Safety Stop Question

[gary_b]

Hey Guys!

We often dive from my boat, often in depths around 20 - 25M.
Where we dive there is often fairly strong currents and swell so the boat swings around at anchor a fair bit (and we are pretty average at underwater navigation). So often on our safety stop one of us will surface, have a look for the boat and then re-join the rest of us.

My question is: Does this defeat the purpose of the safety stop for the guy who surfaces to look for the boat, even though they come back down and do the stop?

Cheers!

 

[xmass-Eve]

I don't think so if they just go for a quick look. Anyway, a safety stop is only recommended so it doesn't matter if it was...

 

[gary_b]

Thanks, Didn't think it would matter too much. Was just wondering about it the other day, mind you we've been doing it for years and had no incidents thus far..

 

[Johanan]

Why don't you just follow the anchor line?

 

[gary_b]

When I can find it i do, but often the vis here is poor, so its easy to miss and there is not allot of distinguishable terrain to use in visual navigation.

 

[northernone]

Popping up and going back down likely is worse than simply a slow ascent and no stop.

As mentioned, the safety stop is optional, but it's important to remember it's purpose.

(Edit: see the post @boulderjohn) Going back down would be incomplete and unnecessary in water recompression, possibly increasing the risk of being bent. The other way to think of it is a short shallow second dive with very little surface interval.

The safety margin built into dive tables allows for quite a lot of behavior that hypothetically would be damaging, but most of the time is harmless. I think popping up and immediately diving again is one of these examples.

Regards,
Cameron

 

[JamesBon92007]

I'm in agreement with northernone on this. Why not just ascend to 15 feet for 3 minutes and then surface to look for the boat?

 

[gary_b]

I'm in agreement with northernone on this. Why not just ascend to 15 feet for 3 minutes and then surface to look for the boat?

I'll probably start doing this. Normally when one of us pops up to scope out the location of the boat and comes back down, they then point us in the direction of the boat and we then swim at 5M / 15ft towards the boat, that way once the 3 mins is up we're pretty much at the boat. We are always really careful with regards to ascent rates etc.
But yeah, I guess I'd never really thought about it 'till the other day..

 

[SoFlaDiver954]

If your boat is anchored, it can't be that far from where it started, even if winds or current shift a little. A little navigational awareness during the dive will probably go a long way toward helping you surface near the boat. You could also put a strobe on the anchor line to make it easier to find at the end of the dive.

In any case, I wouldn't surface to look for the boat then go back down for a safety stop. Why not shoot a bag and have whoever is manning the boat follow your marker and pick you up?

You do have someone manning the boat while you're underwater, right? Not doing so is more of an issue than blowing a safety stop.

 

[boulderjohn]

Going back down would be incomplete and unnecessary in water recompression, possibly increasing the risk of being bent.

I am going to disagree with this a bit, first with the terminology. In water recompression (as is being discussed in a couple threads right now) occurs when a diver has surfaced, displays DCS symptoms, and redescends to follow some sort of IWR protocol, hopefully with proper equipment and a trained attendant. What is described here is called omitted decompression by the technical diving agencies I know and the US Navy, and they describe the proper procedures, depending upon the situation. The systems I know do recommend redescending and completing the missed stop, sometimes adding extra time.

Here is Steve Lewis's explanation of the difference.