L-5 under construction at the Lake yard, Bridgeport, CT., April 30, 1916. She would be launched the next day. The Lake design had the stern end in a flat, horizontal "shovel", with the rudder, stern diving planes, and propeller shafts mounted ventrally under the stern. In an effort to preserve buoyancy while surfaced, portions of the superstructure atop the hull were intended to be watertight. The small round holes on the side were actually for flood port valves for these superstructure buoyancy tanks. The fairwater around the conning tower can be seen in the center. Barely visible on the far left behind the L-5 is an N-class submarine under construction.
Photo courtesy of The US Navy Submarine Force Library & Museum.
The bow of L-5 on the building ways at the Lake yard in Bridgeport, CT., April 30, 1916. The outer shutter doors for two of her four 18-inch torpedo tubes can be seen, just below the typical Lake-style raised bow. One set of three amidships diving planes are visible folded against the hull just above the beginning of the bilge keel. Lake used three sets of amidships diving planes in place of the more common single set of bow diving planes. The amidships planes supposedly enabled level diving without having to take an angle. In practice, it didn't provide a significant safety advantage as claimed, and the Navy didn't like the feature. Above and aft of the diving plane is a circular flood port for the semi-watertight superstructure.
Photo courtesy of The US Navy Submarine Force Library & Museum.
Closeup of the April 30, 1916 photo above showing details of the folded diving plane and the superstructure flood port. The flood port was closed off by a tilting valve disc. The long bilge keel is visible just below the diving plane. The bilge keel is intended to reduced rolling action while on the surface.
Photo courtesy of The US Navy Submarine Force Library & Museum.
L-5 under construction at the Lake yard in Bridgeport, CT., April 30, 1916. This view is from the forward deck looking aft. In the foreground is the oval torpedo loading hatch, with round torpedo room access hatch immediately aft. In the background is the conning tower fairwater, with two rectangular deadlight windows visible. The chariot style bridge fairwater has not yet been installed. There are several wicker fenders strewn about the deck. Just visible on the right in the photo is a N-class submarine under construction.
Photo courtesy of The US Navy Submarine Force Library & Museum.
L-5 under construction at the Lake company yard, Bridgeport, CT., May 23, 1916. The workmen are lowering one of 120 battery cells through the torpedo room hatch. This cell will be part of a 60 cell unit in a well under the torpedo room. Another well with 60 more cells is under the aft end of the control room. These man sized battery cells power the boat while it is submerged. Note the no smoking sign on the right. On the far left the bridge helm station has been added on top of the conning tower and the conning tower hatch can just be seen. The bridge fairwater will be added later. Note the details of the access hatch near where the battery cell is being lowered. It is a simple T-bar that is tightened against the underside of the hatch coaming by the attached handwheel. Later submarines would have a much more substantial and rugged design.
Photo courtesy of The US Navy Submarine Force Library & Museum.
A closeup of the above May 23, 1916 photo. It shows details of the conning tower and the newly installed bridge helm wheel. The conning tower deadlight windows gave a crewman in the conning tower a theoretical ability to see out while submerged, but in practice the view was so limited that it was impractical. Later experience gained during WWII depth charge attacks showed that these small windows were a liability; they could be easily broken by shock damage and flood the conning tower. Boats still in commission during WWII that had deadlights had them removed and plated over.
Photo courtesy of The US Navy Submarine Force Library & Museum.
