 | Term | Definition |
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2 Steps in navigation |
Voyage Planning and Underway Navigation |
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4 Steps in voyage planning |
Assemble materials; formulate voyage options; evaluate the alternatives; select best plan and prepare float plan; check vessel; weigh anchor |
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Reference Materials Needed |
up-to-date appr.scale charts, light list, cruising guides, tide and current tables |
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Float Plan |
describes route and ETA including vessel description and # of people |
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Bolt Holes |
safe places to anchor along a course |
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DR plot |
Tactical dead reckongin plot |
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Dead Reckoning |
Process of predicting the future position of a vessel from knowledge of its present position |
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Fixes |
points in time when the vessel's position is accurately determined |
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3 methods of fixes |
Visual observation of range/bearing/ATON's; electronic; celestial |
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Reality or plausibility check |
Comparison of fix to DR position |
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2 current terms |
set and drift |
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set |
direction of the current |
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drift |
speed of the current |
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Seaman's eye |
navigating from experience in good conditions |
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Oblate spheroid |
earth's shape - flattened at the poles |
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6,880 nautical miles |
diameter of the earth |
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21,614 nautical miles |
circumference of the earth @ the equator |
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Pn and Ps |
geographic north and south poles |
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shortest distance between 2 points |
pass through the great circle |
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small circles |
doesn't pass through earth's center; parallels |
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Latitude |
measure n or s of the equator 0-90 degrees |
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Longitude |
measure e or w of prime meridian (greenwich meridian) 0-180 |
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Parallels |
lines of L or Lat |
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Meridians |
lines of Lo or |
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References to direction 3 |
true north, magnetic north, ship's heading |
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Rhumb line |
spiral around the earth - when each meridian is passed @ the same angle |
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Loxodrome |
same as rhumb line |
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Magnetic meridians |
Drive variation |
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Magnetic variation |
Difference between ghe geographic and magnetic meridians |
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Bearing |
Relationship of object to boat |
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Reciprocal bearing |
Relationship of boat to object |
| Add or remove terms from this set |
