Swim throughs - what could possibly go wrong?

[drrich2]

The comment on recreational Wreck Diving doesn't train you for penetration is kind of missing the point....it is not a penetration course, it is about diving near and on wreck's not in them.

From what I understand, with the PADI Wreck Diver specialty, there's an option to do a penetration dive for one of the required dives, and the course content does consider penetration.

I don't believe one needs to be certified just to dive near or on (most) wrecks (I imagine there are exceptions, with entanglement hazards on the surface, etc...). I've dove a few wrecks on vacation, and have yet to have an op. ask about wreck diver certification. AOW due to depth, yes, but not wreck certification.

Richard.

 

[tursiops]

From what I understand, with the PADI Wreck Diver specialty, there's an option to do a penetration dive for one of the required dives, and the course content does consider penetration.

I don't believe one needs to be certified just to dive near or on (most) wrecks (I imagine there are exceptions, with entanglement hazards on the surface, etc...). I've dove a few wrecks on vacation, and have yet to have an op. ask about wreck diver certification. AOW due to depth, yes, but not wreck certification.

Richard.

The PADI course sensitizes you to looking for points of interest and points of hazard, and gives you some practice in sketching out a wreck to get ready for your next dive on it. Those are all good things. Dive 3 gives you some practice on running a reel, which is usually a brand new skill for most folks, and not as easy as it might look. Dive 4 does have the option to do a very limited penetration, with a reel, staying in the light zone, kind of like a baby cavern dive. But there is not enough training on the previous dives to do it very well, and few wrecks ares such that it works out. The classic "swim through" is not the right thing, but passing through hatches into an engine room is not so good either! As a result, it is an option on dive 4 but I think rarely exercised. In any case, if all you know about penetration is what you get on dive 4 of the PADI course, you'd be crazy to think you are now ready to go penetrate a real wreck. If nothing else, you have no redundancy.

I've taught the Wreck specialty a number of times, using the Hilma Hooker in Bonaire for Dive 4. With the better students, we've done a very simple penetration, but it always makes me nervous. The last time, I was inside the engine room with a student and a whole crowd of divers arrived and just swam in and stirred up all the silt we'd been so careful about. The poor student had to retrieve his penetration line in about 1-foot viz.

The best thing about the Wreck class is it makes you aware of the hazards and tries to keep you from killing yourself...or others.

 

[Foxfish]

Here is an example of the kind of this I was looking for:

Risk: BCD overinflated. Diver pinned to roof of overhead.

Mitigating:
Ensure that you have adequate weight in your BCD for all depths and with the tank near empty. If anything be slightly over - weighted.

Be sure that you are competent to dump the BCD contents from different locations on the BCD.

Diver needs to have the confidence and experience not to panic if this occurs.

If the BCD inflator jams on, disconnect the LP hose. Exhaust air and gain proper buoyancy.

 

[waterpirate]

If you leave your mind fully open, people will fill it with garbage. That is generally what you get from open discussions on te internet.

A quick history lesson will show you that diving is not getting more risky. We know and share more info now then ever before. That is why there is now a clear path via agency training to train you all the way to 300fsw+. Ignoreing that path may be harmfull to your health.
Eric

Today we owe our safety and comfort to those who went before us. We are truly standing on the shoulders of giants, some who paid the ultimate price. To ignore the path that they pioneered and made safe for others to follow is not wise.

 

[Subcooled]

Here is an example of the kind of this I was looking for:

Risk: BCD overinflated. Diver pinned to roof of overhead.

Hey, that happened to my friend. He was diving a set of double tanks, a steel backplate, and a wing. A first stage free flow occurred, inflating his wing, pinning him in an A-shaped crevice in the roof. He was buoyant and thus unable to escape the hole. He was also unable to reach the valves. There was some rock around to prohibit that. And his regulator was free flowing. He needed the help of his buddy. An interesting situation, I must say...

An alternative escape might have been possible once both tanks had been emptied.

In situations like these you really want a buddy that can relax, smile, and then do something usefull. I am not quite sure that such a confidence is possible without the reassurance of past solved problems. Did I just say that it is good to have experienced a myriad of small incidents in safe settings?

Dropping ones weights in the wrong place may also be less fun.

