Not all plastics are the same as cheap
PVC which should never be used below the water line. Nylon and Marelon are far tougher alternatives if you do not want to use bronze
or stainless, and they do not corrode. If this is a wooden hull, be sure to seal the wood very well before installing the through hull!
When installing the through-hull, apply the sealing compound like 4200 and only crank up the nut finger tight. Next morning, after the sealant
is solid rubber, tighten up the through-hull properly. You should see a slight bulging of the rubber sealant
around the edge of the mushroom head
where it has been compressed slightly. This ensures that it has not only been chemically sealed, but mechanically sealed as well. It will never leak.
Another suggestion: Sometimes a little foresight can save a calamity. Instead of having a simple in-line sequence of the through-hull, followed by the valve, then barbed adapter and then the rubber hose which leads to the strainer, I suggest installing a T after the valve. In this new position, the hose now runs parallel to the hull because the barbed hose adapter is installed on the base of the T. This leaves a straight line between the through-hull, valve and the other side of the T, into which you install a plug
. Why so?
This ensures that should you have any blockage from weed, or a plastic bag occur, you can remove the plug
and stick a wire or long screwdriver down and right through the valve and through-hull and push the blockage away. You will get a bit of water gushing in, most of which you can stop with your hand, but it should be a minimal amount if you are quick. But at least the problem is solved
. You could even do this to remove some molluscs.
Last time that I did this to clear a plastic bag, I shipped about 2 cups of water and it took about 30 seconds till it was plugged again. And all this costs is the price
of a T and a plug.
One more thing while I am on a tear - try to route
your incoming raw water
hose so that you do not have to remove it in order to replace the belt on your engine. Unbelievably, this problem is often the case. Often this adaptation just means adding one or two inexpensive fittings, like 90-degree elbows, to the raw water pump
so that the hose can now lead back close the block and then around to the strainer. Use nylon ties to hold it in place. You do not want to have to fight to remove a stubborn and old, well-adhered hose and deal with water etc if all you must do is replace your belt in an emergency!