Replies to This Discussion

Permalink Reply by JOEY C. SEGOVIA on July 30, 2010 at 12:39pm

Craig great communication on this and I for one appreciate you looking out for your divers doing the work and trying to put yourself in their "hats" so to speak.
As most will attest in this business this tends to be an exception and not always the rule. But I will say that when you have real on site collaboration and support from the people you are working for it makes a world of difference in every aspect from safety to on time completion. All of that being said I'm also not real clear on the "rectifier" like you I believe "current" is "current". That being said I personally do not believe that "current" as it relates to morbidity and mortality in underwater burning is necessarily the
"issue". By this I mean that in theory and in practice you can "burn" with the current "off". The current is used to "light" the burning rod and the O2 gas sustains the ignition of the magnesium tipped rods which burn at a very high temperature to burn/melt the object being "burned". Forgive me if I have reiterated to you what you may already know however; I have been burning for over two decades and other than the "normal shock" that we all feel I have never been nor seen anyone injured by the "current" or "current source"
itself. The gases and or the combination of gases produced during the burning process specifically the unknown build up of these gases is a major cause of concern and as we all know can be fatal. There may not be a real cure all for the potential hazards of underwater burning but "awareness" of the conditions
at the burning site,"front end" design on a project including a true hazard analysis that can minimize them, real training and qulaification of the diver to a certain skill level all are steps in the right direction. Encourage your diver/burners to truly be aware of the surroundings and to burn as efficiently as possible I always remind myself to get "comfortable, think and learn as you burn" which means to take notice of what is happening with each rod and whether the burn is venting or not , etc. I hope these words will help. Safe diving to all.

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Permalink Reply by John Carl Roat on July 30, 2010 at 12:59pm

If in fact as many of us have felt a slight tingling when the knife switch is open using position when using a Rectifier. That means to me there is electricity present. In other words the current should not be in the cables. Well think about, all that dead space in the handles of the burning torch.

You don't pick up the torch when the diver is not using it, lets say they are turning around the bell. So for a couple hours the torch is just hanging there. Now if in fact there is current leaking down the ground cable you have small amounts of Hydrogen building up

Both the ADCI and IMCA have known there are problems for years. Testing I ask for over 5 years ago. They have done nothing, I believe that we can do this safe, but we don't even know which rod makes the most hydrogen per inches cut.

http://www.offshorediver.com/content/index.php?option=com_content&a...

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Permalink Reply by JOEY C. SEGOVIA on July 30, 2010 at 4:12pm

Well said and points well taken John. There is no doubt the diver knows when there is current he is the first one to know! I'm with you that there needs to be some real world testing on all of this and I do not mean testing to support the manufacturers corporate position but rather analyzing and interpreting the data to truly help the ones doing the burning: Divers. I know you have been asking for this for a long time and I fully support you in this endeavour. I too believe that burning can be made safer the so called associations need to get on board with the rest of us.

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Permalink Reply by Craig Smith on July 30, 2010 at 4:21pm

Hi John and Joey.

OK. I am on a steep learning curve.
Usually the divers maintain the Broco gear and all I have to do is hook it up. I have just checked out our gear on board and it is a Lincoln DC welder, so in other words a rectifier. As per the Broco instructions, the + terminal is earthed and the - terminal goes through the "knife switch" (actually a contactor. Very few knife switches used on the sat systems I have worked on).

I think what John is getting at is that there may be some voltage present between the earth clamp, which is positive DC, and the earth of the ship which is earth AC. This would account for the tingle that he is feeling. To find out why this is happening, I would have to look closely at the welder rectifier circuit. It really should not happen as the DC circuit should be isolated from the AC circuit. In a generator, this is certainly the case, as it is in no way connected to the ship's AC supply.
One simple way to ensure complete isolation would be to run 2 contactors, or just use a 2 phase contactor and 2 poles. One contactor/pole is for the earth lead, and one for the torch. This would ensure 100% isolation when the torch is made "cold". Extra cost is minimal.....
With knife switches, you would need 2 x Knife switches, but they don't have to be opened together, as it's only a long term safety device to stop any potential ignition when the torch is "cold".

