What do you do when the anchor line breaks free?

[johndiver999]

No, that's a separate issue. It wasn't pulled under by people on the line, it was from the current. We weren't using the line to compensate for buoyancy, we had to be neutral to hold our stops, which is what we were doing.

I guess there is probably some sort of physics and geometry equation to figure this out, but I would think that for the SMB to be at 40 feet it would either have been launched incorrectly (i.e. tied off before it hit the surface), or you were diving in the Niagra falls basin!.

So if you launch the SMB correctly, it will hit the surface. Then when you tie it off, it can get pulled down in current, but not 40 feet. But I guess if that happened, you would need to launch your second SMB from there!

If you are holding on the line in the current, then it pulls the smb downward, it is physics. If nobody is hanging on the smb, it will probably stay on the surface because the drag is low. You get three divers on the line, the drag goes up immensely. The drag component sinks the smb.

I've seen a diver trying to climb a line like that in a strong current and it just pulled a large float under and then he inflated his BC more and it pulled him deeper, and then he filled the BC more and continued to get pulled deeper (when he wanted to ascend)... then he fully inflates BC and tries to kick up, and still won't rise from like 35 feet.... then he did what I knew he would (and feared) - let go. Poor guy got a delivered to the surface pretty quick. It would have been humorous if it was not potentially fatal.

 

[BlueTrin]

Which PLB do you use out of curiosity? (You say you have a GPS device)

 

[Celt]

Good point!

Tie ins have a few weaknesses, the grapple doesn’t always fall in the perfect spot and you may not have the slack to move. Skippers believing the anchor is tied in will haul the slack putting more strain on the tie. When the tie goes the anchor has no hope of grabbing the wreck the second time unless there’s a large piece of wreckage in the path of the grapple.

 

[beldridg]

In Southern California, we rarely "hard tie" into wrecks unless there is a permanent morning ball (e.g., the HMCS Yukon in San Diego). Especially on deep wrecks, we use down lines.

The "benefit" of the downline is that it is easy to deploy (and even easier than a tie-in to retrieve). The downside is that it is not guaranteed to be on the wreck and, in very heavy current, it can move off the wreck (we had this happen a week ago on a 250 fsw deep airplane wreck).

It also requires the divers to be fast and proficient on getting into the water and to not pull the line off the wreck on the way down.

If I follow your description correctly, I do have one question: how did you retrieve your SMB which was (presumably) hard tied into the wreck? Did another diver go back down and retrieve the line?

- brett

 

[mje113]

Tie ins have a few weaknesses, the grapple doesn’t always fall in the perfect spot and you may not have the slack to move. Skippers believing the anchor is tied in will haul the slack putting more strain on the tie. When the tie goes the anchor has no hope of grabbing the wreck the second time unless there’s a large piece of wreckage in the path of the grapple.

Feel free to discard this comment as I'm fairly new to this kinda diving but I've been on this boat a few times and I've never seen a grapple. They tie in with a diver wrapping some pretty thick chain half a dozen times around a part of the wreck.

The diver (who's part of the crew) then sends up a plastic bottle to let the skipper know it's tied in.

 

[doctormike]

Great write up.

Question: Did your buddy use a jersey upline to tie his SMB to the wreck, which if I understand correctly he would then have discarded. Or did he use a different method? I am just curious if he was able to retrieve his line once you surfaced or if he tied it off knowing he would cut the SMB free and leave the line. I know there are different methods people use such as looping the wreck and then pulling up the line afterwards.

Jersey upline not in use much any more. Yes, the idea of looping the line was brought up in the other forums. I was trained to do that, but I wouldn't' do that now. It seems like a great idea, but if you don't tie it off, having the line moving over sharp rusty metal is a good way of having it break, and that's a problem, especially if you have deco to do.

One variant of that would be to shoot it, give it some time to pull the scope, then tie it off and THEN ascend with the reel. That way you have redundant ascent lines,, both tied off at the bottom, and you take your reel with you as you ascend the first line. And there is no line rubbing on sharp metal.

The classic Jersey upline used Sisal, which was biodegradable...

 

[MaxBottomtime]

I have to ask. You were on a rebreather and had 23 minutes of deco after 30 minutes at 115 feet?

 

[doctormike]

If you are holding on the line in the current, then it pulls the smb downward, it is physics. If nobody is hanging on the smb, it will probably stay on the surface because the drag is low. You get three divers on the line, the drag goes up immensely. The drag component sinks the smb.

I've seen a diver trying to climb a line like that in a strong current and it just pulled a large float under and then he inflated his BC more and it pulled him deeper, and then he filled the BC more and continued to get pulled deeper (when he wanted to ascend)... then he fully inflates BC and tries to kick up, and still won't rise from like 35 feet.... then he did what I knew he would (and feared) - let go. Poor guy got a delivered to the surface pretty quick. It would have been humorous if it was not potentially fatal.

Gotcha, that makes sense!

 

[doctormike]

I have to ask. You were on a rebreather and had 23 minutes of deco after 30 minutes at 115 feet?

Gotta say, I was surprised about that myself! You can see I got a little sloppy at points on the ascent... Left the bottom at minute 36, cleared at minute 59.

30/70, setpoint 1.3 on the bottom.

 

[doctormike]

Which PLB do you use out of curiosity? (You say you have a GPS device)

Nautilus.