Diving includes snorkelling. Snorkellers who rarely leave the surface still expose themselves to many hazards, including drowning (see Chapter 61). There are few well-documented series of these incidents. Walker described 90 snorkelling deaths between 1972 and 1987, although many had no forensic assessment1. Edmonds and Walker described 60 such deaths between 1987 and 1996, all of which had coroners’ inquiries and/or autopsy investigations2. Lippmann and Pearn described a further 130 cases, up until 20063.
Surface drownings caused about 25 to 45 per cent of the snorkellers’ deaths. Drowning followed hypoxia from breath-hold diving, usually after hyperventilation, in 15 to 20 per cent (see Chapters 16 and 61 for these conditions).
Surface drownings tended to occur in an older but wider range age group than the hypoxic drownings, but at a younger age than those who die of the other major cause, cardiac disease. These snorkellers were often aquatically inexperienced, less fit tourists who engaged in commercial reef-snorkelling trips or solo swimming. Frequently, they had medical disorders that made them more vulnerable, such as epilepsy, respiratory diseases such as asthma, salt water aspiration and vomiting. Adverse environmental factors, such as currents and choppy surface conditions, were contributors in 15 per cent. The absence of fins in 40 per cent made coping with aquatic conditions more difficult. Overall, the physical unfitness and aquatic inexperience that led to panic and aspiration dominated the situation.