Marelon and PVC

[Jmac62]

I am replacing some thru-hulls and removing the old seacocks from the head that no longer exists. My plan is to use marelon thru-hulls and then to cap them. Since there are no marelon caps (not made) I was thinking pvc. Bronze is too expensive and I want to keep the thru-hulls option without patching the holes.

[k1vsk]

Patch the holes, use bronze seacocks, sink the boat - your choice. Just curious - what is "too expensive" when compared with the loss of a
a boat, the liability of removal of a sunken boat, environmental liability, etc...?

[Maine Sail]

Originally Posted by Jmac62

I am replacing some thru-hulls and removing the old seacocks from the head that no longer exists. My plan is to use marelon thru-hulls and then to cap them. Since there are no marelon caps (not made) I was thinking pvc. Bronze is too expensive and I want to keep the thru-hulls option without patching the holes.

If you want to cap thru-hulls then use a Marelon valve (NOT PVC) on a Marelon thru-hull and close the valve. The safest choice is to patch the holes with a tapered repair. It is not a good idea to mix different materials below the waterline that have differnt thermal expansion coefficients such as Marelon & PVC or Marelon & bronze. PVC should be avoided at all costs for below waterline use as it fractures easily and is not a reinforced plastic product. I have personally seen a Marelon valve cracked that had been threaded onto a bronze thru-hull..

If you MUST cap the Marelon thru-hulls a bronze cap is a far better idea than PVC but it is still not a good idea due to mis-matched threads. If you must mix Marelon & bronze the male Marelon should thread into the female bronze. Avoid threading male bronze into female Marelon..

[tager]

NPT caps are not that expensive in bronze...