Surface marker buoys

One of the skills learnt in technical diver courses was deploying a lift bag during decompression; this skill was learned in case of a missed ascent line. 

The purpose was twofold, it allowed the vessel to follow decompressing divers from the surface and gave a reference for a blue water ascent for long hangs. Needless to say, the ascent phase is critical to a stable and safe off-gassing schedule during decompression preventing the growth of bubble nuclei.

I love diving South East Asia and have noticed every dive guide in the region is equipped with a finger reel and surface marker buoy, this has been a great innovation from technical diving seeping through to mainstream diving procedures.

On many occasions, the boat does not moor on coral reefs with divers following the divers conducting their safety stop in current. Instead of a lift bag, the safety sausage is now used with higher surface visibility than a lift bag.