dumpsterDiver
Banned
- Messages
- 9,003
- Reaction score
- 4,652
- # of dives
- 2500 - 4999
Wow this is really surprising that so many people don't understand currents and the physics. There is no drag if the diver is passive and neutral and the flow is uniform. Shape or size or orientation does NOT matter under these assumptions. Do skinny people go faster when carried by a bus, train or airplane or when riding in a hot air balloon?
If you are getting separated from the group when drift diving, then you need to kick a little. If they are hugging the bottom the current is slower.
This is an important one... that inexperienced people don't understand and experienced divers do intuitively.... Be like a bird or a fish... Have you ever seen birds standing on the beach? They all face the same way? Why? because they keep their nose into the wind.. same for schooling fish, they tend to swim into the current. So when a diver stops and wants to hold stationary in a current, you often have to spin around..
For example, you are drifting north, you look ahead and see something you would like to stop and look at. If you just stop and tilt your head down and look and maybe grab a rock and dump a little air... You will have a problem. The current will grab your fins and try to flip you over. There will be a ton of drag and turbulence and the diver will be kicking and flailing around trying to hold position.
The experienced diver instictively knows that when he wants to stop and hold onto something, he needs to spin around as he stops and put his nose into the current. In fact, if you are just a slight bit heavy and you assume a head down position, and hold your body kinda straight, you will be like a wing pointing down and the current will push you down toward the bottom and help to hold you stationary. you want your head down.
Conversely, if you stop, spin around and face the current, but keep your head up and fins low.. what will happen?... the currrent will tend to get under your belly and you will be like a wing again, but this time it will be trying to lift you up and pull you away from the bottom. You will be "floating up", even though you dumped air and were neutral when you were drifting..
So it is simple, when you stop, face the current, be streamlined, not sideways, keep your head down and the closer you body is to the bottom, the lower the drag. The current will not slow down much 2 feet off a smooth bottom, but if you get your belly 6 inches from the bottom, the current will drop off a lot.
I was watching this video with my son the other day and I commented on the exact thing that I am talking about... In this video we are drifting with the current from the right toward the left. We are drifting and swimming with the current. When he shoots a fish at around 1:00 in the video, he just instictively spins around to face the current and remain stationary while he deals with the fish. I complimented him on it when watching the video and he just laughed and said "doesn't everybody do that"?... The answer of course is NO.
On this day the current was really pretty mild, but I thought it was a decent example of what i was talking about.
7 10 12 Ft Pierce scuba spearing - YouTube
If you are getting separated from the group when drift diving, then you need to kick a little. If they are hugging the bottom the current is slower.
This is an important one... that inexperienced people don't understand and experienced divers do intuitively.... Be like a bird or a fish... Have you ever seen birds standing on the beach? They all face the same way? Why? because they keep their nose into the wind.. same for schooling fish, they tend to swim into the current. So when a diver stops and wants to hold stationary in a current, you often have to spin around..
For example, you are drifting north, you look ahead and see something you would like to stop and look at. If you just stop and tilt your head down and look and maybe grab a rock and dump a little air... You will have a problem. The current will grab your fins and try to flip you over. There will be a ton of drag and turbulence and the diver will be kicking and flailing around trying to hold position.
The experienced diver instictively knows that when he wants to stop and hold onto something, he needs to spin around as he stops and put his nose into the current. In fact, if you are just a slight bit heavy and you assume a head down position, and hold your body kinda straight, you will be like a wing pointing down and the current will push you down toward the bottom and help to hold you stationary. you want your head down.
Conversely, if you stop, spin around and face the current, but keep your head up and fins low.. what will happen?... the currrent will tend to get under your belly and you will be like a wing again, but this time it will be trying to lift you up and pull you away from the bottom. You will be "floating up", even though you dumped air and were neutral when you were drifting..
So it is simple, when you stop, face the current, be streamlined, not sideways, keep your head down and the closer you body is to the bottom, the lower the drag. The current will not slow down much 2 feet off a smooth bottom, but if you get your belly 6 inches from the bottom, the current will drop off a lot.
I was watching this video with my son the other day and I commented on the exact thing that I am talking about... In this video we are drifting with the current from the right toward the left. We are drifting and swimming with the current. When he shoots a fish at around 1:00 in the video, he just instictively spins around to face the current and remain stationary while he deals with the fish. I complimented him on it when watching the video and he just laughed and said "doesn't everybody do that"?... The answer of course is NO.
On this day the current was really pretty mild, but I thought it was a decent example of what i was talking about.
7 10 12 Ft Pierce scuba spearing - YouTube
