Singin' the electrolysis blues . . . .

I've been running my own boats since I was 7 years old. I've been a scavenger since I was a kid and all my boats were boats that were found and in various states of disrepair. I'm used to leaky aluminum boats. When you find a boat in the marsh after a hurricane and can't track down the owner, you take what you can get. A few years ago, after moving from Louisiana to Texas, I purchased my first "real boat", meaning that it was a boat that had its own trailer. It's a 1984 Lowe 18 foot center console XXwide. I call her the "Ugly Mudda". Anyway, she didn't leak when I got her, but now she does, like a collander. I patched a few holes with JB weld (Not the best option, but I'm a teacher and therefore poor), and I finally consulted a professional. His advice was anything but uplifting. - Sell it and get a newer boat. A few of the holes appeared to be pin holes, but when I pushed on them with my finger, the aluminum fell apart. To boot, the motor blew without warning, but I luckily picked up a 1974 Alumacraft 1872 to keep me on the water the last 6 months while I saved up for a new motor. It has the same problem by the way, but at least the motor runs. (It's an even worse basket case acording to the aluminum guy.)

So I'm going to keep on keeping on until I can save up for another boat. But the question begs itself, How can I make sure this won't happen to the next boat? I'm in salt water only. My boat spends at least 2 days a week in the water as I have a fishing camp that you have to use a boat to get to. I know that bunk board carpet causes electrolysis. I've heard about putting a sacrificial anode (or is it cathode?) on the hull to stop this, but I have had many conflicting pieces of advice regarding the type of metal to use, and if I should connect it to the negative post of my battery. Also if it should be above or below the water line?

It thought this would be the best place to come and ask all these questions. Y'all help a guy out woudja? - Sandy

Looking forward to responses on this, I mainly fish salt water and am worried about this as well. I watched electrolysis destroy my father n laws 94 Gruman and his vary rarely saw salt water. Transome was full of pin holes was waiting for the motor to fall off.

Every time i come in I wash the boat down and partially fill the hull with enough fresh water to fill the area under the floor. With the salt water working on my springs one day the springs are gonna give when i do this i know but atleast it will be in the yard and not on the side of the road on the way to the landing. I haven't seen any problems with the boat yet but i do see it destroying my trolling motor.

I ran a 19' Sea Nymph in the salt for a number of years and had no problems with electrolysis eating at the hull. Used sacrificial anodes on the engine and made sure that nothing grounded to hull.

Also, washed the boat with soap and water after every trip

While I may be a bit foggy on the dates, I remember when Lund came out with their "Marine Aluminum" hull.
It was around 1986-ish.
Had older boats that acted as you mentioned and used mostly in fresh. Salt and leaving a "tin" boat in or even by the water was considered a no-no around here. I definately saw the results and effects of salt on them older hulls.

Now days I believe about all the hulls are marine grade aluminum.
That Lund I had for several years. Used primarily in salt. The worst indication of use was the aluminum would turn a darker grey, but that was it.
I've no idea how to check / verify "marine grade", nor the actual year(s) the change took place. I suspect that by 1990 most went with the marine grade if it was a salty design. Sea Nymph, Starcraft, Lund, Monarch I know have been marine grade for years (or so I've been told).
Smaller flat bottoms I'd wonder about. Mostly because you see very few of them in the salt (at least locally).
Marine grade has a heavier feel to it is about all I can say for description and that's really reaching for a description.
Even polished the marine grade has a darker color. Hind of like a casting but only half as dark colored.
I remember on the older ones the guys would paint them if left in / around the salt. But from what I saw, it really didn't help much.
The marine grade aluminum is far, far better in salt. Still, I wouldn't plan on mooring / docking for extended periods of time if it were mine. That's where glass comes in IMHO. However, I've seen 20+ footers left in salt and owners claim, "No problems".

We had a 30' aluminum boat that stayed in the water for 25+ years that developed a electrolysis problem. After pulling our hair out for over a year, we discovered that we were getting stray electrical current through a faulty underwater light the dock next to us had. We ended up purchasing Electro-Guard https://www.boatcorrosion.com/product620FM.html It solved all of the problems, but it was expensive.

I have seen what I believe you are talking about. The metal is pitted, white residue, and brittle. This was on boats that was "say" just pulled up on the bank neglected and mainly not washed.

I have my aluminum boat in salt water just about every weekend and haven't had the first problem with the boat. The motor is a different story. I just replaced the anodes on my Yamaha and it is washed every trip. It's no different than your fishing equipment. If I neglect washing my rods and reels just one day later they will show signs of corroding.

If your going to play in salt water, you will deal with the salt or you will pay the price.

Floatsum said:

While I may be a bit foggy on the dates, I remember when Lund came out with their "Marine Aluminum" hull.
It was around 1986-ish.
Had older boats that acted as you mentioned and used mostly in fresh. Salt and leaving a "tin" boat in or even by the water was considered a no-no around here. I definately saw the results and effects of salt on them older hulls.

Now days I believe about all the hulls are marine grade aluminum.
That Lund I had for several years. Used primarily in salt. The worst indication of use was the aluminum would turn a darker grey, but that was it.
I've no idea how to check / verify "marine grade", nor the actual year(s) the change took place. I suspect that by 1990 most went with the marine grade if it was a salty design. Sea Nymph, Starcraft, Lund, Monarch I know have been marine grade for years (or so I've been told).
Smaller flat bottoms I'd wonder about. Mostly because you see very few of them in the salt (at least locally).
Marine grade has a heavier feel to it is about all I can say for description and that's really reaching for a description.
Even polished the marine grade has a darker color. Hind of like a casting but only half as dark colored.
I remember on the older ones the guys would paint them if left in / around the salt. But from what I saw, it really didn't help much.
The marine grade aluminum is far, far better in salt. Still, I wouldn't plan on mooring / docking for extended periods of time if it were mine. That's where glass comes in IMHO. However, I've seen 20+ footers left in salt and owners claim, "No problems".

Click to expand...

On that subject, the marine grade that the cookie cutter boats is 5052 aluminum. A true marine alloy is 5086.

Aluminum hulls can be marina stored for many many years without a problem. The key is the sacrificial anodes, and periodic maintenance. The fiberglass boat will need a different sort of maintenance than the alloy rig, but will still need much more in quantity.

Take a look around at aluminumalloyboats.com if you want to see some "real" alloy boats that spend most, if not all of their life in salt, and hear what the owners say about the maintenance, or lack thereof.