FLOATS-ON-SKIDS —A type of
helicopter float design where the
floats sit on top of the fully func-
tional skids. During water opera-
tions, the floats support the weight
of the aircraft, and on hard surfaces
the skids support the weight of the
aircraft.
FLYING BOAT
—A type of sea-
plane in which the crew, passengers,
and cargo are carried inside a
fuselage that is designed to
support the seaplane on the
water. Also called a hull seaplane.
GLASSY W ATER
—A calm water
surface with no distinguishable
surface features, with a glassy or
mirror like appearance. Glassy
water can deceive a pilot’s depth
perception.
HEIGHT-TO-LENGTH
RATIO
—The ratio between the
height of a swell to the length
between two successive crests
(swell length).
HYDRODYNAMIC FORCES
—
Forces relating to the motion of
fluids and the effects of fluids
acting on solid bodies in motion
relative to them.
HYDRODYNAMIC LIFT
—For
seaplanes, the upward force gener-
ated by the motion of the hull or
floats through the water. When the
seaplane is at rest on the surface, there
is no hydrodynamic lift, but as the
seaplane moves faster, hydrodynamic
lift begins to support more and more
of the seaplane’s weight.
IDLING POSITION
—The atti-
tude of the seaplane when its entire
weight is supported by the
buoyancy of the floats, as it is
when at rest or during a slow
taxi. Also called the displacement
position.
KEEL
—A strong longitudinal
member at the bottom of a float or
hull that helps guide the seaplane
through the water, and, in the case
of floats, supports the weight of the
seaplane on land.
RAMPING —Using a ramp that
extends under the water surface as
a means of getting the seaplane out
of the water and onto the shore. The
seaplane is typically driven under
power onto the ramp, and slides
partway up the ramp due to inertia
and engine thrust.
SAILING
—Using the wind as the
main motive force while on the
water.
SEA
—Waves generated by the
existing winds in the area. These
wind waves are typically a chaotic
mix of heights, periods, and wave-
lengths. Sometimes the term refers
to the condition of the surface
resulting from both wind waves
and swells.
SEA STATE CONDITION
NUMBER
—A standard scale
ranging from 0-9 that indicates the
height of waves.
SEAPLANE
— An airplane
designed to operate from water.
Seaplanes are further divided into
flying boats and floatplanes.
SEAPLANE LANDING
AREA
—Any water area designated
for the landing of seaplanes.
SEA W ARD
—The direction away
from shore.
SECONDARY SWELLS
—Those
swell systems of less height than
the primary swell.
SISTER KEELSONS
—Structural
members in the front portion of
floats lying parallel to the keel and
midway between the keel and
chines, adding structural rigidity
and adding to directional stability
when on the water.
SKEG
—A robust extension of the
keel behind the step which helps
prevent the seaplane from tipping
back onto the rear portion of the
float.
LEEW ARD —Downwind, or the
downwind side of an object.
MOOR
—To secure or tie the
seaplane to a dock, buoy, or
other stationary object on the
surface.
NUN BUOYS
—Conical buoys
marking the left side of a channel
for an inbound vessel. They often
have even numbers that increase as
the vessel progresses from seaward.
PLAIN SKI
—A type of aircraft ski
that can only be used on snow or ice,
as compared to combination skis,
which also allow the use of the
skiplane’s wheels for landing on
runways.
PLANING POSITION
—The atti-
tude of the seaplane when the entire
weight of the aircraft is supported
by hydrodynamic and aerodynamic
lift, as it is during high-speed taxi or
just prior to takeoff. This position
produces the least amount of water
drag. Also called the step position,
or “on the step.”
PLOWING POSITION
—A nose
high, powered taxi characterized by
high water drag and an aftward shift
of the center of buoyancy. The
weight of the seaplane is supported
primarily by buoyancy, and partially
by hydrodynamic lift.
POP-OUT FLOATS
—Helicopter
floats that are stored deflated on the
skids or in compartments along the
lower portion of the helicopter, and
deployed in the event of an emer-
gency landing on water.
Compressed nitrogen or helium
inflates the floats very quickly.
PORPOISING
—A rhythmic pitch-
ing motion caused by an incorrect
planing attitude during takeoff.
PORT
—The left side or the
direction to the left of a vessel.
PRIMARY SWELL
—The swell
system having the greatest height
from trough to crest.
Glossary.qxd 8/25/04 11:35 AM Page G-2
SKIDS-ON-FLOATS —A type of
helicopter float design where the
rigid portion of the landing gear
rests on the floats. The floats sup-
port the whole weight of the heli-
copter in water or on hard surfaces.
