Seawind One Design Rules Clarifications

by Mike Eades, Seawind Class Secretary

February 19, 2014

The introduction of the new Readyset version SeaWind which has a steel bulb (larger than the old lead bulb but similar in weight) raised the question as to whether the new version SeaWind should be class legal. After initial review and sea trials (see product review) the Class Directors and I have agreed to introduce the following Rule Clarification as an interim measure. Final Rule change will be proposed in the next ballot at the end of 2014 by which time we should have accumulated enough experience with the new bulb to make a definitive decision.


This Rule shall be interpreted to include the steel bulb supplied as part of the SeaWind Readyset version as supplied by the manufacturer.

Rule 3A.1 Battery Box

A clarification was sought as to whether or not modification of the sides or ends of the battery box to accommodate a battery was permitted.

Rule 3A.1 is to be interpreted that the only permitted modification to the battery box, Part C5, is the addition of drain holes as specified in the Rule.

Rule 8 Spars

8.2 All mast and boom fittings, with the exception of cleats, bowsies and the vang rod, must be used and shall be located in the position defined in the kit instructions. ….

A few issues have arisen with loose or weak mast joiners used to secure the upper and lower mast sections. A note summarizing these issues and permitted modifications can be accessed (here)

Rule 10 Running Rigging

10.2 Methods and fittings used to attach and adjust the length of running rigging are optional provided they exert control in the manner that the kit design intends, with the exception of the clew outhaul for both jib and main which system may also include a downhaul or inhaul line.

A Rule Interpretation was requested as to the legality of a modification in which tension was maintained on the main sheet control line leading from the sail winch arm by addition of an elastic cord attached to the knot joining the main and jib sheets and attached to the jib pivot chain plate.

After an extensive consultation with the Class Officers, I interpret Rule 10.2 to disallow such a modification. In the kit design the only forces applied to the jib and main sheet control lines are the force applied by the sail winch arm and the opposing force applied by wind action on the sails.

Addition of an active tensioning force pulling the main sheet line through the deck pulley and above the deck is a departure from kit design intention and, in the opinion of several, could result in a performance benefit in light air by reducing the wind force required to begin to move the sails outward.

Rule 10.2 Interpretation 2

A skipper asked if an alternative outhaul arrangement would be permitted. The diagram below illustrates a conventional outhaul arrangement and his proposed alternative.

After discussion among the SeaWind Class Officers it has been agreed that the proposed alternative arrangement, although probably providing little if any advantage, is not permitted.

The outhaul arrangement shown in the kit instructions (a single line running from the sail clew through the hole in the plastic end pieces, Part #A4 for the main and Part # A5 for the jib and secured to the boom forward) was soon found to be deficient, especially for the jib where slackening of the outhaul simply resulted in lowering the jib boom providing no impact on sail shape. In the 2005 Class ballot a new Rule 10.2 was adopted which permitted addition of an inhaul line from the clew running forward and secured to the boom. A variety of methods of accomplishing this have been illustrated on Class web sites all of which maintain the outhaul line running direct from the sail clew (or a hook attached to the clew for ease of assembly) through the hole in the end piece as shown in the kit instructions.

The proposed arrangement which requires a new hole in the plastic end piece to which the outhaul line from the clew is secured is judged to be outside the scope of modification permitted under Rule 10.2.