Gimbal housing border with no paint

[BigDog98]

Can someone please explain to me the whole point and idea behind leaving a boarder of clear gelcoat around the gimbal housing? I was told that it prevents outdrive corrosion but can't understand why , all the boat's at the marina don't have it along with my boat. I am currently stripping down all the old paint and applying new barrier coats and anti fouling coats so I can leave the boarder if it is so crucial. I boat in the Logisland Sound so it is saltwater. Also can I paint the area where the gimbal housing is with barrier coat and just leave a border of no anti fouling paint around the housing? Thank You

 

[Chris1956]

Traditional antifouling paint has copper as it main antifoul ingredient. If the copper in the A-F paint contacts the aluminum in the outdrive, galvanic corrosion of the outdrive will occur at an accelerated rate. That is why A-F paint for outdrives and aluminum hulls is different than A-F paint for fiberglass. The gap between the outdrive and the F/G A-F paint helps prevent that galvanic corrosion.

You should be using an A-F paint made for aluminum on your outdrive. Make sure it is primed and painted well, before application. Those spray cans don't work very well. I like to brush 2 coats of Trilux or equiv. on the outdrive.

 

[Fun Times]

Here's some more corrosion info you BD, http://download.brunswick-marine.com/faq/mcm-corrosion.htm

Can I use anti-fouling paint? Anti-fouling paint may be applied to boat hull and boat transom, but you must observe the following precautions:

• IMPORTANT: DO NOT paint anodes or MerCathode system reference electrode and anode, as this will render them ineffective as galvanic corrosion inhibitors.
• IMPORTANT: If anti-fouling protection is required for boat hull or boat transom, copper or tin based paints can be used if not prohibited by law. When using copper or tin based anti-fouling paints, you should avoid any electrical interconnection between the MerCruiser product, anodic blocks, or MerCathode system and the paint. Allow a minimum of 1-1/2 in. (40 mm) UNPAINTED area on the transom of the boat around these items.
• Sterndrive unit and transom assembly should be painted with a good quality marine paint or an anti-fouling paint that DOES NOT contain copper, tin, or any other material that could conduct electrical current. Do not paint drain holes, anodes, MerCathode system, and items specified by the boat manufacturer.