 

[Foxfish]

Hey, that happened to my friend. He was diving a set of double tanks, a steel backplate, and a wing. A first stage free flow occurred, inflating his wing, pinning him in an A-shaped crevice in the roof. He was buoyant and thus unable to escape the hole. He was also unable to reach the valves. There was some rock around to prohibit that. And his regulator was free flowing. He needed the help of his buddy. An interesting situation, I must say...

An alternative escape might have been possible once both tanks had been emptied.

In situations like these you really want a buddy that can relax, smile, and then do something usefull. I am not quite sure that such a confidence is possible without the reassurance of past solved problems. Did I just say that it is good to have experienced a myriad of small incidents in safe settings?

Dropping ones weights in the wrong place may also be less fun.

I find it hard to conceive how you could float to the top of an overhead environment with an over pressurised BCD and not be able to reach either your inflator to disconnect the hose or one of three dump valves with one of your hands. Unless of course you were crawling up into a very tight space in the cavern and this occurred.

On this forum I think it is safe to assume that you have a buddy and both have suitable qualifications to be diving in the environment. If so, how would you avoid or resolve the problems you described.

 

[Subcooled]

I find it hard to conceive how you could float to the top of an overhead environment with an over pressurised BCD and not be able to reach either your inflator to disconnect the hose or one of three dump valves with one of your hands. Unless of course you were crawling up into a very tight space in the cavern and this occurred.

It is quite an amazing feat, isn't it? I have no idea how he managed to do that. But he had to be rescued by his buddy. If you can't reach the inflator hose to disconnect it, then operating a dump valve pointing downwards isn't hugely effective. Yes. It was a natural cave and a narrow crack in the roof. I wasn't present, so I just tell what he told me. I don't know what went on in his mind during that time. In a stressfull and unexpected situation even obvious solutions seldom are so obvious for the distressed. He had got decent enough cave training, by the way, as so did his buddy, and so he lives.

 

[kwinter]

I don't get it. Swim-throughs, caves, wrecks, overheads. What's the attraction? Why would any guy be willing to take a risk to go into a tight, dark, wet place?





Oh, wait a minute..............




Please pardon any typos. Sent from my iPhone using Tapatalk

 

[tursiops]

A first stage free flow occurred, inflating his wing

?? How does this happen? A first stage free flow isn't going to cause a LPI hose to free-flow....that depends on the inflator mechanism itself.

 

[Lorenzoid]

What do you guys who stick to the no overhead ever theory do in places like Cozumel where almost every dive has a swim thru? Do you leave the group and go above? Do you tell the dive guides that is inappropriate and unsafe to take rec divers thru these? Just curious?

This got at least one comment in reply, but it's such a common question I thought I'd add my two cents. First, there have been many threads/posts on this issue, since a lot of us North Americans are most familiar with coral swim-throughs through our trips to Cozumel. What I do is ask the DM about swim-throughs in the pre-dive briefing. I tell him I'd like to make up my mind when I see the swim-through, and that there needs to be an alternate path over or around it if I decide to avoid the swim-through. By doing this, at least he will know where my buddy and I went. Preferably, when I get there I signal him that we're going over/around it. As I said recently in another thread, I think the best thing an OW can do is to remember that it's okay to ask the DM in the pre-dive briefing about swim-throughs and state your questions and concerns and get the answers you feel you need. There is no shame. You will NOT look like a wuss.

My criteria for swim-throughs is that I won't do any that are narrow or through which I can't see a big expanse of daylight. If it looks like more of an arch than a swim-through, that usually looks safe enough for me. My usual dive buddy (wife) and I are in agreement as to the criteria and as to what we do when we encounter a swim-through.

I'm ambivalent about relatively shallow wrecks where a feature, like the wheelhouse, has been opened wide up, presumably to make it "safe" (in someone's opinion) for OW divers. I generally do not swim through them. But seeing dozens of OW divers swarming through them without getting into trouble, and knowing that this goes on day after day when I'm not there, does make me wonder if I need to be as conservative as I am.

As others have pointed out, like every other aspect of diving, you have to weigh the risk, and hopefully there are enough statistics that we can get some grasp of how risky a particular aspect may be. Divers don't appear to be getting into too much trouble in Cozumel swim-throughs. If anyone has any statistics to share, please do.