but it's not one of those thin barbecue stick masts, just regular thickness, maybe a bit thinner.
Anyway, I'm looking for a way to fix this now cause it's annoying to have to re-adjust my boom all the time...
Is this a clamp on boom - like you move a big lever to tighten it ........... OR is its an old tie on boom where you loop rope around the mast a couple of times and there is no pivoting lever kinda thing on the front end?
What brand of boom?
I'm very cautious of overtightening the boom clamp onto the mast and use a thin (1mm thk) rubber sheet on the inside of the clamp. Only need minimal boom clamp tension and it doesn't move an inch. Since I got an RDM mast I've found the rubberised shims to be perfect for minimising (eliminating) boom slippage unlike the hard plastic shim that is generally supplied by manufacturer (just like the one in your photo below). The Severne shims are brilliant too.
It's a clamp on boom, this kind:
I think it's a neilpride but never really checked so not sure, it has been used a lot though, bought it from a windsurfing center.
Maybe the only problem with this option is excessive friction when feeding mast up luff tube.
JanPaul if it is *exactly* that kind - with a rubber insert in the front (the white bit in the pic) is the insert missing? On many booms they have one, it is just a simple press fit and can disappear.
On every clamp on boom I have used in the last few years, I have had no slippage problems and I am heavy and sail small boards so tend to hang a lot more weight down that u will.
So
(1) rubber bit missing?
(2) is the cleat slipping?
If neither of those two, then have an experienced person have a look as the right amount of tightness as you swing the lever over is a 'feel thing' that really can't be described and I'd hate you to crush your mast
Maybe the only problem with this option is excessive friction when feeding mast up luff tube.
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I think maybe the cleat is slipping though, I will have a good look at that next time I'm out.
Not sure what I can do about that though, maybe only new boom?
If the cleat is corroded and not gripping you may be able to sharpen it up by scrubbing the corrosion off with a wire brush, and/ or filing the teeth a bit to sharpen them up. Access may be difficult. If that is too tricky tie a knot adjacent to the cleat after clamping the boom on. The knot will stop the rope slipping.
Agreed^^^^
But may not be a stuffed cleat, if you thread rope through the cleat and then do it up, it will slip. It needs a bit of help to grab
The rope needs to be pulled down a bit into the vee and held there as you close the lever bit. You only do that the first time though. Hard to explain. Hmm....
so you put the boom on with lever open,
pull the rope thru the cleat until it is snug - not tight - snug.
Then hold the rope down into the cleat like wrapping it around the vee a bit
Then close the lever part and you can see the rope get pulled down hard into the vee of the cleat. Like really jammed in there
Then if that is the correct tightness on the mast and no slippage, for subsequent use you never touch the rope.
If it is a new boom, I will adjust that rope in the cleat and "do up - undo - adjust" maybe 5x or more to get it right.
So is the rope just loose in the cleat?
I ended up using a plastic mast thickener thingy (wraps/clicks around my mast), I don't know what it's called, they gave it to me at the surfing school when I described the problem and the boom's steady as a rock now.
