Anyhow, what this person is reading right now is a really, really big DC ground fault on thier boat that is entering the water around the boat. (The meter is set to the DC volts scale.) Yup, the boat is dumping almost 11 volts DC into the water around the boat. It has not blown a fuse or circuit breaker because there must not be enough amperage flowing to do so. Not an uncommon thing to occur.