Oxidation or ?

This boat is 24 years old. Fished 2 times this year then noticed this on hull and motor.Scrubed of with baking soda and dish soapLooked good sat for a week still looked fine took out for 5 hours and now looks the same as when I started. any thoughts on what it is or how to fix it?

I took sometime off from working on boat.Never really did find the smoking gun per say.Changed anodes went thru all the wiring I could get at. Pulled bilge and live well pumps,went to my buddys for 8 days and fished in his boat.Ran my boat for 6 hours today and all appears fine.Time will tell. Thanks for all you're input thought links ect.Hope I don't have to repost this.

Marine-Grounding-Systems

Assuming you found your motor frame and hull were electrically connected, so there must exist a voltage difference between them and something else that is in the water for galvanic corrosion to occur.

Since you mentioned a kicker, see if the frame of that is connected to the hull.

The severity of your issue implies to me that there is a very significant amount of current flow....

The last 2 days I have checked all wire conections  and any place wires can contact hull. Had planned to use it today that did not work out.Tried info in link on trouble shooting elct. problems and did not find any.Thank you for the link Bass.Trolling motors have there own batt.Nothing else on it.My othere thought is troller on rear is bad.14 years and gets run everytime out.

Are you using your main battery for your trolling motor? This has been known to cause corrosion issues if not done correctly.

Sure looks like galvanic corrosion to me.

Make sure the frame of the motor and the hull are electrically connected.  Sometimes there is an actual wire, sometimes not.  Yours may be missing.

as fast as its happening ....make sure you dont have electric connection short to the boat hull   

how-to/locating-ground-faults-current-leaks-and-short-circuits

Thanks for the input.Both anodes were in place but severly corroded.Found some replacements localy and bought them today(27$ -40 hp Honda} will install in morning and reclean boat.Will be out later in the week will let you know how it goes.

Make sure the sacrificial anode on your motor is still there.

Galvanic corrosion...my guess