SKIPPING
— Successive sharp
bounces along the water surface
caused by excessive speed or an
improper planing attitude when the
seaplane is on the step.
SPONSONS
—Short, winglike pro-
jections from the sides of the hull
near the waterline of a flying boat.
Their purpose is to stabilize the hull
from rolling motion when the flying
boat is on the water, and they may
also provide some aerodynamic
lift in flight. Tip floats also are
sometimes known as sponsons.
SPRAY RAILS
—Metal flanges
attached to the inboard forward por-
tions of the chines to reduce the
amount of water spray thrown into
the propeller.
STARBOARD
—The right side or
the direction to the right of a vessel.
STEP
—An abrupt break in the
longitudinal lines of the float or
hull, which reduces water drag and
allows the pilot to vary the pitch
attitude when running along the
water’s surface.
STEP POSITION
—The attitude of
the seaplane when the entire weight
of the aircraft is supported by
hydrodynamic and aerodynamic
lift, as it is during high-speed taxi or
just prior to takeoff. This position
produces the least amount of water
drag. Also called the planing posi-
tion.
SWELL
—Waves that continue
after the generating wind has ceased
or changed direction. Swells also
are generated by ships and boats in
the form of wakes, and sometimes
by underwater disturbances such as
volcanoes or earthquakes. The
waves have a uniform and orderly
appearance characterized by
smooth, rounded, regularly spaced
wave crests.
SWELL DIRECTION
— The
direction from which a swell is
moving. Once set in motion, swells
tend to maintain their original direc-
tion for as long as they continue in
deep water, regardless of wind
direction. Swells may be moving
into or across the local wind.
SWELL FACE
—The side of the
swell toward the observer. The back
is the side away from the observer.
These terms apply regardless of the
direction of swell movement.
SWELL LENGTH
—The horizon-
tal distance between successive
crests.
SWELL PERIOD
— The time
interval between the passage of two
successive crests at the same spot in
the water, measured in seconds.
SWELL VELOCITY
— The
velocity with which the swell
advances with relation to a fixed
reference point, measured in knots.
There is little movement of water
in the horizontal direction. Each
water particle transmits energy to
its neighbor, resulting primarily in
a vertical motion, similar to the
motion observed when shaking out
a carpet.
TIDES
—The alternate rising and
falling of the surface of the ocean
and other bodies of water connected
with the ocean. They are caused by
the gravitational attraction of the
sun and moon occurring unequally
on different parts of the earth. Tides
typically rise and fall twice a day.
TIP FLOATS —Small floats near
the wingtips of flying boats or
floatplanes with a single main float.
The tip floats help stabilize the air-
plane on the water and prevent the
wingtips from contacting the water.
TRANSOM
—As it applies to
seaplanes, the rear bulkhead of a
float.
TROUGH
—The low area between
two wave crests.
UPSWELL
—Motion opposite the
direction the swell is moving. If the
swell is moving from north to
south, a seaplane going from south
to north is moving upswell.
VESSEL
—Anything capable of
being used for transportation on
water, including seaplanes.
WATER RUDDERS
—
Retractable control surfaces on the
back of each float that can be
extended downward into the water
to provide more directional control
when taxiing on the surface. They
are attached by cables and springs
to the air rudder and operated by
the rudder pedals in the cockpit.
WEATHERV ANING
—The ten-
dency of an aircraft to turn until it
points into the wind.
WINDW ARD
—Upwind, or the
upwind side of an object.
WING FLOATS
—Stabilizer floats
found near the wingtips of flying
boats and single main float float-
planes to prevent the wingtips from
contacting the water. Also called tip
floats.
