William Denny and Brothers Ltd built all the ferries that operated the Queensferry Passage from 1934 to 1964.
Maurice Denny championed the expansion of the ferry service in the 1930s, providing and operating two additional ferries on behalf of the London
and North Eastern Railway that aimed to supplement the services of the adjacent railway bridge. Their success allowed for the
addition of two more ferries in the 1940s and 1950s.
The Robert The Bruce was the first all welded vessel as well as the first with diesel-electric paddles. Details of the Paxman
used on the Robert The Bruce and Queen Margaret have kindly been supplied by Richard Carr.
Engines: Each vessel was fitted with two 8 cylinder MZ engines, marine versions of the 6½" bore x 10" stroke VZ engine, with individual ratings of 175/192½ bhp at 750 rpm. The four engines were despatched from Paxman during January 1934 and records suggest they were the only 8 cylinder MZs ever made.
Electrical Machinery: The propulsion motors had a speed of 270 rpm at full power. Each motor was coupled through chain gearing to one paddle shaft, giving a paddle wheel speed of approximately 45 rpm at full power. The main generators and the rest of the electrical equipment were manufactured by Metropolitan-Vickers Electrical Co of Trafford Park, Manchester.
he ferries only had a draught of approximately 4 ft. 6 inches which made them difficult to manoeuver in high winds.
Newspaper articles record how the ferries on occasions ran aground during gales. The number of times this occurred however was relatively few.
Their service speed was 8 knots and the 6 crew consisted of a Captain, Mate, Engineer, Ticket Clerk and two Deckhands.
Despite high winds, sea fog and the occasional breakdown the ferries ran at a 99.97% efficiency.