Compass variation and deviation; T-V-M-D-C

Bowditch Ch. 1 §101

Bowditch Ch. 1 §101 — Introduction to Marine Navigation Marine navigation is the art and science of determining a vessel's position and conducting it safely from one point to another. Its four primary methods are dead reckoning, piloting, celestial, and electronic — modern voyages combine all four with electronic navigation as the principal real-time reference and the others as cross-checks.

Bowditch Ch. 1 §102

Bowditch Ch. 1 §102 — Introduction to Marine Navigation Dead reckoning (DR) is the determination of position by applying course steered and distance run from a known starting point. DR accuracy degrades over time and must be confirmed by external fixes whenever possible.

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 §164.78

§ 164.78 § 164.78 Navigation under way: Towing vessels. (a) The owner, master, or operator of each vessel towing shall ensure that each person directing and controlling the movement of the vessel— (1) Understands the arrangement of the tow and the effects of maneuvering on the vessel towing and on the vessel, barge, or object being towed; (2) Can fix the position of the vessel using installed navigational equipment, aids to navigation, geographic reference-points, and hydrographic contours; (3) Does not fix the position of the vessel using buoys alone (Buoys are aids to navigation placed in approximate positions either to alert mariners to hazards to navigation or to indicate the orientation of a channel. They may not maintain exact charted positions, because strong or varying currents…

33 CFR §164.80

§ 164.80 § 164.80 Tests, inspections, and voyage planning. (a) The owner, master, or operator of each towing vessel of less than 1,600 GT shall ensure that the following tests and inspections of gear occur before the vessel embarks on a voyage of more than 24 hours or when each new master or operator assumes command: (1)A test of the steering-gear-control system; a test of the main steering gear from the alternative power supply, if installed; a verification of the rudder-angle indicator relative to the actual position of the rudder; and a visual inspection of the steering gear and its linkage. (2)A test of all installed navigational equipment. (3)Operation of all internal vessel control communications and vessel-control alarms, if installed. (4)Operation of all navigational lights an…

46 CFR §184.402

§ 184.402 § 184.402 Compasses. (a) Except as otherwise provided in this section every vessel must be fitted with a suitable magnetic compass designed for marine use, to be mounted at the primary operating station. (b) The following vessels need not be fitted with a compass: (1) A vessel on a rivers route; (2) A non-self propelled vessel; and (3) A vessel operating on short restricted routes on lakes, bays, and sounds. (c) Except on a vessel limited to daytime operations, the compass must be illuminated.