Freshwater is MUCH WORSE for
electric shock drowning that
salt water.
Your body will conduct the current BETTER that the surrounding fresh water, so currents will preferentially want to flow through you in fresh water. Current leaking into
salt water is not as dangerous since it has an easier time to flow back to source through the
salt water. All those fresh water marinas should have GFCI on the
shore power lines or ELCI breakers at minimum on the dock! IMO. Having it on the
DOCK protects people from leaky
shore power cords. If you just have ELCI or GFCI on the
boat, the shore
power cords not protected. I have seen shore
power cords in the water and leaking current cause they are damaged gotten pinched when boat hits dock and cord in the way, etc...
A damaged cord happened on my boat and the shore power copper wire was eaten up about 2 feet.
Insulation looked reasonably ok. This happened in
salt water. If there had been an ELCI breaker on the shore power source, then my wire would not have been a hazard. Nobody got hurt, I just happened to notice one day when the boat had
lost power.
All your wiring can be in great shape, then an
accident happens and the wire is damaged and now suddenly you got an issue.