Safety stop w/o anchor-line

[rr75]

Hi everyone:

This may be a dumb question, but I'll ask it in the spirit of "the only dumb question is the one you didn't ask...":

I've done 15 dives, most from a boat, but recently starting relatively shallow shore dives in the 35-50 foot range. When I was shore diving today, visibility wasn't great...a few feet at the end...enough for me to see my buddy and not much else. We ascended slowly and stopped for our safety stop. We managed to hold somehow at 15 feet for about 90 seconds, but then drifted up a bit, then descended a bit, but then a bit too far (20-ish feet), then back to 12, and around there. We did that for 3 minutes and surfaced with no issues.

I'm wondering...is there an easy way of holding at a depth for a safety stop without an anchor line or even a visual reference (other than my buddy)? Our buoyancy at the bottom was fine...we were down for 40 minutes without issue. It seems we botched our buoyancy in the end, or it might have been that our tanks were more buoyant. For full disclosure, this was in the Pacific, with a bit of surf, a bit of surge, wearing a 7-mil wetsuit...with about 5-10 feet of visibility.

Definitely appreciative of any ideas out there. Thanks a bunch!

 

[jbd]

just fine at this point. Granted you wandered about a bit but the important thing is that you were trying and you were aware.

What you need to work on now is refining your awareness so that the departures from the desired depth are only 2 or 3 feet before you take action to correct. hopefully you were able to correct your depth with lung control instead of inflating and deflating your BC.

In calmer waters there is usually something small floating in the water that you can use as a reference point. Practice with something like that. We are talking about plankton or algae.

In surge and currents things can be more difficult but it can be done with practice.

I believe you are on the right track.

 

[ERP]

I watch the water or rather the itsy bitsy stuff in the water, it's not too hard to get a feel for your rate of change of depth with some practice.

FWIW I find it easier in relatively low vis than I do in clear blue water.

 

[drbill]

Keep in mind that bouyancy control near the surface is more difficult due to factors like the added bouyancy of you wetsuit since it is no longer compressed like it is at depth, the added bouyancy of your nearly emptied tank, water motion in the upper water column from surge and swell, etc.

Where I do most of my dives I can easily accomplish my safety stop by hovering just above the rocky bottom at 15 ft. Doesn't sound that is possible where you are.

Dr. Bill

 

[JHAM]

With experience you will get more control over boyancy even with out a refference point to watch.

When diving from a boat this can be an inportant skill to master. You never know when you wont be able to find the line. Or sometimes the mooring breaks leaving you with no line. This is rare but it does happen.

However, I feel the easiest way to ascend with out the anchor line is to provide my own.

In open water I carry a small reel and a SCUBA tube. When forced to ascend with out the aid of a line, I simply blow up the SCUBA tube and let it fly to the surface carriing my reel line. I then can reel in the line using it for a refference. It's tough to operate your reel and watch your guage at the same time. Your buddy should take some of this work from your hands.

When doing this technique you should be cautious of current. When you do reach the surface you could be pushed quite far away from your boat!

There is another method of using a reel to ascend which involves attaching the reel line to the wreck and doing a sort of reverse of the method above. This will allow you to not wander too far away but there is a mojor down side.... When you get to the surface, you must cut the line. But what the heck line isn't overly expensive, and it will get you to the surface safely.

If you decide to get a reel and tube, I highly recommend you practice ascending with it in a safe, controlled environment before you really need to in open water.

 

[Arnaud]

Well, it may say 15ft in the book, but it can be a little more. If the conditions are not good, try a few feet deeper. It may help.

You also may want to try and practice being horizontal, and not vertical. This should help.

Watch your breathing. Your pulmonary system is your very own BCD.

Obviously, your depth gauge or computer is here to help, but it may lag a second or two. Be aware of your ears. They're a good pressure indicator, at least on descent.

For the rest, practice. Experience can't be had overnight. When you have an anchor line near you, try not to hold it. Just use it as a reference point to practice and improve your buoyancy.

 

[DA Aquamaster]

A saftey stop does not have to be 15 ft, anything bewteen 15 and 30 is fine. I agree with the suggestion of watching the little stuff in the water in limited viz conditions to determine if you are rising or falling.

Personally, I will often shoot a lift bag to serve as an ascent line in limited viz and this allows you to remain just a bit negative at the stop depth and hang off the bag. It takes the work out of hovering at the stop depth in little or no viz and makes it easier for all the divers in the group to stay together. So I carry a reel and lift bag on every dive on the off chance we will have to ascend before reaching the anchor line.

Using an upline is also a workable idea, but generally speaking you should not be using a wreck, cave or saftey reel with braided nylon line to do this. That stuff lasts forever in the water and the piece you inevitably have to cut away becomes an entanglement hazard for future divers.

