The AT came with "plastic" hull valves.... I was assured they would be fine. Yea right.
I had them replaced them with bronze hull valves, bonding them all back to the zincs. Of course, while out of the water, I changed over from 1/2 to 3/4 inch hull valves for the A/C and gen at the suggestion and recommendation of the builder.
Speaking of which, the A/C system kept failing due to S/W flow or lack there of. I blew out the system backward through the hull valve, more than a few times.... The A/C would work for a bit and fail again on HP. Stumped, I called out the tech. He went over it and began to look stumped too. Suddenly a light went off and I suggested he remove the hose between the hull valve and the strainer. He did it and low and behold, he found a chewed up plastic bag in the hose. Seems the Little Giant s/w pump managed to suck a plastic bag through the hull grating. It would stop the water inflow and when the system shut down, it would temporarily loosen its grip on the water flow. We both looked with disbelief..... not a word was said. He removed the bag, put the hose back on, I paid him and he left. It was a learning moment to both of us.
The way I survived the FL summer heat, until the tech arrive was, I have a spare strainer cover into which I had a hole drilled and a stub bronze screwed in, on to this a secondary ball valve and a hose fitting. (I use this when I back flush the system when cleaning the sea strainer) I happily ran a hose from the anchor s/w wash down into the pilot house, down into the engine room and attached it to the top of the valve cover gadget. Worked fine, no complaints.
So folks, to make a long story short, it is possible to suck a plastic bag through the hull grate and have it lodge in the hose before the strainer. That piece of hose is about a foot long. If the light had gone off 2 hrs earlier I could have save the money for a tech call. I would charge you folks for the lesson. SMILE