Interpretation 2004-IOM-3

[Chairman]

The ISAF-RSD has published interpretation 2004-IOM-3 on their Web site. In summary:

Q1. Is the bow bumper of a boat which meets the required 10 mm only at deck level and thinning towards the water line in accordance with IOM Class Rules?

A. Yes (please see the full text for detail).

Q2. Are the U-shaped nails driven into a wooden mast as attachments for the mainsail luff to the mast in accordance with IOM Class Rules?

A. No (please see the full text for detail).

[Jens]

Hi Lester,
this is Jens Amenda from Germany. I´m now "registered"...

At the moment Heinz Bohn and me discuss about the answer to Q2:
Is the difference in the answer only the point whether the U´s hold the mainsail directly to the mast or they hold the mainsail jackstay?
I´m thinking......:
If I use a carbon stick (inside the mainsail luff) as a mainsail jackstay, the mainsail luff has (6) openings and at this points there are U-shaped nails/wires (at the backside of the mast) which rounds only the jackstay (the jackstay is movable inside the U´s) - is this the correct way to to use a mainsail jackstay and the U-shaped nails as the fittings for it?

Bye
Jens

[Chairman]

Is the difference in the answer only the point whether the U´s hold the mainsail directly to the mast or they hold the mainsail jackstay?

Hi Jens

IMHUO, yes. I'm sure Charles will jump in here if my unofficial opinion is faulty. This is the text of the interpretation on Q2:

Class Rule F.3.3(b)(6) states that the mast spar ring and/or loop are optional fittings used to attach mainsail luff to the spar. Loop means a piece of non rigid material passed around the mast and carrying out the same function as a ring. These two items must be able to move freely. Class Rule F.3.3(b)(7) states that the mainsail jackstay fittings are optional mast fittings.

U-shaped nails driven into a mast to attach mainsail luff to the spar are not optional fittings as described by closed IOM Class Rules. U-shaped nails or staples are permitted if they are used to attach a jackstay.

If I use a carbon stick (inside the mainsail luff) as a mainsail jackstay ...

IMHUO, I am not sure that you can use a c/f jackstay, according to section F.5.

F.5 STANDING RIGGING
F.5.1 MATERIALS Except for terminations and the headsail boom swivel, the standing rigging shall be of steel and/or polymer.
F.5.2 CONSTRUCTION
(b) OPTIONAL (3) A mast spar jackstay less than 1 mm in diameter

... the mainsail luff has (6) openings and at this points there are U-shaped nails/wires (at the backside of the mast) which rounds only the jackstay (the jackstay is movable inside the U´s) - is this the correct way to to use a mainsail jackstay and the U-shaped nails as the fittings for it?

IMHUO, this seems fine according to the interpretation -- the U nails can hold a jackstay. Of course, the sailor has the problem of un-bending the sail if he wants, but that has nothing to do with the legality of how the jackstay is fastened to the mast...

[Jens]

Hi Lester,
thanks for Your answer.

IMHUO, I am not sure that you can use a c/f jackstay, according to section F.5.

I´m sure that there were a lot of discussions about the usage of a carbon stick at the mainsail luff... and surely an answer.... Where can I find it?

Some weeks ago it was the time to try a new sail material.... and the same problem as every time I try this (1 or 2 times/year) came up: How to make a good profiled sail and no WASTE?! I´m just no professional sailmaker... but I WANT TO DO IT BY MYSELF!!!
The carbon stick used by several sailors and Michael Scharmer´s idea with the U´s in combination would be the best way to attach the mainsail to the mast. The sail can´t move too far beside the mast, taking away all the fantastic shape you worked in the sail body. The sail would be easyer to trim, easy removable from the mast, if you take the stick out of the luff and no expensive construction to get tension to the jacstay would be necessary.... All you need is a drill machine, a pliers and a little bit of skill...

Now, if class rules say NO....that´s life...and I have to accept...

But sometimes I think that all the restrictions, especially in the fied of fittings, bring more problems than solutions, especially to those who try to build EFFECTIVE AND SIMPLE (+ unexpensive and by their own). Often an advantage of a construction is more than doubtful....
I don´t know weather I´m absolutely right - the first IOM rules said (a long time ago): `The way to attach the mainsail to the mast is free´...
Do we make all this really alright?

And what means "IMHUO"? I´m a stupid German...

Bye
Jens