An engineering casualty may affect the rota-tion of the main shaft and cause further damage. In such cases, the main shaft should be locked until necessary repairs can be made, since, except at very low speeds, movement of the ship through the water will cause the shaft to turn, whether the ship is proceeding by its own power or being towed.

There are no standard procedures for locking a main shaft which are applicable to all types of diesel-driven ships. On ships that have main reduction gears, shaft locking by means of the jacking gear is permissible, provided that the jack-ing gear has been designed for this purpose (as indicated, by the manufacturers instructions) or when such action is approved by NAVSEA. Some ships are provided with brakes that are used for holding the shaft stationary. When no provisions have been made for locking the main shaft, it is usually possible to arrange a jury rig (preferably at a flanged coupling) which will hold the shaft. As a precautionary measure, jury rigs should be made in advance of an actual need for locking a shaft. On diesel-electric drive ships, no attempt should be made to hold the shaft stationary by energizing the electrical propulsion circuits.

EMERGENCY PROCEDURES

Under certain circumstances you may receive the order to light off additional engines. When time will not permit following normal routine pro-cedures, emergency procedures may have to be used. Since procedures differ, depending on the installation, you must be familiar with the pro-cedures established for your ship.

These emergency procedures are listed in the Engineering Casualty Control Manual for your ship. They are issued by the type commander. Upon receipt, manuals are modified to fit the in-dividual installation. It is the responsibility of your ships engineer officer to establish the step-by-step emergency procedures and the necessary checklists.

ENGINEROOM CASUALTIES

The type commander for each class ship for-mulates the engineering casualty procedures which are applicable to a specific type of engineering plant.

In the event of a casualty to a component of the propulsion plant, the principal objective is the prevention of additional or major casualties. Where practicable, the propulsion plant must be kept in operation by means of standby pumps, auxiliary machinery, and piping systems. The im-portant action to be taken is to prevent minor casualties from becoming major casualties, even if it means suspending the operation of the pro-pulsion plant. It is better to stop the main engines for a few minutes than to risk putting them com-pletely out of commission.

When a casualty occurs, notify immediately the EOOW or the petty officer of the watch, who will in turn notify the OOD and the engineer of-ficer. Main engine control must keep the bridge informed as to the nature of the casualty, the ships ability to answer bells, the maximum speed available, and the probable duration of the casualty.