Yes, sort of...
phrf is a racing oriented value, so it takes into consideration a lot of other factors and reflects sort of an average of the totals. It really means that in a race between your two boats, the C&C has to give you 51 seconds for every NM the race course covers in a straight line from mark to mark and around obstructions. This might not reflect the difference in your boats when sailing one NM on a single tack on, say, a broad reach. For boats that have been around a while, it represents an averaging of their performances against a theoretical ideal value, in this case 0 (though there are boats with negative phrf numbers.) So, theoretically at least, it includes the considerations that in light air one boat might be faster against the other (relatively speaking) while in heavier air that boat doesn't do as well compared to the other. Included also are other factors - one boat might point higher, or tack faster, or be better downwind, etc, etc. All these factors come into play, so that in the end the handicap number gives you a fair chance of winning your share of races over a season, even though on some days you might be advantaged by conditions, and on others disadvantaged. And all this assumes a boat in very good shape, with good crew and skipper. If you have older sails, or a dirty bottom, or any of a number of things that degrade your performance you won't come close to sailing to your handicap. Likewise for a knowledgeable skipper compared to a newcomer to racing. So just because there are 51 seconds between your ratings, don't bet your house that, starting side by side, the C&C will be 51 seconds ahead after one NM. And if he is a better skipper, in light air the gap could be more like 5 minutes. If you catch the first shift, you might more than cover that 51 and show him your heels. But over a season, averaging up your times, all other factors being equal, he should average about 51 seconds per course NM faster than you.
