[1234lb]

I have a 16 ft aluminum boat. Two weeks ago it starting taking on some water and upon inspection I found a small, 1/8" hole in the bottom of the hull, 2/3 back from the bow on the flat, horizontal surface. The floor is covered so I can't see if there is water standing in the hull or not. I also found some spots that appear to be corrosion spots (appears to be corroding from the outside going in since they are not leaking). They are closer to the bow (V-bow). I use the boat mostly for crabbing and fishing (salt/brackish) but it is trailered, never left stored in water. For extended periods (3-4 hours, I use the trolling motor while crabbing. The hull is not grounded to the battery (at least not on purpose). Is this most likely galvonic corrosion caused by electrolysis? What could be causing it? I have read that "reverse polarity" may be the culprit. Not sure what that means on a boat. How can I test/check for that?

[Stoutcat]

Hi 1234,

Aluminum corrosion? Thoughts:

* Drops of battery acid

* Abrasion

* Galvanic (Electricity is like life... it finds a way)

* Failure to rinse the boat with fresh water

* Anti freeze

* Exactly what kind of water are you fishing in?

Alan

[tashasdaddy]

salt lack of rinsing every use.

[1234lb]

I use the boat in salty as well as brackish water. I have friends that fish and crab in the same water I do and they never rinse their boats, have older boats than mine and don't seem to have the same problem.

The somewhat unique operational use of my boat is that I do alot of crabbing and use my trolling motor to pick up the traps. I am wondering whether that operational aspect is having some "galvonic" affect on my boat that is promoting the corrosion. How can I test if that is happening? Would the voltage be so low is would be impossible to measure it without highly sensitive equipment?

Puzzled???

[Stoutcat]

Hi,

Thoughts...

* I just did a quick Google looking for galvanic corrosion test equipment and it is out there, but very pricey... Basically, the equipment tests the voltage potential between your hull and the ground plane of the water... The stuff I saw talked about a differential of 0.6V and 1.6V. I guess this could happen if your trolling motor cables are cracked and wet. (http://www.boatus.com/boattech/MarineCorrosion.htm)

* The following is a fascinating thread... http://www.finishing.com/331/73.shtml

* But I doubt that that's the issue... I'd fall back to what TD said... Salt water is nasty stuff, and not all aluminums are created equal.

Alan

P.S. I've never used the stuff, but Durafix might come in handy.

[tashasdaddy]

gluvit is the aluminum boats best friend, for fixing leaks. i would still get some anodes on the boat and motor. is your battery in a plastic battery box?