Introduction with questions....water in battery and oil compartments

[Nomad]

Took her out tonight on a successful sea trial and she ran very well starting on the first twitch of the key after sitting for a month.
Jumped right up on plane and planed out at a minimum of 19mph and WOT was 42mph and 5400rpm.
In for a mechanical inspection and informal survey with my marina inspecting for rot and structural issues. If all is ok then I will be pulling the trigger