I'm considering preparing for a long distance triathlon, but I have some questions /concerns about the swim portion. Specifically, I'm concerned about drowning. I know I'm not able to swim 2 miles non-stop. I also know that I'm negatively bouyant, even in the ocean. So in order for me to attempt a 2 mile swim I have to be able to stop and rest at regular intervals. I seem to recall that years ago when a triathlon was broadcast on TV, the swimmers would tow a bouy. Is that allowed? If not, how can a swimmer stop swimming and rest for a few minutes before continuing? In the bike and run portion, it's easy enough to stop pedalling or running in order to rest.