"Bob McMillan" wrote
...there is a 32mA current drain with everything turned off.

Lets see, 32ma x 100 hours (four days) is 3200ma or 3.2 amps of drain.
That's only 7% of a fully charged 44ah battery. Maybe your use of
fishfinders, etc., drains the battery heavily. Evinrude 90hp V4
allegedly has a 60amp alternator on it, 15 minutes on the trip back =
only 15 amps back into the battery. And that's assuming your 44ah
battery can take a 60 amp charge, 1.4 times the battery capacity. A
regular lead acid can't take that abuse, gel cells or AGMs might.

And that's assuming the motor's running near full speed; if you're
going slow the alternator could be putting out zilch. The battery
slowly slips into a nearly discharged state where 4 days takes the
last few amps out and you can't start the engine.

Take the battery home and charge it fully (or run around the lake for
an hour or so), then try running the engine for a half hour on the run
back, to keep it charged, or revved up a bit at the dock for a half
hour (that'll make you popular). A bigger lead acid, or 44ah AGM/gel
cell battery might accept a higher charge rate and allow you to get
away with only 30 minutes charging per trip.

That mystery 32ma current is probably keeping a relay open in the
engine or some such thing. Some regulators leak a little current when
not in use. Could be anything, but I don't think it's your problem.