Strobe dropping?

[Akimbo]

But it fails regularly?

Yet, in contrast, specific 'recreational' line laying approaches very rarely fail. Even with much, much thinner lines.

Doesn't that indicate an inappropriate solution?

Total nonsense, you watch too many movies. Severed umbilicals are incredibly rare. I know of one in over 50 years. The saturation diver's umbilical was fouled on a subsea manifold when the ship's DP failed and drug the bell. Amazing story though, the diver survived. The combined tensile strength of a diver's umbilical is high enough to tear a body apart.

Edit: Umbilical severed at 80 meters in North Sea

 

[Saniflush]

As someone who is not yet trained in this area but plans to be one day, I have found this whole discussion very enlightening. Thank you.

 

[kensuf]

I got a new trilam drysuit last summer. I took it to the local quarry and dived it to make sure it was "good". Then, I went to NC for a couple of days of wreck diving there.

My second dive, I was swimming through a wreck taking pictures with my new camera rig. I swam through a really big hole in a bulkhead at one point. Apparently, I was not maintaining perfect trim and I gently bumped into the bottom of the hole with the front of my thighs. I didn't think anything of it at the time (other than "oops, try and hold better trim"). When I got out, my suit was flooded. I had about a 1/4" cut in the front of my suit's thigh.

I have little experience laying line inside a wreck. Is it really so hard to imagine that a #36 line laid in a wreck could inadvertently get cut relatively easily?

ps. when I do lay line, I do generally attempt to keep it somewhat taut - as I was trained. Not piano string tight, but not saggy.

When installing a guideline into any overhead environment you should be actively engaged and paying attention to where you are installing it. That means paying attention to the objects you do a wrap, placement, or lay the line against. I would hope that the awareness of each diver while installing the line would prevent them from laying a guideline against sharp objects in such a way that it gets cut, and I would argue that if someone was oblivious to where the guideline is being installed, then they probably do not belong in that environment.

 

[DevonDiver]

Total nonsense, you watch too many movies. Severed umbilicals are incredibly rare. I know of one in over 50 years.

I was referring to your comment, back on page 3, where you said:

"Probably because we see a lot of failed line due to abrasion as well as exceeding loads".

 

[DevonDiver]

Is it really so hard to imagine that a #36 line laid in a wreck could inadvertently get cut relatively easily?

Why imagine, when you have experience to draw upon?

I've got spools and reels that are still holding and using #36 line for the last decade....literally thousands of penetration dives. Not severed... not even particularly quick to wear out.

Properly laid, there shouldn't be any movement on tie-offs that causes abrasion, nor any force applied on the line that'd come anywhere close to severing it.

If a line were severed, 99% it's a skills failure, not an environment issue.

Nonetheless, it'd be imprudent to rely solely on a guideline.

Even if the chance if a severed line were extremely remote... and protocols exist for line searches in this scenario.... the consequences of losing your timely exit from the overhead are too severe for other methods not to be supplemented into the approach used.

 

[Akimbo]

I was referring to your comment, back on page 3, where you said:

"Probably because we see a lot of failed line due to abrasion as well as exceeding loads".

Sorry if anyone thought that line = umbilical. Not the same at all. Umbilicals are a bundle of hoses and cables between the surface or bell and the diver. As a minimum they typically include breathing gas supply (about 10mm or 3/8" ID), communications (voice minimum but usually TV and lightiing as well), and a pneumo hose to precisely monitor depth. Sat umbilicals usually include an exhaust hose so gas can be recycled on the surface.

Line, as mentioned before, is anything between twine (more than thread but not much) and hawsers (2"/50mm or more in diameter). Rigging is a fundamental skill used on every dive. The concept of laying taught lines to reduce (not eliminate) chaffing is nothing new to commercial divers. We see a lot of broken lines and cables because we constantly rig heavy tools and loads at sea.

 

[DevonDiver]

Sorry if anyone thought that line = umbilical. Not the same at all....
Line, as mentioned before, is anything between twine (more than thread but not much) and hawsers (2"/50mm or more in diameter).

I don't quite understand what you're saying.

You said you broke lines regularly... and that line practice/approach stemmed from your experience in commercial diving (using umbilicals).

I took that to mean that you laid guideline on recreational dives using habits developed when commercial diving with umbilicals?

My response was along the lines of it being a bad cross-over of techniques... as most we'll trained and proficient recreational wreck divers will never see a severed guideline, even when using thin #38 line, let alone a super-thick line.

 

[RobertL]

I took Adv. Wreck with John and take deeply to heart his message to use every possible means, which includes strobes, lines, deck plans etc. to maximize the probability of a safe egress. Total dependence on one method is simply foolhardy. During our training, following the line in blackout mask, my buddy just came up with a free end of line. When we went back to get the reel, the line had been cut and the reel stolen! So yes, running lines is a good thing but it sure isn't everything.

 

[Schwob]

the line had been cut and the reel stolen!

To those who do that sort of thing:
Miserable jerks!