In the Maldives we always carry SMBs and use them probably 90% of the time. Diving some outer reefs with strong current I normally deploy from depth as the current can move you pretty far from the reef if you ascend 'normally' ie. not swimming to stay on the reef. Theoretically
the boat will notice the bag and be able to track it as you drift.
Sometimes multiple groups are ascending at the same time and depending on where you are on the reef, currents here can be moving in quite different directions. This is where a good crew earn their keep.
My current SMB is yellow. It came in handy on some busy sites like South Ari Atoll's Maamigili (crowded whale shark area) as my boat knew it was me. Later when i worked as a videographer, the boat knew to pick me up first (to film guests exiting). In areas with technical divers present, yellow may be misunderstood, so I used a normal red/orange in Sharm el Sheikh.
You can practice SMB deployment in shallow water such as a swimming pool- in fact I recommend it. The videos posted spell it out pretty clearly, keeping the line free from you and be ready to let it go if it somehow birdnests. For this reason I prefer spools to reels, however I use a reel for measuring distances during AOW training. It is difficult to get a fully inflated SMB from a 15' stop. From deeper eg.35', it is a lot easier (Boyle's Law).
If guests here wish to dive unguided, they must demonstrate to us that they can deploy an SMB underwater. Again, the current can really move you if you drift during your safety stop. If you surface out in the ocean swell, you are extremely difficult to spot so the SMB
must be deployed while still in proximity to the reef.
As always with diving, the conditions and situation dictate what is the 'best' thing to do. I bless my stars that I don't have to deal with jetskis in my area.
