266 Glossary
cartridge. They also inflate orally with an
inflation tube that allows you to use your
own breath to inflate the vest. The tube
also deflates the vest.
inherently buoyant PFDs Inherently
buoyant PFDs have buoyant material
built in, usually foam or kapok. They are
the traditional rugged, low-maintenance
life preservers that are available in adult
and child sizes.
inland rules Inland Navigational Rules
and the annexes thereto, which govern
the conduct of vessels and specify the
lights, shapes, and sound signals that
apply on inland waters; and
inland waters The navigable waters of
the United States shoreward of the navigational
demarcation line dividing the
high seas from harbors, rivers and other
inland waters of the United States and the
waters of the Great Lakes on the United
States side of the International Boundary.
internal combustion Burning of fuel
within an enclosed space.
International Code A Flag. When
vessels are engaged in diving with divers
attached to the vessel, you must display a
rigid blue and white International Code
A flag.
international dateline (IDL) The
boundary between the - 12 and + 12 time
zones, corresponding approximately with
180th meridian.
international regulations International
Regulations for Preventing Collisions at
Sea, 1972, including annexes currently in
force for the United States.
J
jet drive Jet drives use an impeller
mounted in a shaft to pull water in from
under the hull and propel it rearward to
provide thrust. The nozzle on the drive is
turned to steer the boat.
jib Triangular sail set on a stay forward
of the mast.
K
kayak A small paddle boat that usually
has symmetrical hulls with pointed bowlike
structures at each end; enclosed on
top, except for an opening for the paddler.
kedge 1. Move boat by pulling it up to
its anchor. 2. Type of anchor.
keel Main centerline structural member
(backbone) of a boat. Also, downward
extension of hull to increase lateral resistance
and stability.
ketch A two-masted sailboat with the
after mast stepped forward of the rudder
post.
knot 1. General term for securing a line
to an object, another line, or itself. 2. Unit
of speed of one nautical mile per hour.
L
laid Three-strand laid rope has tiers
of fibers that are twisted in groups of
three, usually in a clockwise direction;
then those twisted fibers are themselves
twisted in groups of three, and so on until
the rope is built up to its final size.
lanyard Short line used as a handle or
to secure an object.
lanyard cut-off switch When fastened
to your wrist if you fall off your personal
watercraft (PWC), it will stop the engine.
latitude Latitude is an angular distance
from the equator (north or south),
expressed degrees from 0 to 90. The
equator is 0 degrees and the poles are 90
degrees The horizontal lines shown running
east-to-west on charts are latitude
lines.
lay 1. To lay a mark is to be able to
reach it in a single tack, close-hauled. 2.
The lay of a line is the direction in which
its strands are twisted.
lee (lee side) Side away or opposite that
from which the wind blows. Also, area
sheltered from the wind.
length overall (LOA) The most common
term used to describe the size of a
boat. It is measured from the forward
part of the bow to the after part of the
stern. It does not include attachments
that are not part of the hull, although
bow pulpits and swim platforms become
part of the overall length of a boat.
lifeline When referring to PWCs, it’s
the lanyard cut-off switch. In general, a
lifeline is a rope thrown to a person who
is in danger of drowning.
light lists Light lists describe all lights,
buoys, and beacons maintained in the
navigable waters of the United States.
lightning A visible electrical discharge,
generally produced during a thunderstorm.
line When aboard a boat, rope is called
a line.
line of sight Line of direct visual observation
from one point to another.
locker A storage or stowage compartment.
log 1. Instrument to measure distance
or speed through the water. 2. A book in
which all matters pertaining to a vessel’s
navigation are recorded.
longitude Longitude is the distance east
or west of the prime meridian (0 to 180
degrees). Longitude lines are the vertical
lines shown running north-to-south on
charts. One degree is 60 nautical miles.
M
mainmast The tallest mast on a twomasted
sailing vessel.
mainsail Boat’s principal sail, set aft of
mainmast, (pronounced “mains’el”).
marlinespike A pointed steel tool used
in splicing to open the strands of a rope
or cable.
marlinespike seamanship General
knowledge of knots, bends, hitches,
splices, and care of lines (rope).
mast 1. A vertical spar on a sailboat,
on which sails may be set. 2. A vertical
spar on a powerboat, from which may be
flown a steadying sail or flags and burgees,
and which can be used with a boom
to lift gear.
masthead The top of the mast.
masthead light A white light placed
over the fore and aft centerline of the
vessel showing an unbroken light over
an arc of the horizon of 225 degrees and
so fixed as to show the light from right
ahead to 22.5 degrees abaft the beam on
either side of the vessel, except that on a
vessel of less than 12 meters in length the
masthead light shall be placed as nearly
as practicable to the fore and aft centerline
of the vessel.
Maximum Capacities Label Required
on boats less than 20 feet in length show