I went to diving school in 1974, and worked for about a total of eight years after that. I am commenting on methods and equipment used at that time. In the ensuing years, I'm sure there's been changes and better stuff. Ernie would know about that. So, my comments are just on the way we did things back then, and with the new stuff, someone who has used it recently should comment. Autodark for even above water welding wasn't even a figment of someone's imagination at that time.
For all other things I say that are wrong, please consider that they are just in error, and not really wrong.
"SteveB" wrote: Control is totally topside with a knife switch. Diver sez make it hot,
^^^^^^^^^^^^^^^^^^^^^^^^ I can think of two reasons for using a knife switch: 1.) It is possible to see at a glance whether it is on or off. 2.) The switch carries the full welding current.
You are in constant audio contact with your knife-switch operator topside. When you are ready to weld, (assuming you are at the Blue station) you say "blue diver, make it hot" The communications person repeats that statement "blue diver, make it hot" The knife switch operator closes the switch and replies "blue diver hot" Communications relays the info to the diver "blue diver hot.
When you are done with your rod, you go through it again with "blue diver, make it cold" and so on.
You never change a welding or burning rod with the knife switch closed or you get zapped.
If you are caught trying to do it on the job, you will be fired.
Employers don't appreciate you endangering their insurance policies. If one diver screws around and gets hurt, you can lose your insurance and hence your contract for that work.
Commercial diving has changed little in the last 30 years. The only real change has been greater and greater enforcement of safety procedures, and equipment maintenance.
Also the hats have gotten better as far as regulator designs.
Divers don't like new stuff if the old stuff works.
There is less and less underwater wet welding due to insurance costs. They have developed new dry habitat welding procedures for pipeline repairs.
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It isn't like the insurance companies actually "like" divers. They just don't like paying their widows large cash settlements.
"Ernie Leimkuhler" wrote: You are in constant audio contact with your knife-switch operator
^^^^^^^^^^^^^^^^^^^^^^^^^ In my earlier post, I asked, "Why a knife switch?" Every time one of you talk about turning the welding power on or off, you specifically say "knife switch." Not contactor, or breaker or just "switch." So I wondered whether it is because it is because it has to carry the full welding current, and because you can tell by looking at it whether it is on or off.
My take is that the welding machine may be remote from the dive station, so one wants to have the on/off control close at hand to the man who's talking to the diver. Not to mention having the noise of the welder farther away. And the fumes. And you are right on the two counts in MHO. The switch is heavy metal, and one can tell by looking if it is open or closed.
"Ernie Leimkuhler" wrote in message news:151120092015035421% snipped-for-privacy@stagesmith.com...
Looks like what we called a SPAR, or subsea pipeline alignment rig, seriously heavy, seriously difficult to get into position, seriously difficult to cut and align a repair pup, and seriously crowded, with an argon atmosphere where men had to be masked to weld inside. Didn't work very well.
Sounds like stuff hasn't changed a lot except the hats. I see a lot of new Kirby stuff that was just on the cusp of evolution in 1980. Most were Kirby-Morgan band masks, and few had neck rings, except some of the old Descos and Savoies. There was a black one that looks like the current Kirby, but I do not recall its name. Head protection was something you strapped on OVER your band mask.
For us, safety practices and equipment maintenance were just a cadre thing. OSHA rules do not apply in international waters, and we would repetitive dive out of N, O, and Z groups. We were pirates and kings of the world, and had our own group. We always did have a chamber, and "hits" were common. Equipment maintenance and all diving equipment hookup, take down, and operation was left to the dive crew, and not allowed by any other group.
Got on a union job one time for Bannister Pipelines, the Alaska pipeline people. They found out that they could put a couple of more mechanics to work, so insisted that we use union mechanics to service our dive compressors, even start and stop them. That cost several VERY expensive delays, waiting hours for a mechanic to be airboated or choppered across the swamp to start up a compressor for a ten minute dive. That lasted about two weeks until one of them put regular oil in an air compressor, and sent a guy to the hospital with lipid pneumonia. After that, we were given special dispensation from the union to handle our own stuff. The two mechanics did stay on for the duration of the job, though, "just in case." About two weeks after that, I saved a laborer from drowning, and we raised another notch in the pecking order with all the union hands. Before that, they had used union laborers to swim lines under pipelines, and do in water work until they had a couple of close encounters with alligators, and the laborers refused to get in the water any more. People were leech magnets without a wet suit. At first they were standoffish as we weren't union, but got Davis-Bacon wages. Then when they didn't have to get wet or dive with the leeches or alligators, they didn't mind so much. Then when I saved "Jivin' Joe", a black laborer from Opelousas, we were tight. That was 90 miles of 54" OD concrete coated pipe through the Atchafalaya Swamp from Centerville to Belle Chasse, LA. Quite a job.
All automated FCAW shielded bug welding except for tie ins. 50% cutout rate.
Steve
Gulf of Mexico work was terribly hazardous, not so much from the dive crew, but the other crews we worked with and around. And weather. I look back at it now and ask what I was thinking. It was high adventure, though.
Steve, who misses the good old days, but not that much.
I think there's another reason, too. They're using large DC currents, which contact type breakers don't always do a good job of interrupting, since there's a lot of arcing (no 0v at 120 times a second like ac, which helps extinguish arcs). A knife switch gets you a nice big conductor separation distance in a hurry... --Glenn Lyford
This has been a very educational thread and I have followed it with avid interest. Not that I would actually try the procedures described, I am a bit old for that sort of work, but I always wondered how that type of welding was accomplished. My thanks to Ernie, SteveB and all the other contributors for all the information that was provided.
When we were in school, they told us that welding underwater would accomplish up to 80% strength, and 50% ductility because of the quenching action of the water. They told us that they would show us how to do it, but that it was not generally used in the field because it was not nearly as good as a dry weld. In eight years, I saw underwater welding done ONCE, and that was some hardfacing rods burned on to a rig leg where another was being put on outside with a clamp. The hardface was supposed to improve conductivity so as to avoid faster corrosion of the new element. On top, the welders laid the hardfacing rod on to the new clamp in the areas where it would contact the existing leg. Underwater, we had to use a 30,000 psi water blaster to clean off where the clamp was to go. Only the best were sent down to do those dives. Right after the hardfacing, the brace was clamped on, forever obscuring investigation or inspection. A couple of years later, one of the divers, at a party, and loosened by a few Crown Royals and Cokes said, "God, I hope no one actually looked at those welds. They were horrible. It is a good thing that jacket legs are pumped full of concrete because we blew a lot of holes."
IMHO, and only from my own experience in what I saw in the field, no really important welding is done underwater unless it can be cofferdammed and done in a dry environment. There was, however, a LOT of electric oxygen cutting. Everything else was either welded before it was sent down, brought up and welded and then sent back down, or made in a clamp configuration so that no welding was required.
It was after those years that I got heavy into welding, and understood that water and welding don't go together well at all. Just look at what a little dew or condensation or water absorbed by rods will do to a weld. Now, magnify that by 100, and you come to the starting point of welding underwater. Most of what you see on TV is actually cutting, not welding. Sure, there is a little welding, but not much, and of that, nothing critical because it just doesn't hold.
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