Back Roll and a Flip?

[Mossman]

During our Rescue class we did back roll offs from the moving Inflatable, one team at a time, first team with no buoyancy, and second team immediately on their heels with full buoyancy.

Results in one submerged team and a second team just above and to the front of the first team. A 4 "man" search pattern results, and was a heck of a lot of fun to do!

It took some practice, with teamwork and timing to get it right, but it was dam sure a lot fun learning to do these entries!! Boat is not moving at a high speed during such entries, obviously!

Moving at high speed or not, I assume there's a propeller spinning pretty fast?

 

[gypsyjim]

Moving at high speed or not, I assume there's a propeller spinning pretty fast?

True. You do need to be somewhat experienced at the backward roll off entries, but :

1) By the time you reach Rescue you should have a bit of experience, and when we first started practicing this skill it was not from a moving boat, and prop was not active.

2) If any diver in the group did not seem to comprehend the need to move to the side I am sure our practice would have been adapted to teach such an important skill.

3) Remember, this boat is moving forward, and even at our low speed the diver would nearly have to try to contact that prop, as he or she has dropped @3 feet to the side, and the boat is passing away from the diver instantly, BUT, while the boat may be continuing forward the diver will not be. The instant the diver contacts the water all forward motion is going to stop.

(Unless we should be trying to 'skip" divers like flat stones, by trying this maneuver at high speed, in which case of course injuries would be guaranteed anyway!)

I am really not sure a diver could even reach the prop of the moving boat deliberately during this maneuver if they wanted to, before it was beyond their reach. This is one theory/question I think I will pass on testing tho.

 

[Diver0001]

Just a silly question. I've got 25 dives logged in total, a number of them have required back rolls off the boat (in very deep water). After rolling off the boat, when I hit the water, I have found it natural to continue the backward rotation and complete a 360 to get vertical again.

Is that odd? Ive never asked anyone to observe me, but I'm wondering if I might be hitting the water head-first instead of on my back.

Do you do it my way or do you stop rotation when you hit the water, then rotate forward 90 degrees to get vertical? Does it matter?

On the whole I don't think it really matters much provided you don't roll under the boat in the process. I'm not sure you'd be able to get away with it consistently while wearing a drysuit though. I don't know if that's in your future, but the thought crossed my mind.

R..

 

[Dannybot]

I just follow through with the back roll. I imagine one could stop the rearward momentum and reverse direction, but why bother.

 

[TMHeimer]

Interesting question. I think I've done it both ways. To be honest, I've never given it any thought. As long as everything goes smoothly and I wind up on the surface with my head out of water ready to descend that seems to be OK. Now I have something to think about....

 

[Steve50]

continuing the roll can result in hitting your head on the bottom of the boat, depending on the boat and it's movement due to wind etc.

 

[Doc Harry]

Q: Why do scuba divers do a back roll from the boat?

A: Because if they did a front roll they would still be on the boat.

 

[Bombay High]

Moving at high speed or not, I assume there's a propeller spinning pretty fast?

I do not think I would do a roll off a moving inflatable with outboards spinning and submerged. Even if the odds are slim, they are still there.
I saw a Filipino diver get his face carved up completely rolling off a Zodiac in Goa during a salvage operation of a ship that ran aground in the monsoon. We had to hold his face together as we rushed him to the base. He was back 2 weeks later looking like a baseball with all the stitching looking more like a cobblers work than a doctors.
Luckily he wasnt very pretty to start with

 

[lsorenson]

Is that odd? Ive never asked anyone to observe me, but I'm wondering if I might be hitting the water head-first instead of on my back.

Alot of it will have to do with how high your out of the water when you roll... If your in a large boat and in swells, you time it wrong and you can have a substantial fall... I can also see where air in your BC could force you to do a 360...

Me, I always do negative entries so no to the 360's....! lee

 

[gypsyjim]

I do not think I would do a roll off a moving inflatable with outboards spinning and submerged. Even if the odds are slim, they are still there.
I saw a Filipino diver get his face carved up completely rolling off a Zodiac in Goa during a salvage operation of a ship that ran aground in the monsoon. We had to hold his face together as we rushed him to the base. He was back 2 weeks later looking like a baseball with all the stitching looking more like a cobblers work than a doctors.
Luckily he wasnt very pretty to start with

I have a question about the accident you described above:

Was the Zodiac in Goa moving forward, as in our search and rescue exercises, or was it halted, with the prop engaged, while divers were in the water? THAT would make huge difference in risk factors.