Having taken thousands of guests sailing and snorkeling I am absolutely convinced that a flotation device saved a lot of people from having problems. Even the [USCG Not Approved] ski belt type will keep someone floating and able to rest and be rescued if necessary. Having someone on deck watching is another essential part of a safe program. Not swimming,snorkeling alone should be a rule especially for a person not having a flotation device . Even a simple floating noodle can be carried by one or more of the group and may be the thing that saves a life that day.
I am very sorry to hear of another life lost here on a boat trip, it happens way too often here and is a terrible thing in every case. That is the major worry and serious concern for every Captain everywhere, one that haunts you forever if it happens on your watch and if Negligence is proven evident probably a career ending tragedy.
VISAR is an incredible group of responders and deserve the financial support of any owner/charterer who sails the BVI.