ISMA News - Association Suisse 6mJI

ISMA News International 6mJI Association Bulletin 1/2004
Commentary from Ian Howlett to the questions of exotic material
This paper has been presented at the AGM 2003 in Saint-Tropez and should be handed over to the technical committee
for eventual changes or clarifying notes in the 6mJI rules. We present the paper to all our readers:
Introduction
Rule 33 „ Exotic materials etc „ was inherited from the Twelve Metre Class from the days when such was the America’s
Cup Class . In particular in 1970 the 12 Meters had been experimenting with Beryllium clad topmasts that in the memorable
words of Rod Macalpine Downie „ turned deciduous „ . Spreaders were also made using Boron ....
Today materiials such as Carbon Fibre composites could not be regarded as exotic ( used in Tennis Rackets , Golf Clubs
, masts in cruising boats etc etc ) but such would add considerably to the cost of certain items should such be permitted
. By way of illustration the Rig for an Int 5.5m Class Yacht ( which is considerably smaller and lighter ) would cost some
Euro 29K .
Interestingly in 1980 prior to the America’s Cup I obtained written permission from the IYRU to make the mast and the
rigging from Carbon Fibre for Lionheart , but resources did not permit the construction of such - though we did build a
carbon boom and some battens .
I would suggest that the current Rule 33 be eliminated and that we clarify the situation by identifying the materials which
we want to be allowable for the items in question. These interpretations may then be modified in the light of experience
or changing circumstances .
I would suggest that we „ grandfather „ any masts or other spars that that do not conform to the new proposals - though
I am unaware of any such !
Regarding the Spinnaker Pole my researches provided the information that by spending an extra Euro 200 on a carbon
pole 2kg of weight would be saved ......
We already have a weight control ( 12.5Kgs ) on the rudder and the use of composites is the cost effective solution for the
construction of the same .
I propose ......
Old Rule 33 to be deleted in its entirety .
New Rule 33 .. .
The Mast shall be constructed of
1.Wood of any species
2. Normal commercially available aluminium alloys ( ie 5000 or 6000 series ) . Paints , varnishes and fillers for the same
are acceptable and may be used to bring an undersized tube up to Rule dimensions .
‚Solid ‚ shall be interpreted as as of one type of materiial only of approximately constant density .
Spreaders shall be made of timber , aluminium alloy or stainless steel .
The Boom shall be constructed of
1.Wood of any species
2. Normal commercially available aluminium alloys ( ie 5000 or 6000 series ) .
The Spinnaker Pole - may be of any normally available commercial material .
Reinforcements to repair or strenghthen an existing spar that conformed to the Rule may be of any normally commercially
available material and the same shall apply to the hull and deck .
NB ( the purpose of this clause is to allow cost effective repairs/stiffenings to a wooden or metal mast or boom )
Rigging
Shrouds and Forestay shall be of normal commercially available Stainless Steel wire or rods made of materials such as
Nitronic 50 .
Rudder
Any normal commercially available materials may be used for the construction of the rudder ( only constraint is the
minimum weight )
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