Well, I'm working nights here on HAWSEPIPER's Afloat Global HQ/ Center for Involuntary Abstinence. Has anything new been going on in the world?
Crazy days.
I was unhappy that while I was at home the first week, we had a completely scratch crew aboard- I did a good handover, taking the time to walk through with the ride over crew, go over the books and my copious notes on what they needed to know.
I mean, nobody drives the car like the owner, of course some things aren't going to go smoothly, and I assume there'd be a learning curve and some sequelae I'd deal with on coming back to work, but we're professionals, sorta, and the senior of the fill-in guys is no spring chicken, and jumps around a lot working over on his time off. Guy would know a few things about a few things, and did. But not everything, and of course he's got no vessel-specific experience, which is a very valuable thing. No matter, he arrived behind the 8 ball at some level, which is what happens on your first time on a new vessel. You do your best and your past experience gets you through. I knew the guy wasn't going to sink my HQ. Still, one of my biggest concerns was that no matter how experienced a tankerman is, many guys lack the experience and patience to properly 'run in' a new deepwell cargo pump, at least to what my standard (and that of the guys who taught me) is.
So we have 3 different cargo pumps on the HQ, segregated within 3 separate piping systems so that we can carry 3 different grades of noncompatible fuel at the same time without the need to flush and wash the tanks and piping when we change products. specific tanks on board ONLY carry specific types of fuel.
For our cargo pumps, essentially we have large diesel engines mounted on a platform, with a transmission and reduction gear bolted to it, that is connected by a 6' stub shaft to a right-angle drive, which is bolted to the top of a pump shaft that runs deep in the tanks.
I'm not showing you pictures of my setup, because I didn't ask my employer if I could. It's a respect thing, even though they'd probably be cool with it.
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| Similar to this, just much bigger. |
The pump shaft is a steel cylinder that runs from deck level to the bottom of the cargo tank piping. The piping sits about 2 1/2 feet above the bottom of the tanks and runs through all the tanks with t-connections to sumps in the individual tanks- We have two pipelines that run fore and aft down the whole hull, and each branches to each tank, and one set of tanks midships that have their own pump sitting on deck above them. At the base of the pump shaft is a 3-stage impeller that forces oil upwards, where it hits the top of the pump shaft and exits into the above-deck pipelines.
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| close enough. This actually shows a mechanically-sealed pump, whereas I have a stuffing-box seal, seen below. |
The shaft seal at the top of the pump shaft is a packing gland, AKA a stuffing box. I work with diesel and heavy fuel oil, which thankfully have not-so-explosive vapors compared to gasoline or naptha or other nastiness. Those fuels use mechanical shaft seals with similar pump setups. very different animal.
The packing is fine-woven teflon-impregnated synthetic material (used to be greased cotton), cut into ring shapes, and compressed by a bronze collar down to the bottom of the stuffing box by bolts. The tighter you compress the packing down, the more it expands outward. This generates heat by friction. Now, working with oil, heat is bad when there is a lot of it, of course. My big concern is that not all tankermen have experience in running-in or repacking worn out packing in a stuffing box. Many just call and ask for an engineer to take care of it. On the HQ we only get an engineer on-scene if we make a phone call, and being handy guys, can do many tasks ourselves (which used to be required), and like many old-school tankermen, we've all fucked around with stuffing boxes much much more than we'd like... but we weren't there. The riding-over guys were there.
Now, 'running in' a stuffing box isn't rocket science. When the pump is first used (and not run dry, actually pumping fluid), at low pressure you have the collar that pushes down the packing set fairly loose, and wait for the fluid to work it's way up through the packing material as pressure rises inside the pump. when it starts dripping (if it starts dripping. It might not until the pressure gets higher), you tighten down on the bolts that force the collar deeper to slow the seep, 1/8 or 1/4 turn at a time on the nuts. When the seep slows, you sit back and wait. After a few minutes, as friction builds, the packing material now has oil soaking in it too, and the oil is getting hot, along with the teflon-impregnated fibers and the heat will transfer to the stuffing box and shaft too. After a few minutes it will start to smoke a bit, at which point you shut down the pump, and let it cool for 20 or so minutes.
Now, you want the collar that compresses the packing to be made of bronze, because it's more ductile and wears easier than steel. Going back and forth tightening and loosening the nuts that force the collar down isn't' a precise process and the collar is fitted closely to the drive shaft. It WILL rub against the shaft at some point, and being made of bronze, the bronze will heat up and start to wear away a bit (and there being oil seeping out, will smoke too. It will melt if you let the heat build, but in my experience it's not unusual to see some fine powdered bronze around the collar after it's worn in.
The takeaway here is that the heat has to be managed, and it's necessary. I WANT to see the heat build, as everything wears in. I'm hanging out with an infrared thermometer or a Mark 1 Index Finger, and when it gets hot and smokes or just starts feeling hot hot, the pump is stopped and it's time to let it cool.
When the pump is stopped, the oil in the shaft falls down to the same height as the oil in the cargo tanks, and the heat dissapates rapidly, as the heat was limited to a very small area. Before the heat dissapates, though, the friction actually bakes the shaft packing material, hardening it at its' surfaces, and making it less permeable. After the whole works cools to the point that it's merely warm to the touch, the pump can be restarted, and the oil will usually seep at a much lower rate or not at all... if it still seeps at a high rate, the nuts on the collar can be tightened down a bit more, and then if all is well, I watch the heat again. Ideally, the heat will not rise to anywhere near what it did the first time. If it does, the pump must be shut down again and the box allowed to cool, rinse and repeat until satisfied.
Now, that was a lot of typing to describe, badly, a VERY simple process...which the fill-in-guys emphatically didn't do. They didn't blow up my barge, thankfully, the system is more retard-proof than that, but the fill-in guys sure made a mess, which they should have known how to avoid. Without airing laindry publicly, knowing what I know about the people involved, I guess I shouldn't be surprised... but in a stroke of good luck, my partner B arrived a week before I came back to work, and found that the engineers had been called to unfuck things and the fill-in guys tidied up halfassedly at least... and B is a guy who abhors disorder. I arrived to find everything suspiciously as good as new, which is odd in a not-so-clean process, and got the 411, and all is well without my having had to do squat. Which I like very much.
Anyhow, that took way longer to write about than the download I got from B over what happened.
"What happened here?"
"That shithead _________ guy fucked up and killed the packing on the port pump.. He had the engineers unfuck it 'n repacked 'afore I got here."
"Well I told the guy the pump ain't been run-in yet, before I went home. How bad was it?"
"Bad enough."
"Damn."
"Damn."
We're coming up on 15 years of working together, B and I. We don't have to talk much to understand each other on multiple levels. Benefits of working with a good guy for a long time.
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