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Holes in booms

Posted: 06 Mar 2009, 13:18
by Gilbert Louis
Hi, I'm not too sure on this one hence why I'm looking for advice on the rules before I start drilling my booms.

some of my booms are too heavy and I'm looking to drill holes in them to reduce the weight (I can afford to loose weight as I'm slightly over anyway on the overall boat weight.) So if we leave the weight aside my question is more on wether or not we're allowed to drill holes on booms.

My plans then once the holes are drilled is to cover them with a light adhesive. Anyviews ??? is this within the rules ?

thank you for your views

Posted: 06 Mar 2009, 14:07
by RoyL
Mixed answer here. You can drill holes in booms to attach fittings, lines, etc. You can't drill holes in booms to lighten weight. So for example, a boom with inch long cut out holes would not be legal, a boom with three or four small holes to attach the sheet line would be fine. Sounds like what you are doing is not legal.

Posted: 06 Mar 2009, 14:53
by Gilbert Louis
Thank you for your response though that was my initial understanding as well - I can't find anything in the rules that would stop drilling holes in booms to lighten it in section F4 and since what is not in the rules is allowed !!!

I haven't drilled them yet as I'd like a definite answer so to avoid issues later on at international events.

Posted: 06 Mar 2009, 16:39
by Dick Carver
The spar section shall be constant......

It was explained to me that the word "constant" in F.4.2 means no lightning holes.

Posted: 06 Mar 2009, 17:28
by Don Case
This is where simple rules fail. All my adjustments on my boom result in an almost continuous row of holes. If I was to make the holes 1/8" in diameter it would lighten the boom quite a bit and apparently be legal. I guess we would have to define the maximum size of an adjustment hole. As near as I can see F.4.2. makes adjustment holes illegal unless there is another rule somewhere that allows them.

Posted: 06 Mar 2009, 18:33
by Andy Stevenson
Hi Don
Don wrote:F.4.2. makes adjustment holes illegal unless there is another rule somewhere that allows them.
I think F.4.2(b) allows for adjustment holes:
CR F.4.2(b) wrote:openings for fittings and rigging.

Posted: 06 Mar 2009, 19:20
by Dick Carver
I think the rules work fine here.
It's another one of those areas where there are tradeoffs.
If you go to big adjustment holes to lose boom weight, you're going to have coarser adjustment. You could overcome that with transmitter adjustment, but why bother. In my opinion, finer adjustment (smaller holes) means better control.
You're also going to have a big clunky sheet hook. That will add some weight back.
The argument seems to be that lighter booms will rotate better in real light air.
From my experience, getting the booms to sheet out in light air is much more a function of things like back stay tension, jib counter balance position, cunningham tension and having as little friction as possible in the gooseneck.
As long as the booms aren't heavy, stiffness is more important than weight.

Posted: 06 Mar 2009, 21:22
by valpro
Two points to bear in mind here. These are closed class rules so unless something is specifically permitted, it is not allowed and rule F.4.2 does not include 'lightening holes'. Secondly you mention covering these holes with adhesive film and that is not an allowed material under F.4.1. Now you can argue that these holes are for adjustment but you if you use them for that, firstly the attachment will have to be proportionately large (and therefore heavy) and secondly you would not be able to close them off as you seem to imply in your mention of a film.

Posted: 07 Mar 2009, 00:49
by Gilbert Louis
these are good answers but it seems I've brought up another tricky subject as responses seems to vary. As I said in one of my earlier post my understanding was that lightening holes were not allowed (don't see really why they wouldn't mind you) but as Valpro confirmed too this is not specified in the rules and therefore should be allowed. Though the film I intend of using is an adhesive and therefore permitted in F4.1.b.

I don't have any other purpose in this action of drilling holes then to lightened them as they're simply too heavy to my taste. The aim is to bring them to a similar weight as the GB profile ones. I'm not trying to gain a few grammes to make them even lighter. The allow thickness is bigger making them way too stiff and heavier that's all... if it is decided that lightening holes are not allowed then I simply won't use them again but for now I do. They are of constant shape, size and diameter so F4.2 is not broken...

Posted: 07 Mar 2009, 01:26
by RoyL
Nice try, but lightening holes of constant shape, diameter etc. do not satisfy the rules. Also an adhesive film to cover a hole is not the same thing as an adhesive used in building a boat or rig.

This one is really pretty clear. If you have lightening holes in your booms they are illegal and the booms should be replaced.

Posted: 07 Mar 2009, 07:45
by Bruce Andersen
It seems to me that the answers don't vary - holes cut to lighten the boom are illegal - holes used for sheet adjustments are. I suggest that if you use the boom keep a close eye on who sees it and be prepared for a challenge. This has been tried in the past and didn't work then either.

Posted: 07 Mar 2009, 11:13
by Lester
Gilbert Louis wrote:as Valpro confirmed too this is not specified in the rules and therefore should be allowed
Hi Gilbert

You said something similar earlier and I thought that you had simply forgotten to include a 'not'. What Val said is that the IOM class rules are closed class rules, and that anything not explicitly permitted is therefore *prohibited* and is *not* allowed.

Posted: 09 Mar 2009, 01:05
by Gilbert Louis
My mistake I mis-read Valpro's post.

thank to all for your responses - so I won't drill holes in my booms.

But out of curiosity can I ask why it wouldn't be allowed ? what would be the reason(s) behind, I don't see what advantage one would gain by having lightening holes apart from gaining weight on the boom if one believe they're too heavy particularely since the boat has minimum weight ? i remember in the 80s when the curtain rail was a favorite for booms quite a lot of skippers had lightening holes.

Posted: 09 Mar 2009, 08:22
by Lester
Hi Gilbert

I don't think the class has anything personal against holes in booms (smile). It is a class philosophy thing which one buys into (or not, as the case may be). The idea is that the rig is strictly controlled, making it effectively a one-design rig. The hull is less strictly controlled, such that there is freedom in hull form. And both parts of a boat (with the unfortunate exception of the fin!) should not place any premium upon building skill or 'exotic' materials...

Posted: 09 Mar 2009, 23:04
by valpro
Gilbert, I think it was in the original class rules and remains there. Rules evolve becuse people challenge the things they allow or forbid. The way to go is, if you feel strongly enough, to make a submission for a rule change and let the democratic processes of the class decide whether it is what the majority want or not