2. Procedure for Ships Passing a Dredge

1. Visual signals to determine which side to pass on, displayed by a dredge according to Part B of the present Rules, do not indicate that passage for ships around the dredge is clear, but only indicate that the dredge intends that ships pass on one side or the other.

Therefore, all power-driven vessels, in approaching to within 5 cables of an operating dredge, must proceed at dead slow speed (a speed at which the ship does not lose maneuverability) and, irrespective of lights and shapes displayed on the dredge in accordance with present Rules, must sound a prolonged blast (4-6 seconds)—an interrogation concerning the possibility of passing.

2. A dredge, hearing a prolonged blast from an approaching ship, must confirm the side of clear passage or the occupied side with sound signals, according to the following system:

one prolonged blast-proceed to starboard;

- two prolonged blasts-proceed to port;

three prolonged blasts-passage prohibited, stop.

3. Ships receiving an acoustic response signal from a dredge in accordance with the aforementioned system, confirming visual signals, either pass the dredge at dead slow speed, at maximum distance from it, or await clear passage, depending on the meaning of the signal sounded by the dredge.

4. In the absence of a response sound signal from the dredge, the ships must assume that passage is closed on both sides, and must accordingly await clear passage.

5. A dredge must provide safe passage to an approaching vessel in good time. In any case, not less than 3 cables before the vessel approaches, the dredge must be on the appropriate side of the channel, fairway, etc. Otherwise the dredge must sound a blast at this time, indicating passage prohibited.

other.

Vessels passing dredges are prohibited from overtaking or passing each

NOTE: In case two vessels, proceeding on opposite courses, approach a dredge simultaneously, the masters of the two vessels and the dredge must follow the universally accepted rules: the first to pass are vessels proceeding downstream, leaving port or proceeding seaward through the fairway.

Exceptions thereto must be stipulated in local navigation rules.

7. Vessels are prohibited from dragging behind cables, chains and other objects on the bottom while passing a dredge, or holding their anchors in the water while passing a dredge.

8. A dredge may not have two scows simultaneously alongside on the side of clear passage.

9. Scows, tugs, launches and other vessels may not approach a dredge or depart from it from the moment the signal authorizing a ship to pass it is sounded until the vessel has passed the dredge.

10. A dredge not in operation is not permitted in a fairway or channel, etc., where ship maneuvering is difficult.

NOTE: 1) A dredge is considered not to be in operation if her cross-dredging anchors are secured.

2) Persons violating these Rules are subject to prosecution under Art. 75-2 of the Criminal Code of the RSFSR or under appropriate articles of the criminal codes of the Union Republics.

3) Dredges operating under way with a hopper display lights and shapes for vessels engaged in laying or picking up submarine cable, i.e., in accordance with the Rules of the Road, Rule 4, Para. (c).

SECTION 35. RULES FOR SIGNALING FROM LIGHTSHIPS
NOT ON STATION (Appendix 20)

1. If a lightship is not on station, irrespective of whether she is adrift or proceeding to her destination, she does not display the lights stipulated for her, and does not sound fog signals.

by day-two large black balls: one in the bow and the other in the stern of the vessel;

at night-two red lights: one in the bow and the other in the stern of the vessel.

Daylight distinguishing signals are hauled down, if possible.

If circumstances do not permit use of the aforementioned daylight signals, or if these signals are distinguishing for a given lightship, then red flags are hoisted in lieu of black balls.

3. Moreover, as an additional precaution, a lightship adrift:

by day-hoists the signal "PC" using the International Code of Signals, meaning: "I am not on station";

by night-burns red and white flares simultaneously, at least every quarter of an hour.

If the circumstances do not permit use of flares, they are replaced with the simultaneous display of red and white lights.

4. A lightship proceeding to her destination displays lights and sounds fog signals established for vessels under way; moreover, if the lightship proceeds under her own power, she displays the daylight signals indicated in Para. 2.

SECTION 36. SPECIAL WARNING SIGNALS IN PORTS OF THE USSR

Signals concerning time of arrival of anticipated weather, high and low tide, storms and heavy winds, height of waves and ship movements in roadsteads are indicated in Appendices 23-27.

CHAPTER V

NAVIGATION

SECTION 37. MEASUREMENTS, CORRECTION AND
PLOTTING THEIR RESULTS

1. Self-control in Performing Measurements and Calculations

In performing all measurements and calculations, constant self-control must be maintained:

1) making a measurement (taking an instrument reading), perform these actions repeatedly in order to be sure there is no serious error in the observation and reading;

2) check measurements made with one instrument with another (course by the master compass-by the course according to another course indicator; distance run according to the log-distance calculated from the speed and time; ship's position determined by one method-test observation made using another method, etc.);

3) check the correctness of calculations by repeating them, ordinarily using another method;

4) having discovered an error which could affect navigational safety, and however it might have been permitted, it must be immediately reported to the Commanding Officer of the ship, and measures taken to prevent its possible dangerous consequences.

2. Course Indication

Compass and directional gyro corrections. Gyrocompass correction is usually continuous, but due to rolling, course alterations or change in speed, and the influence of other factors, it may deviate from its mean value. In course correction, the mean value of the compass correction is found, ordinarily, on the basis of prolonged (not less than 2 hours) observations. In correcting compass bearing, the instantaneous value of the gyrocompass correction is used, determined immediately before a bearing is taken, or if this is impossible, the mean gyrocompass correction is used.

The magnetic compass correction

AMC = d + 8,

(70)

Magnetic declination d is obtained from the chart in the area of navigation of the vessel. It must be adjusted to the navigation year (the annual variation in declination is also indicated on the chart).

Example: The magnetic declination from the chart is 7°.4W, adjusted to 1962; the annual decrease is 0°.12. Adjusting the declination to 1967:

d = (7°.40°.12-5)=-6°.8.

Deviation & varies with a change in the ship's course. It is obtained from the deviation table (for each magnetic compass) according to the compass course, or in calculating the compass course-from the magnetic course. With the passage of time, and also after submergence of a submarine to a considerable depth, electric welding near a compass and artillery firing; with a considerable change in the latitude of the area of navigation, etc., deviation can vary considerably and must be determined repeatedly.

The directional gyro correction

AGA AC+ at,

(71)

where AC correction of the compass with which the directional gyro was matched, at the moment of matching;

a directional gyro drift rate;

t time interval after matching.

The rate of directional gyro drift can be determined by determining its correction twice, with time interval t between them:

Calculating true course and true bearing from measured values (Fig. 61):

TC CC + AC;

TBCB AC;

TB TC + RB.

(72)

(73)

(74)

(75)

In plotting on the chart, only the true values (true course, true bearing) have

to be used. In using Eq. (75), the relative bearing starboard is considered positive, and port, negative.

Calculating compass course and compass bearing from values obtained from the chart (Fig. 61):

In order to calculate the compass course from the magnetic compass, first we must calculate the magnetic course:

from the magnetic course obtain the deviation from the table and calculate the compass course:

CC MC 8.

(80)

Determining compass correction.

a) From the bearing of the leading line, the true direction of which is known, or of a celestial body (its dead-reckoned azimuth at the moment the bearing is taken is assumed to be the true bearing), or of a distant object, the true bearing of which is known (taken from the chart from a precisely known ship position):