If you plan to use an upline, you really should use a jersey reel with 1/4 sisal or hemp line on it. It's cheap, biodegrades fairly quickly and is less of an entanglment threat to others. Of course the stuff also rots on the reel if left wet so you need to make sure it gets dried between dive days or one day you will unreel it in a situation where you need it and find the line under the first few layers black, rotten and unusable.

The only situation where you really need an upline and a jersey reel as opposed to just shooting a lift bag with a regular reel is in a current. The upline is tied to the wreck and prevents you from drifting in the current during your ascent and saftey or deco stops. This also requires a lift bag with enough lift to keep the line on the surface in the current.

 

[SeaJay]

...And forgive me if I only serve to reiterate what other people have mentioned. Lift bags are commonly used for this purpose, and jersey lines are a great answer too. Of course, staying with the upline, or "anchor line" (same thing) is an obvious fix to the solution.

...But "free ascents" - that is, ascending with little or no visual reference for whatever reason - can happen, and will happen to you again. What's interesting is ascending from 100' of zero-vis water... Can't see the top (not even a single ray of light) and can't see the bottom... Not even if you had a telescope. It's an amazing experience (and quite a bit of fun if it doesn't scare you off), especially when there's no vertical reference at all either.

1. I find that if I stay horizontal, I have more ascent control. Not only am I able to "neutralize" current better, but in this position, my body is resistant to depth change. I travel only slowly up or down, because I don't "slice" through the water like I would if I were vertical.

2. I dive with as little weight as possible. I recommend the PADI method (outlined in your OW manual) of weighting yourself neutral at the END of the dive with an empty tank. Diving with as little weight as possible means that I'm also diving with as little gas in my BC (wing) as possible, which means that I don't have an expanding air bubble on my back which adds to my instability.

3. I use my breath to "trim" my buoyancy. A little deeper breath makes me rise, and a little deeper exhale makes me fall.

4. My guages are on my right wrist. This allows my left hand to remain free to operate a light (for the guages), and operate both dumps (lower left, and also on the end of my corregated hose). I dump early and maintain buoyancy with my lungs (don't hold your breath!)

So the keys are: Horizontal trim, as light as possible, guages on the right wrist, and all dump/inflator mechanisms operable with one hand.

In heavy swells, I'll shoot to stay a little deeper than normal to avoid the motion of the waves.

...And yes, if you're focused on your guages, you can maintain perfect depth without an ascent line with ease. Just keep an eye on them and control your ascent with your breath.

By the way... I don't want to sound like a broken record, but I recommend the DIR Fundamentals book which touches on this subject pretty considerably.

 

[dlegros]

SeaJay once bubbled...

2. I dive with as little weight as possible. I recommend the PADI method (outlined in your OW manual) of weighting yourself neutral at the END of the dive with an empty tank

<SNIP>

By the way... I don't want to sound like a broken record, but I recommend the DIR Fundamentals book which touches on this subject pretty considerably.

Unbelievable!

A post saying something positive about PADI that also recommends DIR.

Do mine eyes deceive me?



Dom

 

[DA Aquamaster]

SeaJay once bubbled...
...And yes, if you're focused on your guages, you can maintain perfect depth without an ascent line with ease. Just keep an eye on them and control your ascent with your breath.

I agree with Sea Jay on this with the exception that the emphasis should be on focusing on the little particles in the water column to determine trend and rate of movement while referring to the gauges occassionally to ensure you are maintaining the correct average depth.

You will rise and fall a little with each breath and referencing the water around you is the best way to ensure the ups equal the downs. The reaction time and limited sensitivity on most depth gauges prevents you from using them with the same precision. Gauges give good overall information but rates and trends are better observed through more direct means.

I also agree that over weighting is the root of most bouyancy problems. I was asked to buddy up with a relatively inexprienced advanced class diver on a pair of deep dives dive last weekend. She did very well on the first dive but reported to the instructor that she had some trouble getting down. He then added weight to "fix" the problem and on the second dive she was badly overweighted. She could not get off the bottom at 105' without assistance, had trouble with the entire ascent and without an ascent line would have blown the saftey stop due to the large amount of air she was having to manage in the BC.

I like this instructor and dive with him a lot outside of training situations, but teaching his students to weight themselves properly is not one of his strenghts.

The instructor did her absolutely no favor by just adding more weight rather than further exploring her report problems getting down to determine if or why a problem existed.

I like to do ascents and stops even through mid water solo without an ascent line as it is less bother than shooting a bag. But with more than one other diver in the water, I have found it is much easier to keep the group together in low viz if I shoot an ascent line.