Diving Thoughts

I have a borrowed OMS twin tank wing, whose power inflator was sticking open, so that when I pressed the button to inflate the wing, it would continue pushing air into the bag even after I’d stopped. The only way I could dive it was to disconnect the inflator hose and inflate it orally when necessary.

As a reminder for next time, with the usual caveats of “Don’t try this at home” and “this may not be the right way to do it”, and “Don’t come crying to me if it all goes horribly wrong”, here’s how I fixed it.

1. Take the inflator valve off the wing’s hose.

2. The air intake nipple doesn’t have a hexagonal nut to unscrew, so use a pair of pliers to unscrew the nipple, having wrapped them in cloth so as not to damage the metal.

3. Then take off the o-ring from the nipple

4. There are two grooves on the inflator button, one on either side. Use a pair of snap ring pliers (circlip pliers) to grip either side of the red button and unscrew the inflator valve.

5. Use 6.5mm socket wrench to take spindle out of inflator barrel.

6. Push the pin out of “wing-end” of the plastic. If there is a fast pull-dump on the corrugated hose, this pin is to hold the wire that connects to the shoulder dump valve. This OMS one doesn’t have one, but it does have the pin.

7. Use a pair of pliers to grip the outlet valve on the end. Push a 9/16″ socket into the other end and use it to undo the nut, allowing the outlet valve to come free.

8. Take off all the o-rings and discard (or retain if you’re really short of money and they’re in particularly good condition)

9. Soak all the other parts in an ultrasonic bath for 10 minutes or so.

10. Rinse and dry all parts.

11. Get a new set of o-rings ready. Put the 2 small ones onto the spindle and grease them with silicone grease

12. Put the rest of the o-rings on and grease

13. Put spindle through inflator barrel and put spring and button on. Use 6.5mm socket to tighten. This should be hand tight.

14. Screw inflator barrel into the plastic. Don’t overtighten as you risk damaging the plastic.

15. Screw air inlet nipple (with o-ring) into plastic. Don’t overtighten as you risk damaging the plastic.

16. Put paper round the deflator button to prevent scratching and grip with pliers. Then use 9/16″ socket wrench to tighten nut, locking deflator button in place.

17. Put the pin back in.

18. Hook the the inflator valve up to a regulator on a tank and make sure that it’s working. I do this before reconnecting it to the corrugated hose in case it doesn’t work and you have to cut it off again.

19. Use a cable tie to fasten the inflator valve back to the corrugated hose and reconnect to the wing / BCD.

20. Test again with a regulator.

You’re done, but be careful with it when you take it out diving.

Seven of us were round at SCDC’s Diving Officer’s place on Saturday for an Equipment Maintenance workshop. After depositing my entrance fee (a sixpack) in the fridge, I took a look at their dining room table. The last time I’d seen it was on New Year’s Eve when it had been covered with excellent German food. Now it was covered with what looked like Black and Decker’s entire product range. There was a wide variety of tools, one or two of which I knew what to do with, and some of the others that I didn’t dare think about.

Since I was late I found that I’d missed Andreas showing how to disassemble Catheryn’s Halcyon inflator valve. But because I’ve had to clean my own out on several occasions, I wasn’t too disappointed. Continuing with the inflator valve theme, I’d brought along one from an OMS wing which was sticking open and filling the bag up every time I pressed it. Before long that was in pieces on the table and all the metal and plastic parts were dumped into an ultrasonic cleaner full of vinegar for 10 minutes before being rinsed and dried. They came out looking considerably shinier and newer. Andreas had prepared well by sending Gabi out to buy several sets of o-rings for different types of inflator valve. Using them we put the valve back together again and tested it. Not only did we not have any extra bits embarrassingly lying around on the table, but it also worked flawlessly. Hopefully this means that next time I dive it it won’t be trying to kill me.

Shortly after this Paula arrived. She took one look at all the equipment on the table and pointed out that the only things  that she had were vinegar and a hair dryer! Now was the turn of her inflator hose, this time from a Seac BCD. This had the same ultrasonic vinegar bath and new set of o-rings, and also came away working properly. And the photo on the right shows her soaking the dump valve in the ultrasonic bath.

Next we turned our attention to regulators. Several people had  brought along Apeks regulators which they were going to take apart for my entertainment. Regulators are obviously a lot more complex than an inflator valve and you shouldn’t be taking them apart unless you  know what you’re doing. And as several people reminded me – certainly not at 40 metres, where Rita and I had inadvisedly attempted to fix a free flow several years ago!

First, was David’s first stage, an Apeks XTX 200. The disassembly took a bit longer, and particular care was needed taking out the membrane to make sure the metal part it sits on wasn’t scratched or damaged. Once it was apart, the metal and plastic all went into the vinegar to be ultrasonically cleaned. Putting it back together again is more fiddly, and it’s very important to pay attention to detail and get things in the right order. One of the problems I have is telling which o-ring to use, as some of them are quite a similar size. Since Catheryn also has an Apeks regulator, she was taking a careful look at everything. Andreas asked her to be careful “because we don’t want to damage it do we?”. To which she considerately replied “It’s David’s – I don’t care!” The Apeks first stage has a clear plastic cover, so you can put a label in showing the date of service, which sounds like a good idea.

