Glossary
15.4
Davit: A device that projects beyond the side of
the boat to raise objects from the water.
Typically a single davit is used on the bow
of a vessel to raise an anchor, and a pair
are used on the side or stern of the vessel
to raise a dinghy.
Dead
ahead:
A position directly in front of the vessel.
Dead
reckon-
ing:
A method of determining position by mak-
ing an educated guess based on last
known position, speed and currents.
Dead run: Running with the wind blowing exactly aft,
in line with the center-line.
Deck-
head:
The underside of the deck, viewed from
below (the ceiling).
Depth
sounder:
An instrument that uses sound waves to
measure the distance to the seafloor.
Deviation: The difference between the direction
indicated by the compass needle and
the magnetic meridian; caused by object
aboard.
Displace-
ment:
The weight of a boat measured as a the
weight of the amount of water it displaces.
A boat displaces an amount of water equal
to the weight of the boat, so the boat’s dis-
placement and weight are identical.
Displace-
ment
speed:
Also hull speed. The theoretical speed
that a boat can travel without planing,
based on the shape of its hull. This speed
is 1.34 times the length of a boat at its
waterline. Since most monohull sailboats
cannot exceed their hull speed, longer
boats are faster.
Distance
made
good:
The distance traveled after correction for
current, leeway and other errors that may
not have been included in the original dis-
tance measurement.
Down-
haul:
A rope fitted to pull down a sail or spar.
Down-
wind:
In the direction the wind is blowing.
Draft: The vertical distance from the waterline to
the lowest point of the keel.
Drag: 1, an anchor drags when it fails to hole;
2, the force of wind on the sails, or water
on the hull, which impedes the boat’s
progress.
Drift: 1, to float with the current or wind; 2, US
the speed of a current (rate UK); 3, UK:
the distance a boat is carried by a current
in a given time.
Drogue: A sea anchor put over the stern of a boat
or life raft to retard drift.
Drop
keel:
A retractable keel which can be drawn into
the hull, when entering shallow waters
and recovering on to a trailer.
Echo-
sounder:
An electrical depth sounder that uses
sound echoes to determine water depth.
It does so by timing how long it takes a
sound pulse to leave the instrument travel
to the seafloor and return to the receiver
on the ship.
Eye of the
wind:
Direction from which the true wind blows.
Fair: Well-faired line or surface is smoother
with no bumps, hollows or abrupt changes
in directions.
Fairlead: A fitting through which a line is run to alter
the lead of the line.
Fall off: Also bear away or bear off. A boat falls
off the wind when it points its bow farther
from the eye of the wind. The opposite of
heading up.
Fathom: The measurement used for depths of
water and lengths or rope. 1 fathom = 6
ft. or 1.83m.
Fetch: The distance that wind and seas (waves)
can travel toward land without being
blocked. In areas without obstructions the
wind and seas can build to great strength,
but in areas such as sheltered coves and
harbors the wind and seas can be quite
calm.
Fid: A tapered tool used for splicing heavy
rope and for sail-making, often hollow.
Fiddle: A raised border for a cabin table, chart
table etc., to prevent objects falling off
when the boat heels.
Fix: The position of the vessel as plotted from
two or more position lines.
Flotsam: Debris floating on the water surface.
Following
sea:
Sea with waves approaching from the
stern of the boat.
Fore: Toward the bow (front) of the vessel.
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