River Diving: Technique
by
Larry "Harris" Taylor, Ph.D.
This
is an electronic reprint and expansion of a portion of a three part series on river diving
that appeared in SOURCES (May/June
1990, p. 33-34). This
article is made available as a service to the diving community by the author.
This article may be distributed for any non-commercial or Not-For-Profit use.
All
rights reserved.
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River
diving can place exceptional physical demands on the diver. Thus, river divers
should be in good, if not superb, physical
Divers
should have a separated-diver plan. This is not a major problem while drift
diving with both divers on a line connected to a float. However, in some intense
current situations, towing a float is both unsafe and impractical. Where we most
often play, there is an erosion barrier break-wall along the entire length of
the river; the current is 2-10 knots and boat and fishing traffic is heavy; a
direct ascent to the surface is not a desirable option. Also, in that current, a
diver above the river bottom, especially on the surface, will rapidly increase
the separation distance between buddies. Under those circumstances we have
adopted the following plan: Before the dive, one diver is named the
"designated mover," the other diver is the "designated
non-mover." When separated,
both divers look around and then move to the wall along shore. Upon reaching the
wall, the "non-mover" remains stationary for three minutes and then
surfaces along the break-wall.. On
the surface, the "non-mover" holds position along the wall by placing
the river stick into the corrugated steel structure and notes the location.
The "mover" (usually the most experienced river diver) goes to
the wall and moves upstream for two minutes and then downstream for one minute
and then surfaces. Once surfacing, the divers wait 10 minutes and then, if no
contact is established, call for rescue assistance. Since the divers have
surfaced along the wall, the last known point can be reasonably established, if
a search is necessary. Note that the above plan is not universal. It is used by
experienced river divers diving near shore in intense current with a restrictive barrier
along the shore. Under these
circumstances such a plan has been useful.
Mover/Non-Mover Strategy Needs Fixed Barrier to be Effective
"Stick and Glide"
The
essence of all diving is to move in harmony with the environment. In all
confrontations between Mother Nature and humans, the human will lose. Thus, the secret to
successful river diving is to "go with the flow" and to do so with
control. The cardinal rule of river diving is "keep your fins lower than
your ass." When moving in
intense current near the bottom of the river, move with legs spread (like a
"spider") and drag your fins along the bottom. (Remember fins
should NOT have large openings, as these holes are potential places for
objects on the river bottom to impale the diver's fins. This has resulted in the
loss of diver's fins and has the potential worst-case scenario of pinning the
diver on the bottom.) If your fins get higher
than your buttocks, then you are more likely to lose control and tumble. If you
find you legs rising, kick hard and drive downward at a slight angle.
Once velocity is established raise the head and allow the legs to get
below your buttocks. The preferred orientation is moving headfirst or sideways
down the river. By moving sideways, the silt from your dragging fins will not
cloud your visibility. Moving sideways allows two divers to stay together by moving down
stream facing each other. In some areas, particularly in a clay bottom, the visibility
can deteriorate
The
real key to control in the river, however, is the use of the "river
stick." This device is used to help pull the diver upstream, to
"Stick & Glide" - Stick holds orientation and controls downstream speed
Freehand stabilizes position and moves ahead of diver
The "stick" also allows a diver, with physical exertion, to move upstream. This is done by extending the "stick" ahead of the diver to either hook an object, (large rock, tree branch, or debris), on the bottom or, if the bottom allows, drive the stick into the bottom. This "reach-and-pull" can also be used with a technique we call the "inchworm." This involves anchoring the "river stick" and then lifting the back into an arched position. The current moving over the arched back assists in holding the diver on the river bottom. Once an arched position is achieved, then the arm holding the "stick" is extended and the cycle is repeated. This successive reach and collapse (like the movement of an inchworm) is physically demanding and used primarily only for short excursions in moderate current. In some cases, it is possible to use this technique without a "stick."
The "inchworm" technique
The
"Creeper"
A device known as the "creeper" facilitates moving upstream. The "creeper" is typically home made from one-half inch steel bar stock (See river diving equipment for specifications ). Basically, the creeper is a three-legged device; with the back leg a central anchor point. The diver alternatively pivots on each of the forward legs and moves it forward to a new anchor point. The diver thus "zigzags" a course upstream. Using a "creeper" can be strenuous, especially when significant distances must be covered. To assist the diver, we have done the following: a large ( 3 inch) snap shackle on a short (18 inch) line is attached to the chest harness of the diver. The other end of this short line has an eye-splice loop. A non-locking carabineer connects the short line to a 4" steel ring that is attached to the "creeper" (see photo of the creeper in river diving equipment). When the diver is tired, the diver can release the hand grip and allow the line between harness and creeper to hold position without physical exertion. Once rested, the diver can once again grab the creeper and move forward. The large snap shackle allows the diver easy access to the connection should the diver need to release from the "creeper." The large ring also serves as an anchor point for a dive flag (so surface support can monitor progress/position), a "y-yoke" for two divers using the "creeper" in search mode, and as a place to secure a line for raising and lowering the "creeper" between the water and the surface support platform.
The "creeper" can be a convenient anchor point/search platform for probing or excavating the bottom of swift water areas. For this application, the "creeper" is secured to the bottom and one or two divers work behind the creeper. The diving flag is secured to a large steel ring on the "creeper" using a non-locking carabineer. This allows the creeper, rather than the divers, to bear the burden of holding the flag in place against a strong current. In addition, the flag gives surface support staff a method of documenting position searched by the divers. The divers can use the same "y" yoke used in drift diving (See river diving equipment for specifications). In this case, the "Y" yoke (see below) is hooked to the ring on the "creeper." This allows divers to stay together and communicate (via rope tugs), even in extremely low visibility. One advantage to working in current is the rapidly moving water clears the area of debris as it is lifted out of the hole being dug
We have used the "creeper" in either single or 2-diver per device mode. In a single diver mode, during excavations, the diver works in the immediate vicinity of the creeper. In a search mode (see below), the diver, using the "creeper" as an anchor, can run repetitive, increasing distance pendulum arcs away from the creeper
With two divers per "creeper", both divers, each on a different side of the stationary "creeper" can work on excavation. In search mode. a line can be deployed directly behind the creeper. Our double buddy line ("Y-yoke," see Equipment ) is secured to the search line and then both divers can run a search pattern parallel to the baseline.
"Flying"
One special thrill of intense (> 4 knot) current diving is to "fly" 6-10 feet off the bottom and let the current hurl you downstream. As long as visibility gives the diver enough time to avoid objects, this can be an exceptionally challenging and invigorating activity. This activity is only for divers with sufficient swift water experience to be comfortable in such intense current.
Conclusion
River diving, like all specialty environments, has its own set of requirements with respect to diving equipment and techniques. The unforgiving nature of extreme current flow has cost many divers their lives. This is one specialty area that most definitely requires techniques and equipment different from typical open water recreational training.
This is one portion of series of articles on river diving. Others are
Reading Rivers River Diving: Navigating In Currents River Diving: Equipment
Lecture Slides for the river diving course at River
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Photo Credits:
Surface Photography: Larry "Harris" Taylor
Diver Underwater: Mike Spears
Sketch Artwork by Maureen Reilly
Larry
"Harris" Taylor, Ph.D. is a biochemist and Diving Safety Coordinator
at the University of Michigan. He has authored more than 200 scuba related
articles. His personal dive library (See Alert Diver, Mar/Apr, 1997, p. 54) is
considered one of the best recreational sources of in North America.
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Use of these articles for personal or organizational profit is specifically denied.
These articles may be used for not-for-profit diving education.