Once it was all back together again, Andreas told David that he’d be so happy that he’d be buying him a beer all year. David pointed out that one beer for an entire year sounded like a good deal.

Ben and Catheryn also disassembled and reassembled their first stages, both Apekses – a T50 and another XTX200. Unfortunately Ben had to do his twice, as just after he’d got it back together again, he remembered that he’d wanted it as a stage regulator for Nitrox with more than 40% oxygen. Consequently he had to go back and use special grease to make sure it was oxygen clean.

Catheryn and David also serviced their second stages, although by then I’d gone for a curry, so I missed the final 3 hours. What a shame!

So at the end of the day we’d seen the innards of 3 types of inflator valves, 2 different Apeks first stages and a couple of different Apeks second stages. Plus an old Dive Alert that leaked when it is connected between the inflator hose and BCD inflator valve. I’d brought it along to see if we could fix it. Unfortunately  even the ultrasonic vinegar couldn’t save it. Still as David pointed out, I could carry it in my pocket and if I needed the loud audible signal that it provides, I could just hook it up on the surface where the leaking wouldn’t matter. After all, the signal still worked, as Andreas kindly demonstrated – leaving us all temporarily deaf.

All in all it was a very  interesting and useful day. Thanks in particular to Andreas and Gabi for arranging it all. And thanks to Catheryn for the photos.

Tusa are recalling some RS670 regulators sold between May and September 2009 because of loosening of the BLC plug on the first stage. This can apparently cause a high pressure leak leading to an unstable intermediate pressure. Approximately 60 first stages are affected with the following serial numbers:

• UR600022 – UR600029
• UR600031 – UR600103
• UR600637 – UR600676
• UR600708 – UR600716
• UR600737 – UR600776

For more information, go to Tusa’s website.

You can see the results of Super STAR Network’s survey on BCDs by going to their website. It showed that 50% of respondents had had a problem with their BCD, 42% rarely and 8% occasionally. The most common problems are stuck inflator valves and accidental button operation / confusion.

28% of people never get their BCDs professionally maintained, and a further 18% only do when a problem happens. I have to admit to being in that 28% who have never had their BC professionally maintained, although I have cleaned up the inflator valve whenever I’ve had trouble with it. I have problems with a stuck inflator valve on a Halcyon Eclipse wing almost every year. Mine is the old metal inflator which Halcyon did seem to have trouble with and don’t use any more. What tends to happen is that it sticks slightly open, but not enough to be obvious. Gradually I find my buoyancy is off and I have to dump some air to maintain it. Eventually it dawns on me that I’m having to dump air while my depth isn’t changing, at which point I realise what’s happening and disconnect it. Then I have to take it apart and clean it up. On a Philippine dive trip soaking the bits overnight in vinegar seemed to do the trick.  I really should change it to the newer plastic one, but I quite like the response of the metal one – the plastic one doesn’t feel quite the same somehow.

More recall news, this time from Cressi, who are recalling Cressi Ellipse Black MC5 regulators distributed between March and August 2009. The problem is related to the high pressure port being partially blocked which can lead to an inaccurate reading on the pressure gauge. this from their website:

The words “Cressi Black” appear on the cover of the regulator’s second stage, and the words “Cressi MC5” are visible on the regulator’s first stage. (See photo above.) Retail price ranges between $280 and $309.

Hazard: Partial obstruction of the High Pressure port can produce an inaccurate reading on the pressure gauge, resulting in a slow descent of the needle in the pressure gauge. The inaccurate reading on the gauge poses a drowning hazard to divers.

Remedy: For a free repair, consumers can return the Cressi Ellipse Black MC5 Regulator to any Cressi-authorized dive shop or directly to Cressi- sub USA at One Charles Street, Westwood, NJ 07675.

For more information, call Cressi-sub USA at:
(800) 338-9143
between 9:00 a.m. and 5:00 p.m. ET, Monday through Friday, or visit the website www.cressi.com

For more information, please visit their website.

After Halcyon’s problems with Over Pressure Valves last year, this time it’s the turn of Dive Rite.  The following quotation is taken from their website:

The Over Pressurization Valve (OPV) springs found on Dive Rite wings manufactured between June 2006 and October 2008 may rust and fail allowing the buoyancy compensator devices to leak. The wings may be red, blue or black in color and have serial numbers falling between 42000 and 72000. The following models are affected by this recall: Travel, Venture, Rec, Trek, Classic, Nomad and Super Wings It does not affect EXP or 360-branded wings. The recall does not affect lift bags, surface marker tubes or other Dive Rite inflatable devices.

Due to the serious implications of an OPV spring failure, consumers should stop using the recalled diving equipment and have the OPV spring immediately replaced by a Dive Rite authorized dealer or distributor.

We apologize for any inconvenience and encourage Dive Rite wing customers to contact your local Dive Rite dealer or Dive Rite directly at 800-495-1046 with any questions.

