I received the following reply to my inquiry to the RORC:

"We rated one Express 27 back in 2001, her rating was 0.933. Bear in mind that this was just one boat (not necessarily standard) and that the ratings will have altered slightly in the last 3-4 years.

"I am attaching a list of ratings (2004) for some well known designs, I hope this helps."

Here are some of the ratings from the RORC list:

Laser 28-.915;

Contessa 33-.935;

Dehler 34-.940;

J27-.940;

J29-.945;

J80-.970;

J105-1.02;

Mumm 30-1.09

Anybody know how these ratings translate into seconds per mile? Or how they can be equated to PHRF ratings?

I would be inclined to take issue with the relationship between the E27 rating and the Laser 28 rating. My impression is that the two boats are pretty close in performance in typical medium air conditions.