Aluminum Hull - Placing Zinc Block to avoid electrolysis

w2much · #1 November 24th, 2006, 02:21 PM

Ready to finish my flooring on my hull. This boat has quite a bit of electrolysis damage to the hull. I was told to fasten a zinc block to the hull as this would deter further damage. Also I was told to connect a ground to the battery to the zinc block. Does this sound right? Or is just having the zinc connected to the hull sufficient? Any advice here is appreciated. Thanks.

tashasdaddy · #2 November 24th, 2006, 04:47 PM

is this boat going to be trailered or moored. if trailering i wouldn't worry, just a good rinse after salt water use.

w2much · #3 November 24th, 2006, 05:18 PM

The boat will be trailered as long as I own it. I do always rinse my boats to the excess after using in salt water. Should I then just attach the zinc and forget about the grounding? Thanks for your reply tashasdaddy.

Solittle · #4 November 24th, 2006, 08:54 PM

Also I wouold suggest removing the battery cables at the battery. I do this even with fiberglass boats to eliminate any stray current.

w2much · #5 November 25th, 2006, 11:36 AM

Quote:

Originally Posted by Solittle

Also I wouold suggest removing the battery cables at the battery. I do this even with fiberglass boats to eliminate any stray current.

Does a battery switch such as Perko perform the same function when turned off?

Solittle · #6 November 25th, 2006, 05:24 PM

They are supposed to. When I got my present rig I was careful to turn the master switch off after every trip. If I let the boat sit for a month or so I would have dead batteries. I started disconnecting the cables and the problem went away.

Bob_VT · #7 November 26th, 2006, 08:56 AM

You might want to take a hard look at why the corossion started. I would also reccomend that you coat the hull on the inside with gluvit. Someone did something wrong is you have that much corrosion. Look around for dis-similar metal fasteners in the aluminum. The corrosion can be like rust cancer if you do not get a handle on it.

Chris1956 · #8 November 26th, 2006, 09:54 AM

W2much, The hull of your boat should already be grounded to the block of the motor. If you attach a zinc to the hull, it too will be grounded. No need for a further ground. If you trailer your boat, you do not need to add the zinc, or disconnect the battery with a switch or by the cable. You also do not need to add anything to the interior of the hull, unless you want to. If you leave the boat in the salt water, you need the zinc, and you had better not have any shorts in the electrical system, or the galvanic corrosion of the hull may increase.

I suspect SoLittle has a short in his electrical system(blown diode in his rectifier??), causing his battery to lose charge.