The massive funnels on the aircraft carriers USS Lexington (CV-2) and USS Saratoga (CV-3) were a unique design feature stemming from their origins as battlecruisers and the need to accommodate their powerful propulsion systems. These "ginormous" funnels, also called uptakes, served specific engineering and operational purposes:
1. Origin as Converted Battlecruisers
The Lexington and Saratoga were originally planned as Lexington-class battlecruisers under the 1916 naval program. When the Washington Naval Treaty of 1922 limited the construction of capital ships, the two ships were converted into aircraft carriers instead.
Massive Powerplant:
The original battlecruiser design required extremely powerful engines to achieve speeds exceeding 33 knots. This necessitated a vast propulsion system, including 16 boilers generating over 180,000 shaft horsepower. These boilers produced enormous amounts of exhaust gases, requiring large funnels to vent them effectively.
Battlecruiser Legacy:
The conversion retained much of the battlecruiser machinery, including the boiler configuration, which influenced the need for oversized uptakes.
2. Funnel Arrangement and Aircraft Operations
Aircraft carriers need to keep their flight decks as clear as possible to facilitate air operations. This requirement led to innovative funnel designs:
Funnel Consolidation:
Instead of multiple smaller funnels placed along the ship’s length (as seen on earlier ships), the Lexington-class carriers consolidated their uptakes into two large funnels on the starboard side. This arrangement minimized obstructions on the flight deck and allowed for more efficient aircraft operations.
Angled Design:
The funnels were slanted outward to direct hot exhaust gases and smoke away from the flight deck, reducing the risk of obscuring the vision of pilots or interfering with aircraft operations.
3. Cooling and Ventilation
The size of the funnels also helped dissipate heat from the boilers and ensure proper ventilation. Efficient exhaust management was critical to preventing heat buildup in the ship’s engine rooms, which could compromise both performance and crew safety.
4. Aesthetic and Tactical Consequences
The large funnels gave the Lexington and Saratoga a distinct appearance, but they also made the ships more visually prominent, potentially increasing their visibility to enemy forces. However, the advantages in operational efficiency and functionality outweighed this drawback, especially given their roles as key early aircraft carriers for the U.S. Navy.