Bilge pump through hull fitting sea cocks

[Desmo]

My Beneteau 323 has two above the waterline DZR through hulls for the manual and auto bilge pumps which I need to replace. They both have old sea cocks which are open and I have never closed as I can't see the point, especially on the auto pump outlet. The cocks look original and are serviceable. Heeled over the through hull fittings might just get submerged.
Are these cocks actually necessary for above the waterline skin fittings? I am thinking of discarding the sea cocks as part of the through hull upgrade. Am I missing something? Would a non-return valve be just as good if preventing ingress, if that is what the cocks are there for?

 

[Refueler]

I have a N/R valve for my auto bilge and TBH ----- its not reliable as any small bit of crud is enough to keep it open slightly. I have hand valve on the hull fitting ...... when boat heels - I can get water back through - so I close it while sailing.

I soon know when I have forgotten to re-open it ..... as my sink passes through same outlet !!

Honest opinion ? Stay with the valves .... maybe fit the N/R valve as a secondary line of defence ...

 

[neil_s]

I have no seacocks on my bilge pump outlets (just below the deck edge) but if Beneteau saw fit to supply them originally, I think you should refit them if they are serviceable. I have just removed my below waterline ball valves for a close inspection ( they were getting a bit stiff to operate) and found them otherwise in good order. A squirt of Wilko's bike chain lube with PTFE has restored them to silky smooth!