One final point to Jakes description

You want to look at the column Elapsed time to win (or ETW in sailwave) as opposed to the corrected time.

Corrected time is that magical place where all boats of different sizes are racing in virtual space...

So...
A time on time Handicap must be converted back to real time on your boat to make any sense to you.

So the ETW is the actual time in seconds that you would need to save on the race course to win that particular race... This time is directly related to... Slow tacks... time spent going the wrong way...lousy starts, flubbed mark roundings....
and all other aspects of racing other then boat speed...

Most people who complain about ratings change their tune when they count up the time lost in mistakes they know they made out there compared to first place boat.