Welcome to the forum.
Assuming boat doesn't currently have shore power.
If correct, then addition / installation of shore power is not trivial task.
The shore power must / should be installed per the ABYC standard. There are many details specified that appear trivial, but all exist to ensure proper safety.
The ABYC standards are not free. Old versions exist on the Interlink showing the requirements from years ago and are a good starting point.
There are also web pages gleaned from the ABYC standards showing requirements.
There are also books available showing how to add shore power.
Short answer is I am 100% comfortable that I could properly complete that task with proper research and would speculate that I am in the minority of those possessing sufficient skills, experience, patience and tools.
If the boat is on the hard, then will a 12AWG extension cord to a GCFI receptacle provide an acceptable solution?
