IOMICA Forum

As has been pointed out here previously, the current IOM Class Rules do not provide a definition of permitted materials for rig fittings.

In the past I believed that this was not an issue and that the class simply assumed that rig fitting materials are unrestricted.

However, over the past weekend, I observed at a US regional race, a number of boats that had machined tungsten jib counter weights. As many of you know, tungsten is heavier than lead and is prohibited by many sailing classes.

I guess this brings the question of rig fitting materials back into focus. As I see it there are a number of things we can do:

1. Nothing. We can just allow things to continue as they are and simply agree among ourselves that rig fitting materials are unrestricted.

2. We can agree to modify the rules and specifically say that rig fitting materials are unrestricted.

3. We can come up with a list of permitted materials. For example, we could decide to not allow exotic materials and ban titanium, tungsten, spent uranium and/or carbon fiber.

4. We could make a general prohibition that bans any materials heavier than lead (tungsten, uranium etc.) anywhere in the IOM.

In all events, to the extent any changes to the rules are desired, I would suggest a class vote, first by the World Council members and then at the next opportunity by the entire class.

Anyway, all thoughts as to how to proceed are appreciated.

Tungsten is already allowed in another area within our rule (C7.3 (a)), why would you want to disallow it here?
I'm a bit confused on your stance here. In a previous discussion you were opposed to a proactive TC position. Has anyone requested an interpretation? If not, why would this instance be any different?

I don't have any real heartfelt reasons to change what we are doing but why not just state that the materials are free and then it is at least acknowledged and validates what we are letting happen anyway. If it is stated now then if we collectively decide something is not right there is a platform to go from.

Sometimes it is good to state the obvious.

Well I sat last night and read through the ERS and Class Rules. As Roy says there are no material restrictions on counterbalance weights. I have not seen the weights in question myself but since Tungsten is a denser material than lead the counterweights would then be smaller and so cause a small reduction in drag. Or maybe be the same size and with a shorter projection. Either way it really doesnt matter. Just as the modern lead has added antimony to make it harder and so more practical without comment, this seems to me to be a natural and harmless development. Intersting to discuss but no need for action.

C.7.3 ADDED WEIGHTS
(a) Weights of any material may be positioned in and/or on a mast spar below the lower point. Weights of density greater than 8.000 kg/m3 may be
positioned in and/or on a mast spar above the lower point.

Not sure about the wording of this section. Does it really mean that weight of any density is OK below the lower point while only weight less dense than lead (11.35 kg/cubic meter) can be used above the lower point? Or is this less about density than about positioning on/in the spar?

Bruce Andersen wrote:
Does it really mean that weight of any density is OK below the lower point while only weight less dense than lead (11.35 kg/cubic meter) can be used above the lower point? Or is this less about density than about positioning on/in the spar?

It's the other way around. It prevents someone from using a carbon spar inside and above the band as a "corrector weight".
Feel free to use anything denser than 8 kg/m3 above the band, but not less.

Maybe I'm the one who's density needs to be examined, but something doesn't seem right to me.

The rule in question says corrector weights placed above the lower measurement point must be of a density greater than 8 Kg/cubic meter.

That's about 17.6 lbs for a cube roughly 39" X 39" X 39"... right ?

That seems very light to me.

I'm not sure what the density of a carbon fiber/epoxy laminate is, but I would think it is denser than 8 Kg/cubic meter.

It seems to me that just about anything with a density greater than foam would satisfy the rule.

Lester, care to weigh in ?

Er, for 8.000 read 8,000 I think.

OK... I'll buy that.

And carbon spreaders - they are now appearing at events and people are asking if they are legal. I can't see that they are not since, as we have stated, materials are not even mentioned. I think it worth while clarifying the issue one way or another.

Roy Thompson
Rules and Measurements Officer ESP IOMNCA