Atlantic Intracoastal Waterway (AIWW) is a the toll-free
“canal” which affords continuous protected passage behind the Atlantic
Coast and the Florida Keys for more than 1,243 statute miles between
Norfolk, VA, and Key West, FL. Shortly after Norfolk, the waterway bifurcates
and offers 2 alternative routes: Route 1, the basic route, follows Albemarle
and Chesapeake Canal to Albemarle Sound; Route 2, the alternate route,
is through Great Dismal Swamp Canal to the sound.
The Intracoastal Waterway is used by commercial light-draft vessels
and tows unable to navigate long stretches in the open ocean, and by
pleasure craft. Small-boat and recreation facilities are found along
the waterway. Supervision of the waterway ’s construction, maintenance,
and operation is divided among five U.S.Army Engineer Districts (Norfolk,Wilmington,Charleston,Savannah,and
The Intracoastal Waterway mileage is zeroed in 36 °50.9'N., 76 °17.9'W.,
off the foot of West Main Street, Norfolk, VA, and progresses southward
to I.W. Mile 1243.8 at Key West, FL, in 24 °33.7'N.,81 °48.5'W. Distances
along the Intracoastal Waterway are in statute miles to facilitate reference
to the small-craft charts; all other distances are nautical miles.
The Federal project for the Intracoastal Waterway via Albemarle and
Chesapeake Canal provides for a least depth of 12 feet from Norfolk,
VA, (I.W.Mile 0.0) to Fort Pierce, FL, (I.W.Mile 965.6), thence 10 feet
to Miami, FL, (I.W.Mile 1089.0), and thence 7 feet to Key
West, FL, (I.W.Mile 1243.8). The Miami to Key West section of the waterway
has been completed only as far as Cross Bank (I.W.Mile 1152.5); the
remainder has been deferred for restudy. Although no work has been performed
on this section of the waterway, a channel, marked in accordance with
I.W. markings, leads from Cross Bank to Big Pine Key along the northwesterly
side of the Florida Keys. At Big Pine Key, the waterway bifurcates going
north through Florida Bay or souththrough Hawk Channel to Key West.
The channel has a controlling depth of about 5 feet and is exposed to
winds from the northwest.(See Local Notice to Mariners and latest editions
of charts for controlling depths of the Intracoastal Waterway.)
The minimum overhead clearance of fixed bridges over the Intracoastal
Waterway is 56 feet at the Julia Tuttle Causeway at Miami, Mile 1087.1,
but most fixed bridges have a clearance of 65 feet.
The minimum clearance of overhead cables crossing the Intracoastal Waterway
is 68 feet in Snows Cut, Mile 295.8 . An overhead cable car at Mile
356.4 has a least clearance of 67 feet under the low point of travel
of the cabin.
Caution: When running with a fair tide or in windy weather, exercise
caution when approaching and passing bridges and sharp turns.
No vessel owner or operator shall signal a drawbridge to open if the
vertical clearance is sufficient to allow the vessel, after all lowerable
nonstructural vessel appurtenances that are not essential to navigation
have been lowered, to safely pass under the drawbridge in the closed
position; or signal a drawbridge to open for any purpose other than
to pass through the drawbridge opening.
The operator of each vessel requesting a drawbridge to open shall signal
the drawtender and the drawtender shall acknowledge that signal. The
signal shall be repeated until acknowledged in some manner by the drawtender
The signals used to request the opening of the draw and to acknowledge
that request shall be sound signals, visual signals, or radiotelephone
Great Bridge Lock (mile 11.5)is the only lock on the Intracoastal Waterway
between Norfolk and Key West via Albemarle and Chesapeake Canal. It
is 600 feet long (530 usable),75 feet wide (72 feet usable),16 feet
over the sills,and has a lift of 2.7 feet.
Aids to navigation
Intracoastal Waterway aids have characteristic yellow markings which
distinguish them from aids to navigation marking other waters.
Lights and daybeacons should not be passed close aboard because those
marking dredged channels are usually placed back from the bottom edge
of the channel and others may have rip-rap mounds around them to protect
Navigation of the Intracoastal Waterway can be made easier by use of
the special small-craft series which the National Ocean Service publishes.
Charts #: From North to South, 12206, 11553, 11541, 11534, 11518, 11507,
11489, 11485, 11472, 11467, 11451, 11445, 11446, 11448.
