Aluminum Anode - Please Help

[poppi57]

So I have read enough about using Aluminum anodes instead of zinc on an aluminum hull. I have a 22' aluminum alloy center console. I keep the boat in a slip in salt water May thru November. I just removed the zinc anodes the marina placed on the boat last year to replace them with aluminum anodes. I discovered the the surface underneath where the anodes were bolted to the boat are primered and painted. Do the anodes need to be in direct contact with the aluminum - no primer or paint? Or is it ok? I may have already made the mistake of sanding down the primer and paint to bare aluminum. This is very frustrating because I reached out to boat builder and he said it's fine it does not need to be in direct contact with bare aluminum. As long as you have the anodes attached to boat they will sacrifice themselves without any damage to boat. Should I be reprimering and repainting the areas I bolt the anodes to? Please help put my mind at east.

[Challenge]

I was always told to mount anodes directly to the aluminum, Whenever I change mine I sand and clean to get a good connection!

Good Luck & Stay safe

[poppi57]

Thank you - that's what I thought, it should be metal to metal contact for desired results. It's amazing how many people in the industry including some local marina's in CT believe that zinc is just fine as an anode on aluminum boats and it does not need to be in direct contact with bare aluminum.
Stay safe and let's hope we're in the water soon.

[Challenge]

Where in CT are you located? We keep our boats in Westerly RI and are in Eastern CT waters often.

[poppi57]

I'm in Stonington at Walkers Dock - not far from you at all. Where in Westerly are you? Are you in Greenhaven? I kept my boat there end of Oct/beginning of November last year for togging. I recall seeing a pacific there.I have 22' center console painted gray.

[kmorin]

pop,
if the anode is to protect from stray current (as in flow of electrons!!) then "conductive contact" with the hull is probably a high priority order!

Anodes should be mounted so there is no electrical insulation from the hull. Many builders bolt them on- but that connection can, and does, develop "resistance" at the bolt to aluminum hole!! So weld-on tabs are the least resistance- but if they're bolted, sand the back of the anode element till its smooth and flat, and bolt it to a clean flat plate on the hull, use hot dipped galvanized bolts if possible: NOT SS of any alloy!!!

There should be no paint on the anode, bolts, weld tabs, OR the mount plate between the anode and plate- there should be nothing that can create a resistance greater than Zero Ohms from anode to hull.

if at all possible, anodes should be mounted to dedicated plates- not bolted through the hull panels so a leak path into the bilge is created.

if someone expressed a different point of view? they are potentially uninformed.

Cheers,
Kevin Morin
Kenai, AK

[poppi57]

Kevin,
Thank you for your insight. You have confirmed what I thought was the right thing to do. I purchased aluminum alloy anodes - 6" x 3". The back of
the boat has dedicated mounting plates for the anodes. I'm so glad you mentioned the hot dipped galvanized bolts because I lost sight of that. I removed the old zinc anodes and was about to mount the aluminum but the bolts are clearly stainless steel. I will need to find a place who sells hot dipped galvanized or possibly aluminum but not sure if they even make them. The dedicated plates have been sanded down to bare aluminum. I'm sure there was less of an issue at my marina - no shore power of any sort - and I'm at least 100 ft from the building. Smaller marina with few amenities. Hoping that helps as well.

Thanks again for piping in. Greatly appreciated.

Sal (aka poppi)

[Challenge]

Hi Sal,

We keep our boat in Quonnie pond. My kids all sail out of NESS so we are around Stonnington all the time. What type of boat do you have?

Cheers


Rick

[poppi57]

Hey Rick,
I have a 22: Winninghoff Center Console. I don't know how to post a picture but feel free to send me your email or phone I can send a few pictures.
Boat is one of a kind. Jack built it 6 years ago for me.

[Challenge]

Yes I think we both complemented each others boats a few summers ago by the Stonnington breakwater, see you on the water!