Danger bearings and danger circles

Bowditch Ch. 7 §703

Bowditch Ch. 7 §703 — Bearings and Lines of Position Bearings to a single object can produce a running fix when the relative bearing changes substantially. The 'doubling-the-angle' technique uses two relative bearings; the distance run between them equals the distance to the object at the second bearing.

Bowditch Ch. 7 §704

Bowditch Ch. 7 §704 — Bearings and Lines of Position Compass bearings of an approaching vessel are the canonical method of detecting risk of collision. If the bearing remains constant and the range is decreasing (CBDR), risk of collision exists.

33 CFR §164.35

§ 164.35 § 164.35 Equipment: All vessels. Each vessel must have the following: (a) A marine radar system for surface navigation. (b) An illuminated magnetic steering compass, mounted in a binnacle, that can be read at the vessel's main steering stand. (c) A current magnetic compass deviation table or graph or compass comparison record for the steering compass, in the wheelhouse. (d) A gyrocompass. (e) An illuminated repeater for the gyrocompass required by paragraph (d) of this section that is at the main steering stand, unless that gyrocompass is illuminated and is at the main steering stand. (f) An illuminated rudder angle indicator in the wheelhouse. (g) The following maneuvering information prominently displayed on a fact sheet in the wheelhouse: (1) A turning circle diagram t…

33 CFR §164.38

§ 164.38 § 164.38 Automatic radar plotting aids (ARPA). (a) The following definitions are used in this section— means material in any quantity that is shipped, stored, or handled without benefit of package, label, mark or count and carried in integral or fixed independent tanks. means a stage of construction where— (1) The keel is laid; (2) Construction identifiable with a specific ship begins; or (3) Assembly of that ship has commenced comprising at least 50 tons or 1 percent of the estimated mass of all structural material, whichever is less. means— (1) A flammable liquid as defined in 46 CFR 30.10-22 or a combustible liquid as defined in 46 CFR 30.10-15; (2) A material listed in table 151.05 of 46 CFR 151.05, table 1 of 46 CFR 153, or table 4 of 46 CFR Part 154; or (3) A liqui…

33 CFR §83.07

§ 83.07 § 83.07 Risk of collision (Rule 7). (a) Every vessel shall use all available means appropriate to the prevailing circumstances and conditions to determine if risk of collision exists. If there is any doubt such risk shall be deemed to exist. (b) Proper use shall be made of radar equipment if fitted and operational, including long-range scanning to obtain early warning of risk of collision and radar plotting or equivalent systematic observation of detected objects. (c) Assumptions shall not be made on the basis of scanty information, especially scanty radar information. (d) In determining if risk of collision exists the following considerations shall be among those taken into account: (i) Such risk shall be deemed to exist if the compass bearing of an approaching vessel does no…

33 CFR §83.19

§ 83.19 § 83.19 Conduct of vessels in restricted visibility (Rule 19). (a) This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility. (b) Every vessel shall proceed at a safe speed adapted to the prevailing circumstances and conditions of restricted visibility. A power-driven vessel shall have her engines ready for immediate maneuver. (c) Every vessel shall have due regard to the prevailing circumstances and conditions of restricted visibility when complying with Rules 4 through 10 (§§ 83.04 through 83.10). (d) A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, she shall take avoiding action in ample time, provi…