Well lads, I hope we're not confusing merchant shipping with warships?
I'm looking at every (RN) capital ship forecastle deck I can find and it's only a small... very small percentage of shots that show them fitted. NELSON during an public open day, some (1) of HOOD during the mid-20's or mid 30s. Non of the wartime shots of Battlecruisers show these plates... and they are gratings with holes and slits across them, not a solid plate of steel. I'd hardly think they'd stop enough water up the pipe to be worthwhile to make and fit them. Plates? yes... grating? It's clear that they are to stop a foot (or man) disappearing down the pipe itself.
This is LIONs forecastle deck (plan):

I need to know if these gratings are those flat pieces drawn fitted in the hawse pipe or whether the grating sits atop of the hawse pipe rim moulding (the bit that protrudes just above the planking)? Here's where I am:

See the new brass etchings and the original plates across the pipes? I don't know whether these etchings are
instead of or
addional to the plates in the pipes.
Here's HOOD:

and this is NELSON:

On these 2 ships, the plates are sat atop the hawse pipe rim, in my LION plan, they appear to be sat slightly down
in the pipe... and they don't have the grating 'slits' depicted that the others do in real life.
Are my etched versions 'in addition to' or 'instead of'?
Jeez.. I've just realised what I'm missing and how I should have finished the edge to the planks... it's those cuts that andy (dreadnought72?) has been doing. I thought it was just as gap of plain grey painted deck between the planks and the hardwood 'spurnwater'. As Homer would say.. 'Doh!'