There are no standard masthead spinnaker dimensions for PHRF nor are there dimensions adopted by the class. I discussed this with Carl Schumacher and we talked about the desirability of proposing and adopting masthead spinnaker specs by the Express 27 Class, but we didn't get around to it before his untimely death. Here are the dimensions adopted several years ago by the Detroit fleet:

Maximum luff length: 32.3 feet (class spkr luff=28.58 ft)

Maximum girth: 17.75 ft (class girth: 17.75)

The sail area is increased 56 sq ft or 13% with a masthead spinnaker over a class spinnaker. The calculations are as follows according to our local sailmaker:

28.58 ft x 17.75 ft x .85 = 431 sq. ft for class spinnaker

32.3 ft x 17.75 ft x .85 = 487 sq ft for masthead spinnaker

Our fleet uses the masthead spinnaker only for class events and we have not obtained a PHRF rating for the boat sailed with it. We have been told informally that we would take a hit of minus six seconds per mile with the masthead spinnaker from our 138 rating. That's in line with what Carl Schumacher told us to expect. He said "Try for three seconds, but you may get hit for six."

One other comment for anyone who does any main and jib racing. Our Detroit PHRF rating includes a six second one design spinnaker pole penalty from our "normal" PHRF rating of 144 which assumes a J length pole. For some time those of us who race in a main and jib series have used our regular 138 PHRF rating, but we have decided to declare 144 this year on the theory of why should we pay a 6 sec spinnaker pole penalty when we don't use spinnakers?

Winds on Lake St Clair are highly variable but are said to average 8-9 knots.

And because of the light winds on Lake St Clair when we went to masthead spinnakers our sailmaker-adviser suggested we consider going to a wider spinnaker and longer pole which would work fine, especially for windward-leeward courses. The class debated this and decided they didn't want to spend the money for longer poles and have to carry two poles, one for the class spinnaker and one for the masthead kite. That's why we kept the girth the same as for the "small" class spinnaker.

Finally, I find Ed Chung's experience puzzling. Seems to me he took a big PHRF hit for a small increase in sail area. But a PHRF committee is liable to do most anything!