• A Marine GPS navigation system
• A 406 MHz EPIRB (make sure you register it after purchase, or rescuers may be delayed in reaching you!)
• A Coast Guard-approved life jacket (because they float, you don’t…)
• A handheld VHF-FM radio
• A Boating Safety Course (boater education saves lives — it’s a fact)
• Vessel Safety Check (VSC)  from the Coast Guard Auxiliary (it’s free!)
• A Coast Guard approved fire extinguisher
• A first aid kit in a watertight container
• A seamanship book
• Nautical charts for the areas your favorite mariner frequents
• A signaling kit
• A life raft with a survival kit

The full CG gift post is here.