I bought a pair of Howard Leight brand earmuffs that you can plug into an MP3 player for hearing protection + ability to listen to some bangers while you wrench on the mains.
Get a multi-tool, a sheath knife, and a flashlight with holster, keep 'em all on your belt always.
Love my X-tra Tuff insulated steel-toed boots, with an extra orthopedic insert. Standing on steel decks all day does a number on your feet. Redwing and Danner also make good boots.
Get some Grundens foulies, and some merino wool clothes to wear under them. You can find the latter cheap at most thrift stores. I also love my Grundens sea-bag, but you really only need a big backpack.
Never leave home without my Kindle.
I also keep a personal locator beacon on me. I’ve never had to use it, but if/when I do, it will be the best $250 I’ve ever spent.