You can find out more, including instructions on how to replace the spring,  from Dive Rite’s website.

Halcyon is recalling certain Eclipse, Evolve, Explorer, Pioneer and CCR35 buoyancy compensator’s (BCDs) manufactured between January, 2006 and September, 2008. In addition, selected Halcyon inflatable devices (Lift Bags, SMBs, DAMs, Surf Shuttles and Diver Lift rafts) may also be affected.

The stainless steel Over Pressure Valve (OPV) spring could become excessively corroded, causing it to fail and the valve to leak. Halcyon have claimed that the defect is limited to a very small percentage of springs used between Jan 2006 and Sep 2008.

According to Halcyon’s website – “Worldwide Halcyon distributors will be initiating a similar inspection and replacement process through their dealer networks. Halcyon Manufacturing, Inc in High Springs Florida will also inspect those BCDs or Inflatables sent directly to our facility, replace the OPV spring if necessary and provide free return shipping to the customer.”

Here are some examples of good springs:

Whereas here’s a bad spring:

You can read more from Halcyon’s website.

My Eclipse is too old to be affected. But instead I’ve got one of those stainless steel inflator valves that insists on sticking open from time to time, which I have to clean up every year.

This from Mares:

Please be informed that we have discovered a quality issue on the O-ring assembled on the Nemo Air Quick Connector.

Under certain circumstances the O-ring can fail and consequently Nemo Air may start leaking through the Quick Connector. As a result, there is a continuous, albeit slow, loss of breathing gas. This situation could potentially lead to an accident, hence Mares has decided to issue a product recall. The solution already exists in the form of an O-ring of different material and hardness which can be retrofitted onto the Quick Connector of your current Nemo Air.

You can find out more from the Mares Home Page, where you can download a PDF with the full safety notice.

Scuba STAR Network are conducting one of their regular safety surveys, this time on BCD safety. You can help by going to their website.  You can also see results from their recent survey on regulators.

Suunto have discovered a software bug in their D9 and D6 computers. On rare occasions the bug can cause the instruments to incorrectly track dive time. The following serial numbers are affected:

• D9 – 62102582 and below
• D6 – 62103693 and below

They strongly recommend that if you have one of these units, you don’t dive it until the software has been upgraded. The good news is that as a complimentary service, at the same time they upgrade your software, Suunto will apparently replace the battery and perform a pressure test free of charge.

You can find out more detail here.

Recently our dive club has had a question mark about one of the junks we use. Apparently the boatman is not being “very helpful”. Personally I’m very surprised as I’ve always found him extremely helpful, he keeps a good eye out for divers knows where they are, and he always helps loading and unloading tanks. Over the last few years he has also made a lot of effort turning his junk into a suitable diving platform. I think people might be forgetting that when we started using him he knew nothing about divers or diving and I would hate to see us having to go through that same learning curve with someone else.

Anyway thanks to the BBC we may have a solution. In Wisonsin someone who obviously has too much time on his hands has carved a giant pumpkin into a canoe! He’s now planning to paddle it 150 miles in 8 days to raise money for children with special needs. Good luck to him. I’ve never been a big pumpkin fan, so the prospect of spending 8 days in one really doesn’t appeal to me!

You can see the video here.

Not a particularly new story, but thanks to Alex G. for pointing it out to me. Kirill Larin, an assistant professor at the University of Houston in Texas, is attempting to produce a device that could routinely be used on people moving from a high pressure to a low pressure environment, to try and identify the onset of decompression sickness (DCS). His research is in optical coherence tomography (OCT), which uses lasers to make high resolution images of biological tissues.

For any non-divers who have stumbled across this article and haven’t immediately abandoned it for something more interesting, DCS happens when gas such as nitrogen which has been dissolved in body tissues is released and forms bubbles. From a diving perspective, as you descend, the pressure increases which forces more gas to dissolve in the various tissues in your body. As you ascend the surrounding pressure reduces and the gas is released but it tends to group together into microbubbles. Ideally these are expelled through the normal breathing process, but if the pressure reduction happens too quickly then larger bubbles can form which can start to cause problems such as joint pain, neurological problems, skin rashes, burning chest pain. Ultrasound has been used to study these microbubbles, but has a resolution of 80-100 microns, whereas OCT promises images with a resolution of only 2-10 microns, which will detect much smaller microbubbles in the bloodstream and could help diagnose DCS early enough that it can be treated before becoming symptomatic.

The reasearchers’ goal is to produce a portable device that can detect problems in seconds just by shining a light on a person’s skin.

There is an article Popular Mechanics’s website, which mentions possible beneficiaries as divers, but also astronauts and high altitude pilots once they land. Although a pilot landing would face increasing pressure as they descend, not decreasing pressure, so should not be susceptible to DCS unless they’re are other factors involved such as a space capsule or a plane or a flight suit being pressurised to more than 1 bar.

Anyway it will be interesting to see if it is possible to produce a device that is easy to use, portable and cheap enough to start appearing on dive boats. I’m not holding my breath – but then as a diver we’re always taught not to hold our breath!