How much Warm up for a Half Ironman?

Besides just making sure the bike works and getting use to the water temp is it a good idea to do an extended warm up (30 mins) before the race?

Dave in VA

Also, will someone give me a recommendation for a sunscreen lotion that I can but on before the race (under my wetsuit) that will stay on for 4+ hours of intense racing and sweating.

A good 10:00 run will help loosen yourself up and warm up for some stretching as well get the pipes going for the port a potty visit. a good 10:00 swim warmup is good loosen up the shoulders and arms. Have fun and hope this helps!