[BITList] Fw: hull valve blanking

[HUGH]

Colin,

Why would anyone fit blanks/plugs to an overboard or inlet on any vessel?  Three reasons come to mind.  Security/safety and convenience.  The first wouldn't normally be applicable to a merchant vessel in any normal circumstances, but a long forgotten application of the other came to mind.  A new-building in Scotts, either Blue Flue or BP - I did the underfloor arrangement and all the overboards and inlets.  The lower main sea inlets, P and S, had to have covers that would fit over the rectangular openings and grilles and be secured there against rubber seals by hooks going through the grilles. The covers were to be lowered on ropes and fitted by divers, so they were made hollow to increase the floatability. The idea was that the lower main sea inlet hull valves could be overhauled at sea.  I didn't fancy the idea at all, but it was a nice little design job.

With a warship alongside or in drydock, it could be a fear of nasty people sticking nasty things into unblanked openings.  Or, a nuclear sub might emit something noxious where it would be detected. Either way, sod all to do with relief valves.

Hugh.
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