I leave my Boston Waler jetboat moored behind my lakefront cabin for several
months each summer with no problems so far, other than having to clean the
scum-line off the boat hull after I take it out for the winter. It's
freshwater. Sal****er would cause much more corrosion of the jet assembly
and engine, as well as allowing for marine growths like barnacles and slime.

I have been offered a jet boat from the 1970's.
Can a boat like that be left docked or does it have to be taken out of
the water like a jet ski ?