Tweedbank (I)

It is ofen said that the "Irisbank" Class, of which "Tweedbank" is the last of the four was intended for Weir's "Round the World Service- Westbound" in the 1930s but it was felt that these ships would not be fast enough to compete with the "express" ships then being put on the joint service by other operators such as Wilhelmsen, Chambers, Kerr-Silver and Maersk. Accordingly, in addition to these Workman Clark units, two "flyers" were built at the Harland's yard: "Foylebank" and "Laganbank" to a similar design but with twin 8-cylinder oil engines instead of twin 5-cylinder oil engines installed in the "Irisbank" four.
The service had its own jointly-owned marine terminal on Staten Island in New York which was converted into a Bus Barn for the Metropolitan Transit Authority in the 1960s.

The "Irisbank" four were propelled by a pair of Workman-Sulzer single acting two stroke air injection engines each with five cylinders and the total power being 4,500 b.h.p. at 100 r.p.m.
The auxiliary machinery comprised steam on deck and a combination of steam and electric in the engine room. Two, 3-cylinder Fiat single-acting two-stroke engines being provided for electrical services with an output of 270kw.
The two built at Harland & Wolff were fitted with two 8-clyinder single-acting four stroke engines developing 4,300 h.p.