Hi the tug on the Blackheath stand was based on a tug working the Thames in the early 1930's. The model was built between 1937 / 38 and launched at Victoria Park that year under the naame "Marina". It had a refit in 1948 and had a bilge pump added driven from the flywheel.
It is all tin plate and brass construction with a twin cylinder 7/8 bore and stroke home built engine, centre flue boiler and petrol blowlamp.
All up weight is just on 90 lbs (ouch).
It will be on my stand at the Boat Show this week if you would care to come and poke around inside.
Phil