Just bought a couple of these great MOB devices primarily designed for divers and so cheaper than sailing equivalents. The Nautilus Life Line is a marine rescue GPS for divers so it is waterproof to 150 metres, very rugged, very compact and buoyant. It can be programmed with an App so that it remembers your boat's MMSI.
When triggered it sets off a strobe, acquires a gps position, sends a DSC emergency message to your ship's VHF (thus alerting your crew) and broadcasts an AIS signal that can be received by any AIS equipped vessel within VHF range. All this for £145 on Amazon. See www.nautiluslifeline.com for details. Takes camera lithium batteries (CR123) with a 9 year shelf life. Hope never to use it.
edited by simoncurrin on 6/28/2017