Glossary.qxd 8/25/04 11:35 AM Page G-3
Glossary.qxd 8/25/04 11:35 AM Page G-4
Aids for marine navigation 1-2
Altimeter setting 6-7
Amphibians 2-1, 6-2
Anchoring 6-9
Autorotation 9-2, 9-6, 9-8
Auxiliary fin 2-4, 5-2
Beaching 6-8, 6-10
Bilge pump 4-2
Bilge pump openings 2-2, 4-2
Bulkheads, float 2-2
Buoyancy 2-2, 4-3
Buoys 1-2, 1-3, 1-4
Center of buoyancy 4-4, 4-6,
Center of gravity 4-1, 5-1, 5-2, 5-3, 7-7
Centrifugal force (in turns) 4-6, 4-7, 4-14
Certificate, limitations 1-1
Chine 2-2
Clamp-on ski 7-1
Coast Guard rules 1-2
Combination ski 7-1, 7-2
Confined area operations 4-16, 6-7
Corrosion 4-1, 4-3
Crosswind 4-12, 4-13, 6-3, 7-5
Current 3-2, 4-8, 4-9, 6-5
Daybeacons and daymarks 1-2, 1-3, 1-4
Deck 2-2
Density altitude 4-11, 4-12, 5-1, 6-8, 9-5
Displacement 2-2, 4-3
Displacement position 4-3
Displacement
of float 2-2
position or attitude 4-3, 4-10
taxi 4-3
Docking 6-8, 6-10
Downwind takeoff 4-14
Escaping a submerged seaplane 8-8
Fetch 3-2, 8-1
Float construction 2-2, 2-3, 9-1
Float, weight-bearing capability 2-2, 9-1
Floatplane defined 2-1
Flying boat
definition 2-1
handling 4-9, 5-3
Glaciers 7-6
Glassy water 3-3, 4-15, 6-5, 9-4
Go-around 6-2, 6-8
Hovering 9-3, 9-7
Hull 2-1, 5-3
Hump (water drag) 4-9, 4-10, 4-11
Hydrodynamic lift 2-2, 4-4, 4-10
Ice (in floats) 4-3
Ice types 7-2
Idling 4-3, 4-8
Inland waters 1-2
International waters 1-2
Index.qxd 8/25/04 11:36 AM Page I-1
Keel 2-2
Landings
confined area 6-7
crosswind 6-3
downwind 6-5, 8-4
emergency 6-8, 7-8
frozen lakes and rivers 7-6
glaciers 7-6
glassy water 6-5
helicopter 9-4, 9-8
night landing 6-8, 7-8, 8-5, 8-6
normal 6-3
open sea 8-1
rough water 6-7, 8-1, 9-5
skiplane 7-6, 7-7
tundra 7-6
Launching 4-3
Lighting conditions 7-6
Limitations of sea rating 1-1
Marine aids for navigation 1-2
Mooring 6-8, 6-9, 9-6
Night operations 6-8, 8-5, 8-6
Noise 3-4, 4-12, 6-2
Normal takeoff 4-12
On the step 4-4, 6-2
Parking 7-7
Passenger briefing 4-3
Penetration ski 7-2
Plain ski 7-1
Planing position 4-4
Plow turn 4-6, 4-7
Plowing position 4-4
Pop-out floats 9-1
Porpoising 4-9, 5-3
Preflight inspection
seaplane 4-1
skiplane 7-3
float equipped helicopter 9-3
ski equipped helicopter 9-7
Privileges and Limitations 1-1
Ramping 6-8, 6-10
Regulations 1-1
Retractable ski 7-1
Right-of-way rules 1-2
Roll-on ski 7-1
Rough water 4-16, 6-7, 8-1, 9-5
Rules of the Sea 1-2
Runup 4-12
Runup (skiplane) 7-4
Sailing 4-8, 4-9
Seaplane defined 2-1
Seaplane landing areas
beacons 1-2
chart symbols 1-2
reconnaissance 6-1
restrictions 3-4
unplanned 5-2
Sister keelsons 2-2
Skeg 2-2, 2-4
Ski types 7-1
Skids-on-floats 9-1, 9-6
Skipping 4-10
Snow types 7-2
Sponson 2-1
Spray damage 4-1
Spray rail 2-2, 4-2
Starting
seaplane 4-3
skiplane 7-4
helicopter 9-3, 9-7
Step 2-3, 4-4
Step position 4-4
Step taxi 4-5, 6-3
Step turns 4-7
Survival equipment 7-3, 7-4, 7-8
Swell 3-2, 4-9, 6-2, 6-7, 8-1, 8-2, 8-3, 8-4, 8-5
Index.qxd 8/25/04 11:36 AM Page I-2
Takeoffs
normal 4-12
crosswind 4-12
downwind 4-14
helicopter 9-4, 9-7
glassy water 4-15
rough water 4-16, 8-1
confined area 4-16
skiplane 7-5
Taxiing
seaplane 4-3
skiplane 7-5
float equipped helicopter 9-3
ski equipped helicopter 9-7
Tides 3-3
Tip floats 2-1
Transom 4-2
Turns 4-5, 4-6, 4-7
Types of ice 7-2
Types of snow 7-2
Warmup (skiplane) 7-4
Water current 3-2, 4-8, 4-9, 6-5
Water rudders 2-4, 4-2, 4-5, 4-12, 4-14,
Water, characteristics 3-1, 8-1
Watertight compartments 2-3, 4-2
Waves 3-1, 6-3,
Weathervaning 3-4, 4-5, 4-6, 4-13, 6-3
Weight and balance 4-1, 5-1
Wheel replacement ski 7-1
Wing floats 2-1
Yaw instability 2-4, 4-6, 5-2, 9-2