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[RRS01]

Understand that this is from a landlubber,    so please don't get too upset with me if I get some of the terms wrong   

From my understanding, the top deck was 'crowned' (from starboard to port) to allow water to flow off through the scuppers (??) 

My question is, were the lower decks also crowned or were they flat? and if they were also crowned, did they also have scuppers (provided they were above the waterline, of course) or did any water somehow flow down into the bilge, to get pumped back up to the top deck by the bilge pump, to find it's way back out to a scupper and overboard?

Thanks!

[BarryM]

You're almost there; the term you are looking for is 'camber' such that the deck at the centre is higher than at the sides to assist water shedding.
Camber is calculated according to a formula which you will find elsewhere on this Forum. (Got to leave you something to do.)  As far as I am aware the lower decks on wooden vessels were similarly cambered but without scuppers.
You're correct in saying that any water taken in is collected in the bilge, sucked out by a deck-mounted pump and returned overboard.

Camber for steel ships is another matter. While many (most?) have camber on the weather deck the lower decks are usually flat. On some very large vessels, camber is dispensed with altogether.

Hope this helps

Barry M

[RRS01]

You're almost there; the term you are looking for is 'camber' such that the deck at the centre is higher than at the sides to assist water shedding.
Camber is calculated according to a formula which you will find elsewhere on this Forum. (Got to leave you something to do.)  As far as I am aware the lower decks on wooden vessels were similarly cambered but without scuppers.
You're correct in saying that any water taken in is collected in the bilge, sucked out by a deck-mounted pump and returned overboard.

Camber for steel ships is another matter. While many (most?) have camber on the weather deck the lower decks are usually flat. On some very large vessels, camber is dispensed with altogether.

Hope this helps

Barry M

Yes it does! Thanks!! 

[brianB6]

Even smallish ships may not have a camber.
The Australian Armidale class patrol boats have a flat deck throughout.
You need to check pictures of the ship you are building.

[Colin Bishop]

Modern ships are unlikely to be built with cambered decks as it is cheaper to construct them with flat ones. As the ship rolls the water will tend to find its way to the scuppers anyway. The camber is more use in port when the ship is static and you need the water to run off, particularly if the decks are of wood. With modern coatings, standing water is not so important although I've found that it can be a nuisance on the decks of ferries when puddles form on the undeven surface and you put your foot in them!

Colin