A three-year, $3m study has important implications for seafarer wellbeing and ship safety. Project Martha incorporated data from seafarers of two European shipmanagers and two Chinese state-run companies that operate bulkers and tankers.

The project — sponsored by the TK Foundation and overseen by an international group of leading maritime researchers — asked the seafarers to fill out questionnaires, complete daily diaries and wear activity-monitoring Actiwatches for two weeks at the beginning and two weeks at the end of their contracts.