“Pancakes the U-Boats Can’t Stomach.” Double-page ad from General Motors in “The Saturday Evening Post,” 1943.
“. . . one of the Navy’s most useful helpers in fighting the U-boats is a recently perfected Diesel engine called a ‘pancake’ because its cylinders are stacked one above the other. Combined with GM-developed controllable pitch propellers, this engine has made possible a new-type subchaser with more speed, wider range, increased maneuverability – and therefore greater effectiveness. . .” [From the ad copy]
This WWII-era ad highlights a significant leap in naval engineering. While General Motors’ marketing language focused on the "pancake" moniker, the combination of the GM 16-184A Diesel engine and controllable pitch propellers fundamentally changed the performance of subchasers (specifically the PC-461 and SC classes). The engine’s vertical design saved 80% in weight, allowing for more weaponry and fuel, and it occupied only one-third the space of traditional diesels. This allowed subchasers to be faster with more range without increasing the ship’s overall size.
The controllable pitch propeller was the "secret sauce" for effectiveness against U-boats. Unlike standard propellers, these allowed the ship to change direction (forward to reverse) or speed almost instantly by tilting the propeller blades rather than waiting for the engine to change RPMs. This allowed subchasers to stay directly over a submerged U-boat during depth charge runs, a task that required precise, slow-speed handling that older engines struggled to maintain.
By optimizing the power-to-weight ratio, these subchasers could reach speeds of approximately 20–22 knots, allowing them to outrun surfaced U-boats and close the distance quickly once a sonar contact was made. Because the engines were so efficient and light, the ships could carry enough fuel to escort convoys across vast stretches of the Atlantic, whereas previous smaller craft were often tethered to coastal operations. The ship’s compact size also enabled its mass production, the “splinter fleet” that patrolled the coasts.
[Source: Google Gemini]
“Pancakes the U-Boats Can’t Stomach.” Double-page ad from General Motors in “The Saturday Evening Post,” 1943.
“. . . one of the Navy’s most useful helpers in fighting the U-boats is a recently perfected Diesel engine called a ‘pancake’ because its cylinders are stacked one above the other. Combined with GM-developed controllable pitch propellers, this engine has made possible a new-type subchaser with more speed, wider range, increased maneuverability – and therefore greater effectiveness. . .” [From the ad copy]
This WWII-era ad highlights a significant leap in naval engineering. While General Motors’ marketing language focused on the "pancake" moniker, the combination of the GM 16-184A Diesel engine and controllable pitch propellers fundamentally changed the performance of subchasers (specifically the PC-461 and SC classes). The engine’s vertical design saved 80% in weight, allowing for more weaponry and fuel, and it occupied only one-third the space of traditional diesels. This allowed subchasers to be faster with more range without increasing the ship’s overall size.
The controllable pitch propeller was the "secret sauce" for effectiveness against U-boats. Unlike standard propellers, these allowed the ship to change direction (forward to reverse) or speed almost instantly by tilting the propeller blades rather than waiting for the engine to change RPMs. This allowed subchasers to stay directly over a submerged U-boat during depth charge runs, a task that required precise, slow-speed handling that older engines struggled to maintain.
By optimizing the power-to-weight ratio, these subchasers could reach speeds of approximately 20–22 knots, allowing them to outrun surfaced U-boats and close the distance quickly once a sonar contact was made. Because the engines were so efficient and light, the ships could carry enough fuel to escort convoys across vast stretches of the Atlantic, whereas previous smaller craft were often tethered to coastal operations. The ship’s compact size also enabled its mass production, the “splinter fleet” that patrolled the coasts.
[Source: Google Gemini]