…unless you have talked to the owner and received their approval to do so. This is a very big safety issue. When I started the rewire project on my boat I switched my boat breaker off and unplugged my boat. When I came back a few days later my boat was plugged in and the breaker was on. Fortunately, I had the power cord unplugged at both ends. However, this can kill someone if they think their boat is unplugged and the power is off when they are working on the electrical system in their boat. In addition, it could cause a fire if there are electrical issues on the boat.
Since we do not have a lockout/tagout program for our boats, a hard fast rule is to NEVER connect or reset power to a boat without checking with the owner. A good way to ensure a safe working environment is to remove your power cord completely and store it where it is not accessible to others. I have kept my cord available because I am using power for my tools.