The Watertribe events require the ability to reduce sail. Some multihull teams have come up with a halyard extension that they would shackle to the head of the sail and connect that to the existing halyard ring. The sail would be rehoisted and the ring hooked like normal. The sail has a series of grommets matching that height difference so the sail can be lashed to the boom...and a large eye at the clew for the mainsheet attachement.

This does, however, require that the sail be completely lowered in order to attach the halyard extension.