Two quotes from Google articles below. I personally use crimp connectors, the same kind that we use on helicopters for work, but if you want to solder go for it. I personally feel it's easier to crimp than solder. The type of boats we have don't fall under the ABYC rules, they are not big enough.
"According to ABYC, all connections between connector and wire need to be mechanical crimped. Basically, you need to crimp the connector onto the wire. It does not hurt to solder the connector as well, but it isn't necessary."
"If you’re still wondering if soldering is better, remember that American Boat & Yacht Council Standards exclude solder as the sole means of electrical connection for wire terminations."