Surfacing must be done with caution. The submarine is first brought to periscope depth and a thorough search is made of the surrounding area. When assured that surfacing is safe, the preliminary order, "Stand by to surface," warns the personnel that the signal may be expected. At the sounding of the signal, three blasts of the diving alarm, or the, passing of the word "Surface, Surface, Surface," the various actions necessary are performed.
The bow planes are placed on ten degrees dive and rigged in automatically unless the conning officer gives other instructions. A report, "Bow planes rigged in," is made to the conning officer. Speed is increased to about 6 knots to give maximum lift. Due to the up-angle on the ship, the increased speed makes the inclined surface of the hull effective and the resultant lift raises the ship, The stern planes are used to limit the upangle to about 5 degrees. The up-angle may be increased by blowing the bow buoyancy tank. Blowing the safety tank increases the positive buoyancy. However, this is not usually done. The main ballast tanks are partially blown to surface normally. After surfacing, the high-pressure air is secured and the blow is completed with the low-pressure blowers. Sealing the lower conning tower hatch permits immediate opening of the upper hatch since the relatively small volume of air in the conning tower can be released without danger. This procedure expedites the movement of personnel to the bridge.
When the decks are awash, the conning tower hatch is opened and the commanding officer goes to the bridge. In the meantime all stations, are alert and prepared to dive at once. The safety of the ship demands that nothing interfere with an emergency dive, should it become necessary. When the commanding officer is satisfied with surface conditions, the announcement, "All clear" will indicate that the submarine is to remain on the surface and the remainder of the surfacing routine is carried out.
During this interval, the low-pressure blowers, using air from within the ship, are completing the blowing of the main ballast tanks and reducing the pressure within the hull. Usually the pressure is equalized before the lower conning tower hatch is opened. The engine air induction and hull outboard ventilation valves are opened on orders from the bridge. Propulsion is shifted to the main engines from the batteries. The safety tank is flooded, the low pressure blowers are secured after 15 minutes running, or when the tanks are dry, and normal surface routine is again assumed.