Your selection of the right gear, and the right amount of gear, will be with you throughout the trip.
Either it will be a useful item, or just something that takes up valuable space and weight, and which you may stumble over.

Essential Boat Gear and Spares

There are dozens of gear checklists to be found on the internet and in cruising books. These are a mixture of my experience and some of the aforementioned lists.

For all boats

For Boats with engines & 12 volt batteries

For Sailboats

First Aid & Comforts Afloat

General Comforts & Problem Prevention

First Aid Links:
Several References to First Aid Afloat

Gear Links:
Calculator for U.S. Coast Guard Minimum Equipment Requirements
Gear Recommendations Calculator
Power Boating Checklist from Canada
Sailboat Cruise Equipment List