please team you can do it , a cargo ship for mayhem (and the hospital,and the airport)
more things to make a medium city for mayheeeeeem
thanks a lot for your incredible-fantastic work

What kind of a cargo ship could one fit on a table? Only tiny ones roughly the size of the average Maiden build. River boats, barges etc. Maybe a Channel Islands ferry of some kind. Agreed, Mayhem Marina needs more boats, it looks at the moment like it is suited mostly for pleasure and charter craft, not the fishing and work craft it comes with.
But it is therefore not suited to serious freight, so you will only have the tiniest freighters ever to sail the seven seas.
I have looked up a name I see around these parts, Glorious Halo, and come up with the size of her sister, Emerald Halo. Translated to WWGs preferred 1/60 scale, the resulting model would be well over three and a half metres long, and more than half a metre beam.

This tape measure is only 3m long. (yes I know I need to vaccuum.)
The size of such a model will be roughly the length of the entire room.
I know someone who builds ships that big. They're nowhere near the scale, and yet bigger than he is; needs to unbolt them in the middle to fit his Titanic in his van, and it's only 1/78 or so.
Any large modern ship would have to be modular so it could be transported, and built in a repeating style so one would not have to print out and make an entire ship to put on the table at once. In which case I've no idea how you're supposed to put in the main holds. They'd be half a ream each.
http://au.wrs.yahoo.com/_ylt=A0S0zvguKT ... rrier.html
Otherwise, as this link shows, you have to live in a hangar.
I think what you have in mind is a cargo ferry of some kind?

woah, that really puts things into perspective Imagine a 1/60 Death Star

Forget the Death Star - I wanna see the Forge 'Spaceball One.'

over 1 Mtr are a good begin for a cargo ship of medium size
to put containers and some miniatures
(1 mtr long ,30/40 cms. width) I think its ok

A 4' cargo ship might be big enough to be usable and look okay next to a mayhem build.