Thanks Richard, I'm going to base mine loosely on MT Lorraine, an Aussie tug based in Queensland.
Lorraine: Specifications
General Specifications
Survey (QLD) USL 2B (4 persons), USL 2D (6 persons)
Length 15.3 metres
Beam 4.7 metres
Draft 2.0 metres
Displacement 47.8 tonnes
Bollard Pull 7 tonnes
Fuel Cargo Capacity 20,500 litres
Water Cargo Capacity 2,000 litres
Machinery & Equipment
Main Engines 2 x 300 hp Cummins NT855
Generator 1 x 12 kva Nissan


now it's calculator time to figure the scale, just on 1/48th so "O" Gauge figures will be close enough.
The only other pic I've found is from the bridge to rear over the stern.
Damien