112
|
SPRING 2014
GEAR
S
urface marker buoys (SMBs) are
designed to be inflated at depth and
sent to the surface at the end of a
line. By inflating an SMB at depth a
dive team marks their position at the
beginning of their ascent, allowing them
to perform a safety stop or required
decompression while the boat maneuvers into position.
In theory, this minimizes the amount time divers must
spend on the surface waiting to be picked up and
maximizes their visibility — and thus, safety.
Divers generally deploy SMBs while neutrally
buoyant in the water column, so they must take care
not to drop the reel or finger spool, which may be
negatively buoyant. There should be at least 50 percent
more line on the reel than the depth from which the
SMB is being deployed. Before deploying an SMB,
look up to make sure the boat hasn’t already found
you or that a group of divers isn’t directly overhead. A
tiny puff of gas is generally sufficient to keep an SMB
upright and makes it easier to manage by preventing it
from ascending too quickly.
Some SMBs have overpressure valves (OPVs), which
relieve pressure as the buoy ascends and the gas inside
it expands. OPVs are generally one-way valves that
won’t dump gas once the SMB is on the surface. SMBs
with open bottoms do not require OPVs; however,
these will dump air if they fall over.
Some divers use a dedicated low-pressure hose with
an air tool attachment, but this equipment is probably
unnecessary unless you plan to inflate an SMB or a lift
bag on every dive. Aside from this dedicated piece of
gear there are three basic methods for inflating SMBs,
and each has its pros and cons. Whichever technique
you choose will require training and practice. Be
neutrally buoyant and well trimmed before you begin.
We’re Over Here!
Using surface marker buoys safely and effectively
B y P e t e N a w r o c k y
This article is designed to offer tips for better deployment of surface marker buoys from depth.
This is a skill that should be practiced under the guidance of a qualified instructor.
STEPHEN FRINK
