Just a reminder to check all your connections regularly.
I had an issue (still sorting out) with the plug & wiring at the base of my finder.
Today I decided to check an in-line waterproof connector I have had cable tied in place for 2.5yrs & was shocked to see the state of the pins inside. Admittedly when I fitted the wiring I didn’t apply dielectric or anything thinking it would be fine but not so. Anyway I’ll be chopping this off & doing a more permanent join with a final sheath of epoxy Coated heat shrink over it.
Not sure if you can see green oxidation one side & blackish oxidation on the other.
Salt water is brutal

Yep I have to reduce replace those at times. Also check your fuse caps and holder contacts. Even if these connections haven't failed they can provide enough resistance to cause substantial voltage drop.

My wiring is ok ,the FF kept working for about an hour or so while the yak was capsized recently ,had to turn it off in the end which was a good thing as the battery terminals were about to implode

With the money they cost I don't know why they don't gold plate them, about the only thing that is almost impervious to salt.

I had an idea to clean the female/sockets of the plug & that was to use a Dental pick (like a mini bottle brush).
You can make a caustic solution with salt & vinegar to use with it if it’s badly corroded & brush/floss each socket then when finished neutralise with diluted bicarbonate of soda (thanks to the Instructables link Shane gave me).
Once finished use the pick again with some dielectric grease.
Not sure if it shows in the photo but you can see the pick/brush has green oxidation on it