Chapter 8- Wreck Diving
Wreck Diving
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PROCEDURES
Your first task is to locate a wreck. For this course,
that is the responsibility of your instructor. Other sources
include commercial dive boats, commercial fishermen,
charts, record searching, and other divers. Finding a
wreck can often be as challenging and rewarding as diving
on it. Always be sure the wreck you seek will be within
your limits of ability.
When you find a wreck and enjoy diving on it, you will
need to carefully mark your location so you can relocate
the wreck for future dives. This can be done by taking a
“fix” as described elsewhere, taking bearings carefully, and/
or using a GPS or other electronic navigation equipment.
If you only have a general position, when you arrive in the
vicinity you will want to pinpoint the wreck as closely as
possible. This may be done with the aid of a depth sounder/
finder, a magnetometer (metal detector), or by dragging a
weighted line or grapple in an attempt to snag the wreck.
When your instructor or the boat captain locates a wreck
for your dive, pay attention to the techniques used so you
can better understand them.
Your planning for the dive needs to be more involved
than usual. You should obtain drawings, diagrams, or
pictures of the wreck so you can familiarize yourself
with it. Note the dimensions, the shallowest and deepest
depths, and the orientation of the wreck with respect
to the bottom and to compass direction for purposes
of navigation. Does the wreck parallel the shoreline or
run perpendicular to it? Information such as this can
help you locate a wreck and navigate better while you
are diving on it. Find out if the wreck is intact. Consult
the tide tables to determine slack water time. Find out
about potential hazards and prepare yourself to be able to
identify them and cope with them. All of these steps are
necessary in addition to all of the regular ones of your
dive plan.
As mentioned, wreck diving is often done from a
boat. Upon arrival at the vicinity of the wreck, use the
time spent pinpointing its location to evaluate conditions.
Estimate depth, current(s), visibility and the stability of
the current weather pattern to decide whether or not it
is appropriate to dive. Conditions can be further checked
as the boat is being anchored and you set up for the dive.
Watch the anchor as it is lowered to check the visibility,
and watch the trail line float, as it pays to check out the
strength of the current.
Be aware that an anchor line can be chafed or cut
by a wreck if you anchor on one, but this is a common
and reliable way to position a vessel for wreck diving.
However, if you can get on the wreck without anchoring
in it, this is preferred, since anchors can severely damage
wrecks, spoiling them for future dives.
If diving from a private vessel, it is a good idea to
check the anchor and make sure it is secure. The next
step is very important – orienting yourself to the anchor
line and to the wreck itself. Which way is the wreck
positioned in relation to the line? What distinguishing
features of the wreck can be used to help you recognize
the area where the anchor line is located? Use the techniques
to which you were introduced on your navigation
dive. Get a compass bearing so you will be able to return
to the anchor line for your ascent. Pick out a landmark
at the far limit of the visibility and work your way to it.
Upon reaching the landmark, look back to view what
you have traversed from the opposite direction, then look
ahead to the next landmark or feature, work your way to
it and so forth. To return, just proceed from landmark to
landmark in the reverse order. It is common for wrecks
to have a pattern to them. If you can quickly identify this
pattern, it will help quite a bit with your orientation. You
can also see why studying illustrations of the wreck in
advance can be very helpful.
Before beginning your tour of a wreck, check again
for current(s). Remember currents can change in intensity
and/or direction during your dive. If the direction of
the current is not in line with the ship’s hull and you can
dive along the lee (sheltered) side, explore the sheltered
portion of the wreck first.
As you proceed along the wreck, move carefully so
little or no silt will be raised. Pull yourself along with
your hands as much as possible. Swim with your fins at a
slight upward angle so their thrust will not stir up clouds
of sediment. Try using a frog or a scissor kick that moves
water from side to side, rather than the usual flutter kick,
which moves water up and down and can stir things up.
Kicking up silt can ruin the visibility for you and for other