To Zinc or not to Zinc? Anode Anodes on AL Aluminum Boat

[Jim_the_Islander]

The premium glass boat, an extraordinary boat, that has taken me on many a successful trip, has a grounding wire running from all the stainless ss scupper drains, gate valve ss thru hulls, and a bronze anode on the back of the transom. On an aluminum boat is this necessary? Plan on using plastic thru hulls when possible. An exterior anode seems like a reasonable idea to say the least on a tin boat.

Please reply with pictures and thoughts....thanks.

 

[dingbat]

Two thoughts....
Imho..plastic thru hills have no place on a boat, at least not below the water line.

I personally know of two instances where plastic thru hulls failed and sunk the boat.

The bronze "anode" isn't an anode at all, it's a ground bar.

The bonding system is designed to keep all the dissimilar materials at roughly the same potential to minimize corrosion.

Changing the thru hulls to plastic reduces the number of points but doesn't eliminate the problem of dissimilar metals.

My recommendation is to keep the bonding system in place. Make sure your electrical grounds are keep clean and properly tied back to the battery. Keep a fresh anode on the motor suitable for waters you boat and go boating

 

[Watermann]

All my aluminum boats have non metal thru the hull fittings. Bilge, livewell drains, livewell pump intake. There's no problem with having thru the hull fittings being non metal. All the fittings thru the hull below the waterline are on the transom and if you knock those off on something then boating isn't for you.:lol: The fittings on the sides that could be damaged are above the waterline.

 

[Jim_the_Islander]

Plastic thru-hulls are fine on an AL boat, don't plan on putting any below the waterline. My glass boat has all ss thru-hulls. Plastic works good on a AL boat because the hull is so thin, you could never get plastics tight enough to seal on the irregular inside surface of a glass hull imho. Having all plastic thru-hulls will help on AL boat used in saltwater from having dissimilar metal corrosion.

Thanks for explaining the bonding system on my glass boat, thought that it was something like that.

So no metal thru hulls means no need for a bonding system. Anything else I attach to the boats electrical that goes in the water like trim tabs or trolling motor should have its own zinc attached and I should be good then?