Second row sucks no matter the fleet size. If it happens the key is to suck it up and start looking for an escape quickly (while still going as fast as possible). Taking transoms early in order to get to relatively clear lane is usually worth it in the long run.
I'd agree with Jeff here.. you can definitely recover from a second row start in most F18 fleets. Taking transoms early, getting out on your own and going fast is key. The first day in the gulf in Sarasota Dalton and I had a rough time starting and did this almost every race and made it to the windward mark in the top 20 most of them. Same thing at Catacup and worlds in Long Beach several times. An F18 is usually a lot faster on it's own than battling with other boats. Might be tougher in Nacra 17's though where it would be a lot harder to have a boat speed advantage with the talent there.
I'll third Jeff and Todd here. This is extremely evident even in a small fleet. For example, Mike and Tripp punch out into clean air early every time and have great starts. 2 boat 1 boat length behind them on the line in dirty air and you are 5 boat lengths behind in about 10 seconds. Once you break out into clean air you can start sailing at the same VMG as the lead boats and stop the bleed.