by William Lafferty » November 22, 2022, 1:59 pm
The Bradley fleet had already adopted turbine-electric propulsion with the building of the T. W. Robinson in 1925. The general layout was not ideal but the overall performance and economy of operation led to Carl Bradley stipulating turbine-electric for his eponymous new build in 1926. Turbine-electric drive was adopted by Ford for the Chester and Edgewater in 1931 and the Pere Marquette had adopted it for the City of Saginaw 31 and City of Flint 32 in 1929 and 1930. Such an installation on the lakes goes back as far as 1908 with the sister fireboats Graeme Stewart and Joseph Medill of the Chicago fire department. Such an installation allowed the use of high speed steam turbines to drive the propeller without the use of heavy and cumbersome reduction gears, using instead generators and electric motors coupled to the prop. Compared to compound steam engines, turbines are very simple and efficient in use, with fewer friction producing moving parts, while the steam expended is condensed and reused by the boiler. The turbine could run constantly at its most efficient speed while the motor speed could be easily and quickly adjusted as needed. This was especially true for reversing. Maneuverability efficiency was definitely increased with electric, and which no doubt was a consideration when the vessels previously cited were designed. Turbine-electric drive was somewhat of an engineering fad in the 1920s and 1930 for merchant vessels. You will note, though, that Bradley's next boat, John G. Munson of 1952 was geared turbine, Ford's next NYSB canallers Norfolk and Green Island were Diesel propelled, and the next vessels in the former Pere Marquette fleet, City of Midland 41, Badger, and Spartan, were Skinner unaflows. At some point Diesels became more efficient, reduction gearing more advanced, and the weight of the generators and motors in the turbine-electric installations too onerous. An exhaustive article analyzing the performance of the Bradley's installation can be found in The Marine Review, December 1928, 29-33, 64.
The Bradley fleet had already adopted turbine-electric propulsion with the building of the [I]T. W. Robinson[/I] in 1925. The general layout was not ideal but the overall performance and economy of operation led to Carl Bradley stipulating turbine-electric for his eponymous new build in 1926. Turbine-electric drive was adopted by Ford for the [I]Chester[/I] and [I]Edgewater[/I] in 1931 and the Pere Marquette had adopted it for the [I]City of Saginaw 31[/I] and [I]City of Flint 32[/I] in 1929 and 1930. Such an installation on the lakes goes back as far as 1908 with the sister fireboats [I]Graeme Stewart[/I] and [I]Joseph Medill[/I] of the Chicago fire department. Such an installation allowed the use of high speed steam turbines to drive the propeller without the use of heavy and cumbersome reduction gears, using instead generators and electric motors coupled to the prop. Compared to compound steam engines, turbines are very simple and efficient in use, with fewer friction producing moving parts, while the steam expended is condensed and reused by the boiler. The turbine could run constantly at its most efficient speed while the motor speed could be easily and quickly adjusted as needed. This was especially true for reversing. Maneuverability efficiency was definitely increased with electric, and which no doubt was a consideration when the vessels previously cited were designed. Turbine-electric drive was somewhat of an engineering fad in the 1920s and 1930 for merchant vessels. You will note, though, that Bradley's next boat, [I]John G. Munson[/I] of 1952 was geared turbine, Ford's next NYSB canallers [I]Norfolk[/I] and [I]Green Island[/I] were Diesel propelled, and the next vessels in the former Pere Marquette fleet, [I]City of Midland 41[/I], [I]Badger[/I], and [I]Spartan[/I], were Skinner unaflows. At some point Diesels became more efficient, reduction gearing more advanced, and the weight of the generators and motors in the turbine-electric installations too onerous. An exhaustive article analyzing the performance of the [I]Bradley[/I]'s installation can be found in [I]The Marine Review[/I], December 1928, 29-33, 64.