I don't have many of these things written but will continue to post them from time to time.
HOR's and Other Engines --- Part One
The period from 1932 to 1942 saw a
profound change in the US submarine force. Not without problems.
Not the least of the problems was what engines were the best for the
new 'diesel electric' drive.
This article is an explanation of one
part of the teething problems in selecting the 'proper' engine. For
those of you who have or have access to Freidman's “US Submarines
Through 1945” and Alden's “The Fleet Submarine in the U.S. Navy”
this article will cover ground already well described in those two
books. In addition there is more information from C.C. Wright's
essay published in Warship International.
In the late 1920's the US Navy was
looking at the growth of the submarine forces in England, France and
Japan. The US had a large force but not of modern submarines. New
design concepts included a two fold increase in the size of
submarines which forced new thinking about propulsion systems. If
the submarine grew by a factor of two the required shaft horsepower
necessary to maintain the same speed of the smaller submarine would
necessarily grow by a factor of eight. Larger diesel engines were
not a solution because the engines still had to fit inside the hull
which didn't grow much in diameter so the number of engines would
have to be increased. That involved complex direct drive shafting
problems such as those tried in the early 'fleet submarine' and
'cruiser submarine' designs that followed the 'S-Class'.
The Bureau of Engineering requested
proposals for diesel engines for submarines. This was done at a time
when the diesel generator was coming on line as a motive power in the
railroad industry and was seen to be a viable replacement for the
steam engine. With the advent of this diesel electric drive the
submarine force could get away from the direct drive diesel
propulsion. Coupled with diesel electric drive was the need for a
more sophisticated centrally located control system for the routing
of electrical power from the diesel generators to the motors,
controlling propulsion motor speed and controlling battery usage
including charging.
Initially Winton diesels were seen to
be the best option of the five companies to respond to the request
for proposals. Winton diesels were the first to include high
pressure fuel injection mounted on each cylinder. This simplified
the piping system for the engine making them more reliable. Their
engines were used by the Electro-Motive Company who was involved in
creating electric propulsion for trains replacing steam engines. In
1930 General Motors Corporation purchased both the Winton diesel and
Electro-Motive companies melding them into the Winton Diesel Company.
Eventually the company took the name of the city in which they were
located and became the Cleveland Diesel Company.
Two additional diesel manufacturers
entered the picture also and asked to be considered. These were the
Fairbanks Morse Corporation and Hooven-Owens-Rentschler.
The three diesel engine types selected
to be used by the submarine force were the “V-block” General
Motors, the “opposed piston” Fairbanks Morse and the 'double
acting” Hooven-Owens-Rentschler (HOR) engines. The website of the
Historic Naval Ships Association has the submarine diesel instruction
manual at “ http://archive.hnsa.org/doc/fleetsub/diesel/index.htm" rel="nofollow - http://archive.hnsa.org/doc/fleetsub/diesel/index.htm ”
which contains good explanations of the types of diesels.
The FM engines (FM 1200 HP 38D) were
slated to go into new construction boats (Plunger and Pollack) at the
Navy Yard in Portsmouth, NH. The GM engines (Winton 201) to (Shark,
Tarpon, Perch) at Electric Boat and the HOR engines were to go to
Pompano at Mare Island. As these submarines came on line and were
tested problems came to the fore.
The GM engines smoked excessively which
was important because it gave away the submarine's position while on
the surface. To correct this issue the pistons were changed from
aluminum to iron and the lubricating oil system was changed to
increased capacity. These changes would be expensive. The 201A's
gave disappointing performance on the long patrols being seen in the
Pacific. The 60 day patrols involved longer underway periods than
had be contemplated during peacetime. This meant the engines were
seeing many more hours use between alongside maintenance.
The FM engines were generally not
tested enough to reach a conclusion as to their reliability and it
was felt that they might not be as robust as necessary. Cracks in
the water jacket and burned pistons of the FM engines required
expensive repair parts stockpiles.
Of all the engines, the ones made by
Hooven-Owens-Rentschler (HOR) gave the most problems. A letter from
ComSubPac to the Chief of Bureau of Ships listed the actual problems.
These included: Inaccessibility of components was so bad that
inspections of pistons, oil and fresh water coolers could not be
properly performed. Vibration was such that component piping cracked
after 'a few hundred hours of operation'. Piping runs were poorly
designed and made work on the engines difficult. Lubricating oil
consumption was excessive. The engines required more air than Winton
or FM engines. This meant the engine rooms were wet due to the high
airflow rate in the inductions entraining an excessive amount of salt
spray. Cylinder blocks, being flame hardened were prone to excessive
wear. Fuel consumption was higher than Winton or FM engines. The
bottom line was that the engines were unreliable which in a wartime
situation was intolerable. To correct the problems would take a
complete redesign of the engine then changes to the engines already
in production for submarines, patrol craft and some destroyer
escorts.
End of part one. Stay tuned for the next installment. Maybe next week.
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