Corvette Engines to Kingston

In a previous post on the River Street bridge, you'll read about the raising of the bridge during wartime. This not only led to its precarious nature, it also was necessary to bring in the Inglis steam engines for corvettes built at the Kingston Shipbuilding Co. shipyards during World War II. While I haven't seen any under-construction photos like the ones below taken at our shipyards, 

On July 10, 1942 at a city Board of Works meeting, the request from Kingston Shipbuilding Co. was received and referred to the finance committee. The Cataraqui Street [sic] bridge was to be raised 14 inches:

City Council meeting minutes show that approval was given to raise the bridge to allow the marine engines built by Inglis in Toronto to pass underneath, although that motion was approved on July 16, 1942. The granting of the request by Kingston City Council was published in the July 17, 1942 Whig:

The work was taking place quickly, in August, with costs apportioned to CN for the bridge and city for the approaches to allow boilers to pass underneath:

Also in mid-1942, expansion was taking place at the shipyards for corvette construction. Sheer legs adjacent to the lake were being built, with a 100-ton capacity. Their first lift was an 83-ton marine engine. A new 125 x 75-foot machine shop with an overhead electric crane to permit unloading from Ontario Street siding was also being installed. The crane was being installed "to lift the heavy pieces of machinery and steel which come in on the Ontario Street siding and carry them right into the building", according to a June 19, 1942 Whig article. Notice that this engine is even on a depressed-centre flat car to minimize its height:

Four-cylinder, triple-expansion steam engine and two boilers, destined for HMCS Galt alongside at Collingwood Shipyards, December 1940. One of two fire-tube boilers (below) for HMCS The Pas also at Collingwood in December, 1941. Note the comparative size of the shipyard worker! From Corvettes of the Royal Canadian Navy 1939-1945 by Macpherson and Milner.

This cutaway illustraion shows where they were located in the corvette. Engine (red arrow) below engine-room skylight, and fore and aft boilers (yellow arrows) below the funnel.

The 1939-1940 construction program Flower class corvettes were fitted with two Scotch Marine "fire-tube" boilers. These boilers "...held the water inside the huge drum of the boiler and the "fire" was shot through it in tubes which started in the three fireboxes at the bottom and then snaked back and forth through the drum." The large volume of water contained in these boilers provided a large reserve of steam for hunting submarines, but meant that the boilers were slow to raise steam from a cold start. In addition, the Scotch Marine boilers turned out to be relatively unreliable, and their size limited the supply of fuel that could be carried.

Scotch marine boilers were basically large round drums filled with water, with three combustion chambers built into the base. Heat from these oil-fired chambers snaked through the water in a series of pipes until it was vented out the funnel. The steam was drawn off the top of the boiler through high-pressure pipes to the engine. Apart from the ease of construction and operation, the advantage of fire-tube boilers was that they held a large reserve of steam which was useful when a ‘sprint’ was needed to catch a whale—or a submarine. But the large Scotch boilers also limited the size of the fuel storage tanks on either side of the early corvettes and kept their range to approximately 3,500 miles at 12 knots, or 2,500 at their maximum speed of 16 knots.

The 1940-41 construction program ships received "water-tube" boilers instead, in which the main body of the boiler acted as a firebox and water passed through it in banks of tubes. These boilers were superior in most respects to the Scotch Marine boilers that they replaced, and later allowed for more fuel to be carried thus extending the range of the 1941-42 construction program onward.

The 70-ton boilers provided steam to a four-cylinder triple expansion steam engine generating 2,750 horsepower, and providing a top speed of 16 knots. The corvette’s four-cylinder, double-acting vertical triple-expansion engines were old technology, too, perfected in the 1880's. Their great merits were ruggedness and simplicity, and the fact that they were so ubiquitous that finding engineers to run them was not a problem. The engines drew steam from the boilers at up to 200-pounds-per-square-inch pressure and used it to drive the high-pressure cylinder. The steam was then bled off to the intermediate-pressure cylinder before being sent to two large low-pressure cylinders at either end of the engine (hence ‘triple’ expansion with four cylinders). The exhaust steam was routed back into the boilers via a condenser. These engines were remarkably durable. HMCS Sackville’s power plant operated for 40 years!

(above from a variety of online sources, 

including the excellent 'Humble Corvette' series in Legion Magazine.)

This photo (below) shows the bridge with taller timbers and the previous limestone abutments, and the gap between them! Later photos than this Queen's University Archives 1965 photo show the abutments being concrete-encased.

Correspondence from 1940-41 between John Inglis, Collingwood and Kingston shipyards:

Here are some additional advertisements for marine boilers as published in a September 26, 1942 National Post special section on wartime shipbuilding. Inglis was not the only supplier.