Marinette Boat Forum

aluminum anodes in salt water?

Yes, aluminum anodes in salt water.

If you've ever run a, say, 20 foot IO boat, then you'll appreciate that keel! My 32 footer tracked dead straight, hands off the wheel, as we negotiated miles of no wake zones. By comparison, a 20 footers with IO drive waddle all over the place, even with constant steering corrections.

Jeff

Keep the keel fin, it came from the factory
Wally from Hoohaah 39' also

I have a 39 Sedan and that keel is original and necessary, tracking is good and sorted out from the factory, you can feel good about keeping it original and the anode system is as well is optimized from the factory.

The yard guy here in Rockport insists that the keel fin should be seam welded back in place to prevent electrolysis from attacking the hull in the poorly insulated spaces between the welds and that the sacrificial aluminum anodes should be welded to the fin or the bottom of the hull to insure good contact. He says the hull will not be protected otherwise and the stainless steel bolts will set up galvanic action with the anodes. Apparently, the hot salt water of the gulf requires extra precaution.

He is full of crap. Totally full of crap. Just do it like the factory did, and I would find somebody else to do it.

Your yard guy is either well intentioned but woefully mis-informed -or- trying to sell you on work your boat doesn't need.
The welds that exist between the hull and the keel are TOTALLY sufficient for protection. If these are the original welds, they were done in such a manner as to never fail to provide continuous connectivity.
Many members of the forum use the stainless steel method of bolts (nuts and washers) to attach/hold the anodes to the keel. It's not a perfect system. Water (fresh/brackish/salt) will get between the anode and keel. BUT... the protection there is fine. The anodes will be sacriced, as is the intent. You shud pull the boat (as you would need to do if the anodes were welded to the keel - which you shouldn't do), unbolt the anodes (replace if needed), clean them up if good, clean the keel surface, and then bolt back on.
Think of it this way...
You can pay the yard guy to weld the anodes on and then pay him again to do the regular mainteance/checking, and then pay him to weld the old (or new) anodes back.
He'd have to run a watertight weld around the anode to ensure there'd never be any corrosion (and subsequent potential loss of galvanic protection). Such a watertight setup would be time consuming. That isn't gonna be cheap!!
-OR-
You (or he, if you trust him) can use the tried and true methods of clean up and bolt on. It's quicker, just as reliable (when part of regular "out of the water" maintenance), and far, far more economical.

Bill

For heaven's sake DON'T weld the anodes on! Bolt them on, as the rest of the world does.

That guy's a nut job.

Jeff

Aluminum Cruisers Inc knew what they were doing. Bolt them on. I have never seen any galvanic reaction between the SS bolts and the anodes or hull. Now if you are still concerned here a couple of things you can do to ease your mind.

1. Mounting surface of keel Must be clean and bright.
2.You can use silicon or whatever to coat the SS bolts to isolate them from the hull.
3. Run a bead of 5300 around the anode to keel joint to help reduce water penetration between anode and keel.

I have done all of the above and it worked fine. I also have done none except clean contact between anode and keel and saw no difference in the result. While the boat is on the hard check you anode condition clean them and most important check continuity between the anode and the hull. If good leave them alone.

I like Fast Jeff use a mag. hung over the side anode while at the dock. I have done this with this boat now for 12 years. It not only keeps my hull protected...I have seen little deterioration of the Keel, rudder and trim anodes. DO NOT USE A mag. anode in salt water. Hauled 18 months ago and just cleaned, checked done!

Boatzincs.com has the correct anode strips and over the side anodes for our Big M's.

http://www.boatzincs.com/hanging_anode_aluminum.html

Here is the link for the Strip anodes for our Big M's

http://www.boatzincs.com/marinette-bar.html

safe harbors
dave