If you operate offshore, you should seriously consider carrying additional equipment beyond the minimum federal requirements. In cold waters, an immersion suit should be carried for everyone on board. Cellular phones coverage is available in many coastal areas.
Geostationary satellites make detection almost immediate.
Otherwise, make sure it is readily accessible. Registration is mandatory, improves response and reduces false alarms. An inflatable life raft can provide a survival platform for an extended period of time. Make sure the life raft is large enough for everyone on board when the boat operates offshore. It should have the appropriate emergency equipment pack, and should be professionally serviced periodically, according to the manufacturer's instructions.