Under ordinary conditions the mean range of tide in the waterway is
from nontidal to about 7 feet. In many sections, the tide depends on
the force and direction of the wind.
The Intracoastal Waterway affords protection from the winds and waves
of the offshore Atlantic. Land creates friction that reduces windspeeds
by as much as 30 percent of those over the open sea. Wave heights are
reduced by shallow depths and limited fetch. When severeweather does
strike,shelter is usually close by,either up a protected river or at
a nearby port. However,navi gation becomes more critical in many restricted
reaches along this route, so that weather, as well as tides and currents,
is important. The waterway is covered by a network of National Weather
Service VHF-FM radio stations that provide continuously updated forecasts
There are many small-craft facilities along the Intracoastal Waterway.
Navigation on the waterways requires a knowledge of the channel
conditions and other factors restricting navigation.
Where two streams cross,the current will have a greater velocity in
the deeper channel. This is noticeable along the Intracoastal Waterway
where it follows a dredged canal cutting across a winding stream. Cross
currents will also be noticed where either an inlet from the ocean or
a drainage canal enters the waterway. Cross currents are especially
strong at New River Inlet and Bogue Inlet, N.C. Failure to allow for
cross currents when passing these and other inlets is the cause of many
rescue calls to the Coast Guard.
Bends or Curves
In the Intracoastal and adjoining waterways there are many sharp bends
which are dangerous to vessels meeting or passing. On approaching a
bend, a vessel should reduce speed sufficiently to be able to stop within
half the distance to a ship coming from the opposite direction. Under
no circumstances should a vessel attempt to overtake and pass another
at a bend.
Stumps and sunken logs
Reports are frequently made that vessels have struck shoals or rocks
in rivers which have later proved to be stumps or sunken logs.Mariners
are warned against navigating too close to the banks of streams where
submerged stumps are known or may be expected to exist.
On receiving advisory notice of a tropical disturbance small boats should
seek shelter in a small winding stream whose banks are lined with trees,preferably
cedar or mangrove. Moor with bow and stern lines fastened to the lower
branches;if possible snug up with good chafing gear.The knees of the
trees will act as fenders and the branches,having more give than the
trunks,will ease the shocks of the heavy gusts.If the banks are lined
only with small trees or large shrubs, use clumps of them within each
hawser loop. Keep clear of any tall pines as they generally have shallow
roots and are more apt to be blown down.
A clear channel shall at all times be left open to permit free and unobstructed
navigation by all types of vessels and rafts that normally use the various
waterways or sections thereof.
Stoppage in waterway, anchorage or mooring.
No vessels or rafts shall anchor or moor in any of the land cuts or
other narrow parts of the waterway, except in case of an emergency.
Whenever it becomes necessary for a vessel or raft to stop in any such
portions of the waterway it shall be securely fastened to one bank and
as close to the bank as possible. This shall be done only at such a
place and under such conditions as will not obstruct or prevent the
passage of other vessels or craft. Stoppages shall be only for such
periods as may be necessary.
When tied up, all vessels must be moored by bow and stern lines, to
insure their not being drawn away from the bank by winds,currents or
the suction of passing vessels.In narrow sections,no vessel or raft
shall be tied abreast of another.
No vessel, regardless of size, shall anchor in a dredged channel or
narrow portion of a waterway for the purpose of fishing, if navigation
is obstructed, thereby.
Vessels shall proceed at a speed which will not endanger other vessels
or structures and will not interfere with any work in progress incident
to maintaining, improving, surveying or marking the channel.
Official signs indicating limited speeds through critical portions of
the waterways shall be strictly obeyed. Vessels approaching and passing
through a bridge shall so govern their speed as to insure passage through
the bridge without damage to the bridge or its fenders.
No vessel or tow shall navigate through a drawbridge until the movable
span is fully opened.
Meeting and passing
Vessels, on meeting or overtaking, shall give the proper signals and
pass in accordance with the Navigation Rules. All vessels approaching
dredges, or other plant engaged on improvements to a waterway, shall
give the signal for passing and slow down sufficiently to stop if so
ordered or if no answering signal is received.
On receiving the answering signal, they shall then proceed to a pass
at a speed sufficiently slow to insure safe navigation.