Sunday, April 12, 2015

Mr. fix it

I pride myself on being pretty handy around the house.
Watching my dad (a former ships' electrician) mess with wiring, and my brother with carpentry, auto repair and pretty much every other form of home ec for men, I've got a good handle on being able to handle a lot of tasks on my own around the ol' casa.

But shit like this past weekend make me awful happy that I'm not a marine engineer.

 You see, our deck crane shit the bed the other day.

     Another cargo load, at one of our regular stops, and I'm at the base of the crane, swinging our 100' heavy fuel oil hose over the side, and as I'm swinging the hose over, there's a big boom that leaves my ears ringing, then a smaller boom, and then the crane stops.

      The swing motor assembly is no longer working. Well, the swing motor, a compact hydraulic motor, is working fine, it's just that nothing is happening. Turns out the gearbox for the swing motor is Pining For The Fjords.

   The gearbox is the size of a shoebox, weighs about 150lbs or so, and is bolted to the turntable on the crane.

 We end up finishing the load, get the hoses back aboard (more on that later), sail, and spend the night lying to at my company's HQ dock, to await repair before the scheduled discharge.

        Between rolling in chop and swinging heavy, awkward, sometimes very unbalanced loads at high angles for years, turns out the main gear that runs between the gearbox and the turntable gear (the base of the crane IS a giant gear) sheared right off- a very stubby 2-inch thick solid steel cylinder, sheared right off. That's a LOT of force to be able to do that.

 Anyhow, getting the damn gearbox switched out was an exercise in awkwardness involving a smaller crane, chainfalls, and working at close quarters with another man. Very awkward business, trying to get a 150lb shoebox out of a space that's 4 feet in the air, or just tall enough where you're working to lift something at waist height, and bring it up to eye height while reaching inside a space inside a cylinder with steel obstructions everywhere, and all of it just tall enough to make it impossible to lift with anything but your forearms and lower back, with the only handholds being just large enough to use two fingertips for leverage.

     I don't know how our engineers and shoreside mechanics do it day in and out. By the time we got everything buttoned up and working again, I was feeling pretty grumpy and had grease in my hair and down my shirt.

 There were some pretty scary/funny moments, though. Getting those hoses back aboard at the end of the load was an all-hands effort, and even the dockmen helped. Without the swing gear in place, the crane swung in the breeze, and, when I first asked the dockman to let go the hook that was dangling on the cable, holding the hoses, the crane took off like a rocket- there wasn't anything holding it in place anymore, and it wanted to feather into the wind, which was quite strong. Well, with a 60-foot arm, plus another 40-feet of cable out, we basically had a 100-foot diameter propeller with a 120-lb wrecking ball (the hook) at the end. Unable to control the swing, and in fear of wiping out pipes and light towers on the dock, I did the only thing I could think of to make the swing circle smaller: I raised the boom.

      Well, centrifugal force being a thing, when you decrease the swing radius of a turning object, you increase the angular momentum, so the higher up the crane went, the smaller the swing radius, and the more force applied, so it looked pretty dramatic, the crane swinging in circles until I could get the boom up and the cable reeled in.

 Getting the hoses back aboard was a simple matter of recreating the old boom-and-stay rig, and using the #2 cable as a power block, to heave the crane around. We were going to attach the #2 hook to different objects and use it to haul the boom around, but it turns out that with a couple of warm bodies available, we could just muscle it into rough place, lift the hoses vertical, one at a time, then everyone on the #2 hook dragged the whole crane assembly around and the hoses came back aboard. I grease the ever-loving shit out of that crane, so the bearings are smooth.
 Anyhow, Flintstones power carried the day.

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