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23. The officer of the watch looks after the anchor chain and its scope, which must always depend on anchorage and weather conditions, as well as mooring lines and clearing away of the second anchor.

If the wind freshens, he orders a wind measurement report every hour or 30 minutes and, according to circumstances, takes measures to recover launches and boats, or directs them to a sheltered anchorage.

The officer of the watch shall pay particular attention to the drift of the ship, utilizing for this purpose a ballast pig cast overboard, natural range lines and landmarks.

24. The officer of the watch is responsible for readiness of the ship to receive supply ships at the appropriate time (stowing ladders, davits and cranes) and rapid recovery of mooring lines, and must organize taking on of supplies in such a way that the supply ship is alongside for a minimum period of time.

25. Before testing the engines, the officer of the watch takes precautionary measures with respect to the boats (launches) and the lines behind the stern, and looks after the mooring lines and the anchor chain. With the knowledge of the Executive Officer, making certain that the engine order telegraph is ready, he gives the order to begin test revolutions.

26. The officer of the watch shall be on the main deck during anchorage, preferably on the quarterdeck or at the accommodation ladders. In fresh weather when the ship is anchored with steam up, when the main engines are running, and in other situations requiring personal supervision of the surrounding area, and on submarines, the officer of the watch shall be on the bridge.

27. In addition to the aforementioned (Para. 9), when the ship is anchored, the offgoing officer of the watch shall provide information concerning:

a) readiness of the ship to get under way;
b) trim of a submarine and its readiness to submerge;

c) scope of anchor chain in the hawse (moored to a buoy by a hawser or to a pier);

d) clearing away of the second anchor;
e) depth, bottom and current;

f) crew members absent, as well as the presence of noncrew members on board;

g) launches and boats, both away from the ship and alongside;
h) disposition of ships anchored in the harbor, location of the SOPA;

i) conventional alarm signals. 28. The officer of the watch controls the movement of all personnel and articles to and from the ship.

29. In receiving launches bearing senior officers, the officer of the watch occupies the position indicated in Fig. 1.

In receiving launches (boats) carrying NCOs and seamen, the officer of the watch remains at the top of the ladder until the last man leaves the launch (boat).

30. Whenever personnel disembark from the ship, the officer of the watch shall not permit the men to congregate at the gangway. Before beginning a landing or shore leave, departing NCOs and seamen must be in formation.

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1. If the official is met (or accompanied) only by the watch officer or the Officer of the

Day, he occupies the position of the Commanding Officer of the ship. Otherwise the

arrival (departure) procedure remains the same. 2. The numbers adjacent to the designations of officials indicate their position at various

moments during arrival. The absence of numbers with designations indicates that these individuals do not change position during the arrival (or departure).

Fig. 1. Sample sketches showing location of watch personnel

during arrival and departure of senior officers.

As the launch (boat) approaches the ladder, the officer of the watch directs the seamen and NCOs to embark first, followed by the officers, insuring that the boat is not loaded beyond its capacity.

The officer of the watch shall station himself at the top of the ladder while the men are boarding the launches (boats) and shall remain until they pull away from alongside.

SECTION 4. ORGANIZATION OF THE WATCH

31. The officer of the watch is the officer on watch in charge of the ship.

Departmental watches are under the direction of the respective heads, with the exception of the watches referred to in Para. 2a, which are under the direction of the officer of the watch.

32. A normal watch is 4 hours. Depending on the situation, watches at individual stations can be decreased to one hour or increased to not more than 6 hours by order of the Commanding Officer. As a rule, the normal watch for helmsmen and lookouts is 2 hours.

33. Fifteen minutes before the watch is relieved under way, the officer of the watch or, in port, the Officer of the Day, if there is no officer of the watch, calls the watch and announces the uniform of the day.

34. When the ship is at anchor or moored, by command from the watch the incoming watch falls in at the prescribed time for muster.

35. Muster of the watch routine is the responsibility of the officer of the watch (Officer of the Day).

36. Ten minutes before relieving the watch the officer of the watch (Officer of the Day) gives the command “Relieve the watch," and five minutes before relieving the watch gives the command “Attention! Begin muster," then begins to muster the watch.

