2008 REED’s East Coast Edition - Planning
Lubber line Line on the inside of a compass bowl indicating the ship’s heading.
MAKE To attain; i.e., to “make harbor.” To “make fast” is to secure. Tides that “make” increase. To
“make sail” is to set sail.
Mean High
Water (MHW) A tidal datum. The arithmetic mean of the high-water heights observed over a specific 19-year
Metonic cycle (the National Tidal Datum Epoch).
Mean Higher
High Water
(MHHW) A tidal datum. The arithmetic mean of the higher high-water heights of a mixed tide observed
over a specific 19-year Metonic cycle (the National Tidal Datum Epoch). Only the higher high
water of each pair of high waters, or the only high water of a tidal day is included in the mean.
Mean Higher
High Water Line
(MHHWL) The intersection of the land with the water surface at the elevation of mean higher high water.
Mean Low
Water (MLW) A tidal datum. The arithmetic mean of the low-water heights observed over a specific l9-year
Metonic cycle (the National Tidal Datum Epoch).
Mean Lower
Low Water
(MLLW) A tidal datum. The arithmetic mean of the lower low-water heights of a mixed tide observed
over a specific 19-year Metonic cycle (the National Tidal Datum Epoch). Only the lower low water
of each pair of low waters, or the only low water of a tidal day, is included in the mean.
Mean Range
of Tide (Mn) The difference in height between mean high water and mean low water.
Mean Sea
Level (MSL) A tidal datum. The arithmetic mean of hourly water elevations observed over a specific l9-year
Metonic cycle (the National Tidal Datum Epoch).
Mean Tide
Level (MTL) Also called half-tide level. A tidal datum midway between mean high water and mean low water.
Midships Order to the helmsman to put the rudder fore and aft.
Mixed Tide Type of tide with a large inequality in the high- and/or low-water heights, with two high waters
and two low waters usually occurring each tidal day.
Moor To moor is to lie with two anchors down. Vessels are said to moor to a dock when well made fast
with several lines.
NEAP TIDES
/Currents Tides of decreased range or tidal currents of decreased speed occurring semimonthly as the
result of the Moon being in quadrature.
Neaped A grounded ship is said to be “neaped” when the tide does not rise high enough to float her.
OCCULTING Navigation light with duration of light more than dark.
Offing Distance from land.
PAy OUT To ease a chain or rope.
Perigean
Tides or
Tidal Currents Tides of increased range or tidal currents of increased speed occurring monthly as the result of
the Moon being in perigee or nearest the Earth.
Pitching A ship’s movement in a seaway that lifts and lowers the bow and stern.
Pooped A vessel is said to have been “pooped” when a heavy sea comes inboard over the stern.
Port The left side of a vessel looking forward.
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