Well we are in semi tropic water with many reefs to deal with, but they don't pose much of a hazard normallly unless you're sailing into the sun and get blinded!
We only go around the island if the wind is a favourable direction, meaning we can reach on the longest legs. On the leeward side we have to maintain one to one and a half miles offshore so not to be affected by the wind shadow.
Because of the risk, organising the trip is important, with mobile phones this improves things somewhat. Overall the rounding can be done in just over 2 hours, to break 2 hours would be the aim.
I guess the difficulty is knowing that such long legs are reaching, is working out whether a slalom board in the 120l range with a 8.4 can make up the time. I know there is for sure a speed advantage, but how much would be needed. It's something for us to try and figure as we know the course more specifically. But it's nice to hear the same problem exists for others!!