37. The watch muster at anchor is accomplished in the following order: the incoming watch falls in for roll call and is checked to make sure they are familiar with their duties; after a report is received from the engineering department duty officer on the results of his inspection, the officer of the watch (Officer of the Day) gives the command “Proceed to your stations,” whereupon members of the watch proceed to their stations to relieve the watch.

Upon receipt of reports from those in charge of watch stations and the engineering department duty officer on the incoming watch, the officer of the watch gives the command “Watch below dismissed,” whereupon members of the offgoing watch leave their stations and the new watch comes on.

38. The watch muster under way is accomplished in the following sequence: the oncoming engineering officer of the watch and officer on duty below the decks on a surface vessel muster the engineering department watch, duty watches in the compartments and the underway guard at stations established by order of the Commanding Officer. There is no watch muster on submarines.

According to the condition of readiness sounded, when the officer of the watch gives the command “Relieve the watch,” incoming watch mans assigned watch stations and assumes the duty, reports to the command post of the department by telephone on the status of stations and, on submarines, to the control room watch officer. They begin the watch once approval is obtained.

On a submarine, after the oncoming watch takes over, the engineering officer of the watch makes the rounds of the compartments, checks to insure that the oncoming watch has manned its stations and is standing the watch properly. He makes his report to the officer of the watch.

CHAPTER II

SUBMARINES

SECTION 5. BUOYANCY OF A SUBMARINE

1. Trim of a Submarine

The trim of a submarine is her position relative to a calm water surface. The surface position of a submarine is characterized by the parameters of her trim overall: draft (T), heel (0) and trim (V).

If the fore-and-aft line and the plane of the midship frame are vertical, the submarine is upright and on an even keel. In this case, the waterline is parallel to the reference plane, and its position is determined by a single draft 7, whereby ♡ = 0 = 0. If the fore-and-aft line and the plane of the midship frame are inclined, the submarine lies with a heel and trim.

The trim of a surfaced submarine is determined by the draft marks, located on the outer hull of the submarine on each side at the bow and stern, usually equidistant from the midship frame.

2. Center of Gravity and Center of Buoyancy

а

Buoyancy is the ability of a submarine to navigate on the surface along the designated waterline, and submerged at depths not exceeding the maximum operating depth, while carrying all loads according to specification.

A submerged submarine is subjected to pressure from all sides. The pressure forces are perpendicular to the pressure hull surface and proportional to the submarine's submergence depth H. All horizontal components of the normal forces tend to compress the submarine, whereas the parallel vertical components create a resultant upward force D, equal to the weight of the water in the volume of the submerged body.

Force D is called the force of buoyancy, and its point of application Co is called the center of buoyancy (Fig. 2).

Moreover, the force of gravity P(weight of the submarine), acting vertically downward, also acts on the submarine.

The force of buoyancy D and force of gravity Plie on the same vertical. The resultant of these two forces is equal to their difference and is in the direction of the greater force.

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In the first case, when the weight P of the submarine is greater than the force of buoyancy D, their resultant is downward. The submarine will dive.

In the second case, when the weight P of the submarine is equal to the force of buoyancy D, the resultant is equal to zero and the submarine will maintain equilibrium.

In the third case, when the weight P of the submarine is less than the force of buoyancy D, their resultant is upward and the submarine begins to climb. It will continue to climb while forces P and D are unequal, and will stop only after part of the volume of the submarine extends above the surface of the water and the force of buoyancy decreases to the weight of the submarine, i.e., when force D becomes equal to force P.

The center of gravity Go changes its position only if there is a change in the weight of the load or if it is displaced from one position to another along the length or breadth of the submarine.

The center of buoyancy Co is the center of gravity of the volume of water displaced by the submerged section of the submarine. Its position varies depending on the shape and size of the submerged volume of the submarine.

3. Weight and Volume Displacement

The submerged volume of a submarine V (in m3) serves as a measure of buoyancy and is called volume displacement. The weight of the water in volume V is called weight displacement D.

Weight Displacement

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