S
cuba divers often find themselves sharing the
water with boats, as divers use boats to travel
to dive sites and sometimes dive in areas with
heavy boat traffic. Collision injuries from
vessels and propeller strikes are hazardous for divers
in such areas.
The U.S. Coast Guard Boating Safety Resource Center
reports that from 2005 to 2013 boat-propeller strikes
caused 636 injuries and 38 deaths of people engaged
in water activities (boating, water skiing, swimming,
snorkeling, diving, tubing, etc.); 442 of these injuries and
29 of these deaths were caused by a person being struck
by a vessel. Preventing accidents while diving in areas
with boat traffic requires that divers be aware of vessels at
all times both below the surface and topside.
Depending on the location and vessel type, licensure
or certification through boat-safety education courses
may be required. Boating laws vary internationally
and by state in the U.S.; therefore, it is important that
both boat operators and divers remain aware of the
regulations in effect for a specific location.
SIGNALING TOOLS
Dive flags. Flying a dive flag is an effective and in some
places required means of alerting boats that divers are
in the water. Similar to boat-operation laws, dive-flag
regulations vary by location and vessel type in the
U.S. and internationally. The two types of flags most
commonly recognized in relation to diving are the
alpha flag and the diver-down flag.
The internationally recognized alpha flag is flown
when the mobility of any vessel is restricted, indicating
that other vessels should yield the right of way. This
flag is often flown along with the diver-down flag
when divers are in the water, because dive boats must
maintain a close vicinity to the divers and cannot
quickly move. The diver-down flag explicitly signals that
a diver is in the water, and it should always be flown
from a vessel that has divers in the water. The alpha flag
indicates that divers are in the area; however, it also has
other uses. It is best practice to fly the diver-down flag
along with the alpha flag to avoid miscommunication.
A diver-down flag is recommended to alert vessels
during shore diving. The distance divers are required
to stay within the dive flag depends on the dive
location. A floating buoy tethered to a dive reel can be
used to signal where divers are located in the water.
A reel towing a floating dive flag should never be
attached directly to the diver. Carrying the reel helps
prevent the diver from being dragged in case the flag is
caught by a passing boat.
Whether the dive flag is flown on a boat or a buoy
marker, the flag should be in good condition to ensure
visibility. Replace the flag when the safety integrity is
compromised by faded color or rips. The size of the
required dive flag may also vary by location. Always
make sure the flag is visible from all directions.
Surface markers. Safety tools such as surface marker
buoy (SMBs), whistles and other audible signals,
dive lights and signaling mirrors can be used to
communicate your location to boaters after you ascend
from a dive. An SMB may be used in addition to a dive
flag for alerting boaters that divers are in the water.
Before the dive, review how to deploy the SMB to be
prepared for using it on ascent.
When using signaling devices at the surface, divers
should never assume they are visible to boat operators.
52
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FALL 2014
B Y B R I T T A N Y T R O U T
Boat Collision
and Propeller
Safety
RESEARCH, EDUCATION & MEDICINE
//
S A F E T Y 1 0 1
STEPHEN FRINK
