Currents & Wrecks (split from SG incident)

[Gombessa]

which still isn't right. *always* run a line from open water, always always. Never underestimate what panic/stress can do to you on a hard exit from a cave. even if open water is only 3 feet away, always run the line.

Maybe this is more of a Q for the tech forum, but I've had a diver tell me about nearly getting "sucked into" a wreck or cave in a current strong enough to nearly blow off his mask. Is this a real possibility (rare or otherwise)?

If so, it seems to add support to the "conservative" practice of always running a line to open water even if you only intend to go in a few feet.

 

[Rick Murchison]

... I've had a diver tell me about nearly getting "sucked into" a wreck or cave in a current strong enough to nearly blow off his mask ...

Water is dense. Moving water is powerful. As any commercial diver will tell you, portholes and pipes and drains and such can easily break your body or kill you. You can do the math, but it doesn't take much velocity or pressure differential for water to have a superhuman "grasp."
Here's a little video of a crab that got a little too close to where a saw was cutting a hole in a pipe that's at a lower pressure than the surrounding water.
Rick

 

[Gombessa]

Here's a little video of a crab that got a little too close to where a saw was cutting a hole in a pipe that's at a lower pressure than the surrounding water.
Rick

All I can say is :11:. Reminds me of an old video of some poor aircraft carrier crewman getting sucked into a Harrier.

2700psi is like tank pressure--next time I'll double check the connection on the yoke valve lest some pesky crabs squirt out at the surface.

 

[heliflyer]

Yeah, but the crewman survived amazingly, I don't think the crab had a chance.

 

[uspap]

Rick
That video was wild. Are there any signs that would indicate a condition like that? If you're on a wreck do you avoid swimming near port holes?

 

[Rick Murchison]

Rick
That video was wild. Are there any signs that would indicate a condition like that? If you're on a wreck do you avoid swimming near port holes?

Sometimes. Depends on the conditions - if there's a strong current or surge then they can be quite dangerous, and it's a good idea to just avoid 'em.
Rick

 

[Thalassamania]

we have a hole like that and now its all ruptured and jagged as of about two weeks ago....

somebody will swim by and get raked

wow, some article about the recovery.

Then there’s that great lava tube (the toilet bowl) we used to snorkel up at Hanauma, what a rush.



Cath, time for intentions again eh?

 

[Missdirected]

That is a little rough of a comment, I knew two of these men. Keep is respectful, they have passed. You should use this as a learning experience, not to puff up your own chest.

What comment are you referring to :huh: Just to be clear, the last couple of posts are referring to video link, post 430, posted by Rick Murchison, no reference to the men who died.

 

[String]

Maybe this is more of a Q for the tech forum, but I've had a diver tell me about nearly getting "sucked into" a wreck or cave in a current strong enough to nearly blow off his mask. Is this a real possibility (rare or otherwise)?

Its possible and depends on the place where the wreck is, its angle to the normal current, tidal strength etc. Some wrecks would never get it, others have a reputation for it. Shallow wrecks with surge are particularly prone for it.

There is a wreck in Portland harbour which has a reputation for being one to get sucked into. You cant dive it any more for political reasons anyway though.

If so, it seems to add support to the "conservative" practice of always running a line to open water even if you only intend to go in a few feet.

Lots of people do. However some "suck ins" happen to a diver just diving past on the outside so they're in it without wanting to be and without time to line lay. The other problem is you may have a line to get out but could be too much of a current to go back out.

 

[rawls]

It happens. Sometimes the surge around a wreck is pretty strong. I got slammed into a wall last Summer from surge.