Let’s face the facts! The most dangerous thing in the ocean is man-made. It’s the propeller on the dive boat you’re riding on or the propeller on the passing speedboat or yacht. Divers Beware!
What can you do?
First, always have an understanding of the configuration of the boat you are diving from. Is it an outboard boat with propeller(s) at the stern? Is it an inboard boat with propellers under the aft part of the hull? Does the boat have waterjet propulsion (with no exposed propeller(s)).
Second, listen attentively to any crew instructions. Ask questions if anything is unclear. How and when will you enter the water from the dive boat? Will it be moving or stationary? Will the propeller(s) be moving or stationary?
Third, what’s the re-boarding procedure when the dive is finished? How are you to approach the boat? How will the boat approach you? What signals or other communication should you initiate or anticipate from the helmsman or mate? Will the engine(s) be running are shut down when you re-board the vessel?
Fourth, when you surface after the dive, be as conspicuous as possible. You may blow a whistle to announce your presence to the dive boat crew. Watch and listen for oncoming vessels with operators that may not be aware of your presence. It may be wise to wave your dive flag or dive sausage side to side to make it more conspicuous to an oncoming vessel. You may even consider practicing rapid re-submersion skills. How quickly can you re-submerse from the surface to 4 or 5 feet below the surface in response to an oncoming vessel? Good luck with that!
Watch Those Props!