10 Tips for Diving In Surge
When the waves are rocking, don't come knocking. Follow these tips for diving safely in
surging water.
Surge is the forward-and-back movement of water caused by wave action. It can be a
problem near rocks and shallow wrecks, and when approaching an anchored dive boat.
Here's what to do:
Step 1: Back Off
Surge, like the waves that cause it,
comes in sets of stronger flows, and
lulls of weaker ones. If your problem
is to approach the boat ladder, back
off a few yards and watch the situation
until you can read the rhythm of sets and lulls.
Step 2: Don't Fight It
Even moderate surge is stronger than
you are. Don't exhaust yourself trying to
move forward against it. Instead, hold
on to something (a current line, an
anchor line, a rock) when the surge tries
to carry you backward, and ride it when
it carries you forward. Nothing to hold
on to? Fin steadily forward just enough
to remain stationary. Backward and
forward flows are about the same and
will cancel out.
Step 3: Timing Is Everything
Wait for a lull (a period of weaker flows) to make your move. Exiting the water? If you time it
right, you can ride an inflow to the ladder or rock, hang on during the outflow, and climb out
during the slack water before the next inflow. Going through a wreck opening or
swim-through? Likewise, ride the inflow to the edge, hang on during the opposite force,
then use the lull and inflow to swim through and away from the opening where the surge is
strongest. Be cautious on your approach. It's better to fall short of the ladder or opening and
have to do it again than to be thrown against it.
When Surge Is Strongest
In shallow water. Usually you can avoid surge by going below 10 or 20 feet. (But it depends
on the size of the waves.)
When waves are big. Big surf means surge is not only stronger but reaches deeper.
At narrow openings. Remember the venturi effect? Surge accelerates in gaps between
rocks and through openings in wrecks.
Around stationary objects. When water has to make a detour around a rock outcrop or a
wreck, it goes faster.
Why Doesn't the Boat Move?
You and the dive boat are both floating. How come the surge moves you but not the boat?
Actually, the boat probably does move, especially if it's small. But the heavier it (or any
object) is, the more inertia it has to resist the surge. And it may be big enough to span
several waves at once--in which case inflows and outflows cancel each other and it's as
immobile as a rock. Plus, if the boat is at anchor, the anchor line restrains the boat's
movement.
When the waves are rocking, don't come knocking. Follow these tips for diving safely in
surging water.
Surge is the forward-and-back movement of water caused by wave action. It can be a
problem near rocks and shallow wrecks, and when approaching an anchored dive boat.
Here's what to do:
Step 1: Back Off
Surge, like the waves that cause it,
comes in sets of stronger flows, and
lulls of weaker ones. If your problem
is to approach the boat ladder, back
off a few yards and watch the situation
until you can read the rhythm of sets and lulls.
Step 2: Don't Fight It
Even moderate surge is stronger than
you are. Don't exhaust yourself trying to
move forward against it. Instead, hold
on to something (a current line, an
anchor line, a rock) when the surge tries
to carry you backward, and ride it when
it carries you forward. Nothing to hold
on to? Fin steadily forward just enough
to remain stationary. Backward and
forward flows are about the same and
will cancel out.
Step 3: Timing Is Everything
Wait for a lull (a period of weaker flows) to make your move. Exiting the water? If you time it
right, you can ride an inflow to the ladder or rock, hang on during the outflow, and climb out
during the slack water before the next inflow. Going through a wreck opening or
swim-through? Likewise, ride the inflow to the edge, hang on during the opposite force,
then use the lull and inflow to swim through and away from the opening where the surge is
strongest. Be cautious on your approach. It's better to fall short of the ladder or opening and
have to do it again than to be thrown against it.
When Surge Is Strongest
In shallow water. Usually you can avoid surge by going below 10 or 20 feet. (But it depends
on the size of the waves.)
When waves are big. Big surf means surge is not only stronger but reaches deeper.
At narrow openings. Remember the venturi effect? Surge accelerates in gaps between
rocks and through openings in wrecks.
Around stationary objects. When water has to make a detour around a rock outcrop or a
wreck, it goes faster.
Why Doesn't the Boat Move?
You and the dive boat are both floating. How come the surge moves you but not the boat?
Actually, the boat probably does move, especially if it's small. But the heavier it (or any
object) is, the more inertia it has to resist the surge. And it may be big enough to span
several waves at once--in which case inflows and outflows cancel each other and it's as
immobile as a rock. Plus, if the boat is at anchor, the anchor line restrains the boat's
movement.
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
All About Florida
Keys Scuba
Diving and
Florida Keys Dive
Trips
Keys Scuba
Diving and
Florida Keys Dive
Trips
Florida Keys Diving
________________________________________________________________________________________________________________________________