New zinc placement on 1976 Mariner 2896

[Ctmangrum]

Putting my boat in salt water for the first time in a while and need recommendations for anode placements. Checked some of the posts but, there was a lot to dig through and couldn't get the answers I wanted out of 1 or 2 posts. Expecting to put anodes on the shafts and props. Not too sure about the trim tabs. Thanks.

[buster53]

Yes, put on trim tabs as well. Most likely, there is already a hole drilled in the tab for placement. What about that big zinc plate that actually goes on the hull stern?

FYI, you should have been using magnesium anodes when in fresh water.

[Ctmangrum]

They were magnesium at the lake. Maybe I didn't explain it correctly. Trying to figure out the correct placement for the shaft anodes. Lots of opinions and looking to see what the consensus is. Ill check the stern area for the placement.

[buster53]

Don’t forget your struts.

[Viper]

Your shaft anodes should be placed close to/just ahead of the struts. This way you protect the shafts and struts without mounting anodes on the struts themselves. The caution is that you don't put them so close to the strut that you starve the bearing of water while under way at higher speeds. Depending on the shaft diameter, I mount the anodes 6-12 inches ahead of the strut. The wider the shaft, the further away the anodes should be. Some will say put them less than an inch away from the strut but that's not a good idea IMO as you can starve the bearing. Water is what keeps it lubricated. The cuts/valleys in the rubber need to be water filled to lubricate the area while the shaft is spinning. Yet others will suggest mounting the anodes in the middle of the shaft between the stern tube and strut. Anodes however are more effective when in proximity to the most metal mass, which is closest to the transom to help protect the surrounding running gear. Anodes don't wear evenly which can affect the shaft turning true when mounted in the middle of a long run. It may not be noticeable but certainly can be especially when mounting more than one anode per shaft. Mounting at the supported section close to the strut eliminates this problem while still protecting the entire shaft.

As far as how many anodes you should have, it really depends on the application and conditions. Some will have just a transom anode, or transom and shaft anodes, and some will have transom, shaft, rudder, and tab anodes even though they may not be needed. The only way to be sure is to take readings at your slip. Having said that, readings will change when you go to another port. When considering anodes, you also want to ensure your bonding system is intact and that connections are clean and tight.