well i use crimps and solder but i am weird. i use solder for big wires, as i dont have big crimpers. what i do heat the ring and fill it with solder, then i slightly tin the wire, just enough to get some flux on the wire, then i dip the wire into the hot solder and as soon as i see it penetrate the wire i take away the heat. then i use adhesive lined heat shrink to seal.
edit i have done big connections like this for 10 years, granted never on boats till a year or so ago. i have never had one fail, including on some pretty serious off road trucks that get plenty of vibration.
for small wire i use standard
anchor crimps, not heat shrink ones. then i fill the ends of the crimps with liquid electric tape, let it dry, then apply another coat until i cant see the crimp anymore. i also coat the end of the sheath with the liquid tape to stop it from getting any moisture up inside the sheath