Sump Thru Hull Stains

[Surprise390]

I've seen a lot of newer Sea Rays and other boats at marinas and clubs here in Florida that have ugly rust stains south of the sump thru hull. These stains are caused by the A/C units drip pans rusting. I run mine on dehumidify mode full time, year round. My previous Sea Ray, a 1995 370da, did not have this problem so I suspect that at some point Cruisair had a design change. I really got tired of cleaning the stains off the hull so I called Dometic Group, maker of the Cruisair units used in both boats, and and explained the situation. They were very helpful and sent me two new stainless pans the insides of which were coated with what looks like the stuff they coat the inside of some truck beds with, for free. The ones I removed were painted steel. Installed them myself making sure that they drained properly and no more rust stains. Hope this helps someone with the same problem.

 

[fwebster]

That may handle the rust for a while, but once the temperatures rise past the mid 50's, you will still have stains. They will be green where algae is growing in the outlet fitting and lines near the thru hull.

I have eliminated them by turning a plastic fitting out of white nylon that extends the thru hull and changes its exit shape so that the drip falls into the water instead of running down the hull. Others use a short piece of plastic hose to remedy the problem.

 

[BON DIA]

Same problem, rusting AC condensation pan. In '08, under warrenty or their good graces, SR supplied new bare stainless pan & we split the labor with dealer, cost us $125. Also used the hose trick FWebster mentioned.

 

[Surprise390]

Luckily, no algae stains here. The stains I'm seeing in South FL are only rust and are from running the A/C daily.
The plastic hose in the thru hull might be OK if there were no other way of dealing with a small algae problem but it's definitely not a solution to a severe corrosion problem. PVC coated stainless is. I see people "fix" the problem down here with a plastic hose all the time though.