Les,

The diagonal measurement you refer to does not accurately indicate toe out or toe in of the hulls. You can sketch out a couple of examples of hulls radically toed out and toed in and see that the diagonal measurements can be exactly equal from one side of the boat to the other.

A better measurement of toe out/toe in is the distance between the bows compared to the distance betweeen the center of the transoms. On a boat like the Hobie 18 which does not have canted hulls this should set the hulls paralell in the water.

For boats with canted hulls, setting toe out/toe in is more difficult, but not impossible. One technique I recently observed was to establish marks at the center of the bow and transoms at the estimated water line of the boat with crew weight distributed for light air sailing (when toe out/in creates the biggest performance problem). Alignment was then adjusted until the distance between these marks was equal at the front and back of the boat.

As the hulls were canted 7 degrees, had a fair amount of rocker and the carbon beams were being bonded to the hulls, this was not a simple thing (they used an adjustable jig that held everything steady.

The bonding technique in Jake's excellent blog works well, and really tightens up a Hobie 18. This, together with improvements in the steering department such as fitting the one piece gudgeons can transform the feel of the boat.

Chris.