What do you think??

Craig Smith, REM Poseidon, Saudi.

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Permalink Reply by JOEY C. SEGOVIA on August 1, 2010 at 7:24am

Dale,
Your points are very well stated and very well taken. I for one appreciate your passion and as a fellow experienced hand in this business I feel the frustration and yet I believe in a real commitment to it.
Anyone who goes into this business/profession thinking about the "money" will be sorely disappointed. I, as you have been, have been in circ**stances at a jobsite where no amount of money in the world could actually "compensate" you for what you were having to do at that moment: working in a h*** or hatch or monitoring a jet sled several hundred feet or not in zerovisibility and swift currents etc. has to actually "mean" more than"money". To me it has always been more about believing in what you are doing this is real commitment. My hope is that this topic can unify us to become a stronger voice as a true professional organization with a voice just like the engineers,airline pilots
and diving contractors do and I do not mean a "union" in the traditional sense. This voice of ours will have to bring on board some type of Govt. agency inorder to be "heard". I for one will make a motion that we form our own professional organization whose intent would be to promote real standards across the board and increase professionalism in all aspects of commercial diving as divers. I do not believe that this should be an organization that has an "us versus them" mentality. I have always said that divers will never be treated as professionals until they start acting like professionals. It may not be easy but nothing in our line of work ever is. I for one will commit to this and if every diver or tender who has ever complained about coming together would support this then it will happen. Fair winds and following seas to you and yours.

Permalink Reply by Tom Ryan on July 31, 2010 at 1:10am

Craig,
We use a 2 pole 'control switch' It comes in a small pelicase and is manufactured by Pyranha in the UK. We get them in the UAE through Divex. website is http://www.specialwelds.com/products/piranha/index.htm.
Off the top of my head I think they cost about 1800dHs or 350GBP.
Regards
Tom

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Permalink Reply by Craig Smith on July 31, 2010 at 12:39pm

Thanks Tom. That should stop any stray currents, rectifier or no rectifier. Very simple and no more problems. I will suggest that they fit that on here as well. Thanks for your help.

Cheers, Craig.

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Permalink Reply by John Carl Roat on July 31, 2010 at 2:00pm

If the divers a using any torch with dead space between the handles, suggest they close off a rod as I did in the pdf and snoop past the trigger. Also if it is the Broco 22 make usre the cable set screw is tight.

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Permalink Reply by JOEY C. SEGOVIA on August 1, 2010 at 6:38am

John,
Roger that and thank you for your advice on the snoop and the set screw.

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Permalink Reply by JOEY C. SEGOVIA on August 4, 2010 at 7:31am

Roger that Dale. I do believe it is possible for the grounds to absorb stray current
and I also think a knife switch on the ground certainly would not hurt the situation but there could be a "learning curve" as to when it is open or closed especially with a deck full of tenders and equipment running. Very good to recognize that topside can be vulnerable as well to any u/w welding. Keep it up.
Safe diving to all!

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Permalink Reply by JOEY C. SEGOVIA on August 1, 2010 at 6:36am

Tom/Craig,
Tom thank you for letting Craig in on the two pole contacts hope it helps. Craig I think that it is worth mentioning that somewhere in all of this there exists the natural and somewhat unavoidable "water grounding" of the vessel and the structure being worked on especially in salt water. In my experience there is always a little bit of stray current somewhere. Safe work to all on your projects.

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Permalink Reply by JOEY C. SEGOVIA on August 4, 2010 at 7:37am

Roger that my man! Yes I do need to think seriously about Leroy's offer. However, in the mean time if you need it jump on it. I'm sure we could set some other piling somewhwere at his dock to support another boat as well. I have some lift straps and lift motors that are used but in good shape if you are interested. Let me know. Also,any word on status of offshore work?

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