268 Glossary
regulatory mark White and orange aid
to navigation that shows controlled areas,
areas of danger, and where boats are not
allowed.
restricted visibility A condition when
vessels are unable to see each other
because of fog, haze, mist, rain, sleet,
snow, or high seas.
right-of-way This term applies to
vessels on the Great Lakes and Western
Rivers. A power-driven vessel in a narrow
channel or fairway proceeding downbound
with a following current shall have
the right-of-way over an upbound vessel.
Vessels crossing rivers shall keep clear of
vessels that are ascending or descending
the river.
risk of collision The skipper and crew
of every vessel must use all available
means appropriate to the prevailing conditions
to determine if risk of collision
exists. If you have any doubt, then the
risk of collision exists and you must take
whatever evasive action is necessary to
avoid collision.
rode Anchor line or chain.
rope Cordage made of natural or synthetic
fibers; can be made of steel wire.
round bottom Round bottom boats
offer a smoother ride through the water
because they have no hard surfaces for
waves to pound against and are resistant
to capsizing. Usually, larger ships such as
freighters and cruise liners have round
bottoms and often have underwater
appendages to help displace water and
improve fuel efficiency.
rudder A flat board or plate hung on
the aft end of a boat and used to steer the
boat.
rudder post The shaft to which a rudder
blade is attached. The tiller or other steering
apparatus is affixed to the other end.
running rigging Running rigging is
composed of the lines used to raise, set,
and trim sails.
S
sailing vessel Any vessel under sail
provided that propelling machinery,
if fitted, is not being used.
sails Provide the boat’s propulsion
through wind-power.
schooner A vessel with two or more
masts rigged fore-and-aft, with the
forward mast being shorter or equal in
height to the aft mast.
scope Ratio of the length of payed out
anchor line (rode) to the height of the
chock above the bottom of the body of
water.
screw See propeller.
sea A system of wind waves that are still
being blown by the wind force that created
them. Usually irregular and choppy,
unlike swell.
seaplane includes any aircraft designed
to maneuver on the water.
seats Typically two seats are built into a
canoe for the paddlers’ comfort.
seaworthy Said of a boat that is in fit
condition to put to sea.
secure To cover openings and make
movable objects fast.
secretary The Secretary of the department
in which the Coast Guard is operating.
Security (Sécurité) The term used to
signify a message concerning the safety of
navigation under international radiotelephone
procedures; the third priority transmission
(pronounced “sea-cur-i-tay”).
semi-displacement hull Combines the
hull features of displacement and planing
hulls. These boats have sufficient power
and a hull design that allows them to rise
partially out of the water.
shackle A U-shaped metal device with
removable pin used to connect a sail, line,
or fitting.
shaft A cylindrical rod. A rotating shaft
is used to transmit power from the engine
to the propeller.
shank The part of an anchor that connects
the flukes to the rode.
sheets Lines used to control sails and
booms.
short blast A blast of about one
second’s duration.
shrouds Wire cables that support the
mast from side to side.
sidelights A green light on the starboard
side and a red light on the port side
each showing an unbroken light over an
arc of the horizon of 112.5 degrees and
so fixed as to show the light from right
ahead to 22.5 degrees abaft the beam
on its respective side. In a vessel of less
than 20 meters in length the sidelights
may be combined in one lantern carried
on the fore and aft centerline of the vessel,
except that on a vessel of less than
12 meters in length the sidelights when
combined in one lantern shall be placed
as nearly as practicable to the fore and aft
centerline of the vessel.
slack 1. Not carrying any load, loose. 2.
To ease or pay out a line.
sloop Single-masted sailboat with the
mast stepped less than 40% of boat length
aft of the bow and setting a mainsail and
normally one triangular headsail.
small stuff Light line, marline, waxed
twine, etc., used for whipping, seizing
and serving.
snub To stop a line running out by taking
a turn around a bitt or cleat.
sole The floor of a boat.
sounding A measured or charted depth
of water, or the measurement of that
depth.
spars Poles that support the sails.
special flashing light A yellow light
flashing at regular intervals of 50 to 70
flashes per minute, placed as far forward
and as nearly as practicable on the fore
and aft centerline of the tow and showing
an unbroken light over an arc of the
horizon of not less than 180 degrees nor
more than 225 degrees and so fixed as
to show the light from right ahead to
abeam and nor more than 22.5 degrees
abaft the beam on either side of the
vessel.
speed Rate of motion.
spinnaker A spinnaker sail flies at the
foremost part of a sailboat with special
rigging and a pole. It usually replaces the
smaller jib as the headsail in downwind
tacks.
stability The ability of a boat to resist
heeling and overturning.
standing part The part of a rope that is
made fast.
stand-on vessel A term, from the
Navigation Rules, used to describe the
vessel that continues its course in the
same direction at the same speed during
a crossing or overtaking situation, unless
a collision appears imminent. Compare
give-way vessel.