IRC Rules currently make no reference to permitted materials for hull appendages (keels, rudders, daggerboards etc). In response to the manufacture of some keel bulbs from tungsten, IRC Rule 24, Keel, Centreboard and Rudder, in IRC Rules 2005 and 2006, is amended with effect from 1 January 2006 by the addition of:
|24.5||In the construction of hull appendages, no material with specific gravity greater than 11.3 is permitted.|
|24.6||Boats including material in their hull appendages with specific gravity greater than 11.3, and with Age Date of 2005 or earlier, and holding a valid IRC certificate on 31st December 2005 are exempt from rule 24.5. Any such boat replacing material of specific gravity greater than 11.3 with material of specific gravity less than 11.3 shall comply with Rule 24.5 and will not subsequently be eligible for exemption from compliance with IRC Rule 24.5|
In addition to the above, owners are advised that the rating of boats including materials with specific gravity greater than 11.3 will be reviewed.
The IRC Rule is managed by the RORC Rating Office and the UNCL.