Wire nuts are commonly seen on do-it-yourself projects. A marine technician would normally choose to use a butt connector, or an even better choice, a heat-shrink connection.
The American Boat & Yacht Council (ABYC) electrical standard simply states:
E-188.8.131.52 Twist on conductors, i.e., wire nuts, shall not be used.
Minimizing risk on the water is the goal and in this situation, it’s an easy fix.