6.1 One rudder and one centreboard only shall be used at anyone time. At all times when sailing, both sides of the centreboard and rudder shall have similar profiles. Leeboards, daggerboards, hydrofoils, trim tabs, fences and similar devices are prohibited.
6.2 The centreboard shall fit within the centreboard case not extending below the bottom of the hull when fully raised. The trailing edge may project above the centreboard case top when in the raised or partly raised position. No part of the leading edge which is more than 300mm from the tip and is capable of protruding below the hull shall be capable of being raised more than 200mm above the bottom of the hull. No part of the centreboard shall be capable of protruding more than 1450mm below the hull.
6.3 The rudder shall be hung at the transom and no part of the rudder assembly shall pass through the skin of the hull. The tiller may be shipped through a port in the transom or over the top.