Drift Diving - How to slow down and stay with your buddy/group

[Scott 2000]

I was in Cozumel on a drift dive a few weeks ago in a strong current and found that I was moving much faster than everyone else in my diving group. At one point, I looked up and had lost complete sight of everyone that I had dropped down with.

Obviously, I like to stay close to my dive buddy, so I'd like to learn a better way of handling similar situations in the future.

A couple of specific questions I have:
1. Why do divers move at different speeds during a drift dive?
2. What's the best way to reduce speed in general?
3. Assuming it's not possible or difficult to reduce speed, what's the easiest way to stop to wait for divers that are moving slower? In this case, I found a sandy spot at one point and was able to dig in and hold on without impacting the coral. Any other ways (especially if there is no sand to be found)?

Thanks for the tips!

 

[Steelyeyes]

You can get down current of any structure above the bottom and be in a protected spot from the current. Just tuck into the eddy, no hanging on required. Watch how the fish do it.

 

[Angelo Farina]

Over a flat surface, the water speed is not constant, it gets a vertical gradient: slow speed close to the surface, increasing speed as you go up.
So staying very deep, close to the surface, slows you down, staying higher than your mates makes you running faster. That's basic flow dynamics...
Here the typical speed profile vs. depth on a 10-meters deep flat surface:

 

[D_Fresh]

A couple of specific questions I have:
1. Why do divers move at different speeds during a drift dive?
2. What's the best way to reduce speed in general?
3. Assuming it's not possible or difficult to reduce speed, what's the easiest way to stop to wait for divers that are moving slower? In this case, I found a sandy spot at one point and was able to dig in and hold on without impacting the coral. Any other ways (especially if there is no sand to be found)?

Thanks for the tips!

1. Simply put: Drag and Depth (depth as in height off of bottom). Depth for the reasons stated above. And Drag will play a huge part anywhere in the water column, same as it does with wind on the surface. A larger bodied diver would have more drag than a smaller bodied diver, as would a diver with lots of dangling floppy items vs a diver with a streamlined* kit, or a diver with spread limbs vs a diver tucked like a skier. (*Yes, I know, buzzword, but it actually applies here)

2. Reduce Drag, Stay closer to the bottom or reef, and if you need more "braking" turn into the current and swim against it*. *Important to know that most divers cannot make headway against a 1 to 2 knot current, so don't try to, but even gentle finning should help to slow your progress.

3. As mentioned above, the best option would be stay as close as possible to the bottom and/or just down current behind a large feature or reef wall. *(Down current as in down wind, not a down-current)* Otherwise, if acceptable at the site, holding or reef hook on bare rock or dead coral. And as absolute last resort, if maintaining position is a matter of absolute danger or life n death, Grab Something, Anything!

 

[rongoodman]

You can also reduce drag by presenting less body surface area to the current, i.e., get flat in the water.

 

[divad]

You could turn and face the group.... then later tell them how much you so enjoy the back-kick.

 

[Scared Silly]

Welcome to da board.

As said above, the three D's

1. Stay deep - the current is slower near the bottom
2. Reduce drag - making it easier to swim into the current
3. and duck behind stuff - not different than a wind break.

 

[johndiver999]

Attempting to reduce drag by changing orientation is going to be ineffective unless you are swimming against the current or holding onto something.

 

[Angelo Farina]

Drag reduction is a common misconception. If you are not moving relative to the water surrounding you, having large or small drag does not make any difference.
Instead drag becomes suddenly important whenever you start kicking for moving relative to water. For example, when you try swimming against current. But also when swimming along current.
When you move relative to water, minimizing drag (streamlined equipment, correct attitude) and maximizing thrust (long freediving fins of proper stiffness and proper kicking method) is the way to reach an higher relative speed while minimizing effort.
But if instead you leave to the current the job of propelling you (as it should be done in a drift dive), then drag is entirely irrelevant. You speed up when you are shallower and you slow down when you are deeper.

 

[scubadada]

Turn around and kick modestly into the current, the group will quickly catch up

My problem in SE Florida is on drifts where I always have the flag. I frequently move faster in brisk currents. I will occasionally hook into the reef to get the group back together