Jose Salvador Alvarenga was fishing off the coast of Mexico in late 2012 when a powerful storm sent his boat adrift. Marshall Islanders found the battered vessel nearly 16 months later, stuck on a reef—with Alvarenga still alive inside. Rainwater and a diet of fish and turtle sustained him (or so he told the press). Curious how DIY savvy could stave off disaster, we asked Frances and Michael Howorth, authors of The Sea Survival Manual, for advice.
Shelter: Don't discard any clothing; multiple layers can keep you warm during cold nights. On hot days, drape or prop clothes overhead.
Water: Never drink seawater. If you have a raincoat, detach the hood and use it to catch and store rainwater. Plastic bags and rain boots also make excellent containers. Always rinse them with the first raindrops to wash away salt from sea spray.