By Scott Adams
I was hired out of college at Mare Island Naval Shipyard, which overhauled some of our nuclear submarines. They assigned me to the Hydraulic Testing section. I had only been working for a couple of years when I was given a problem to solve. The Captain of one of the submarines was complaining that the pneumatic capstan no longer worked right (we also were the pneumatics and masts and periscopes section). It only turned at a low speed instead of the correct speed. He said it worked fine when the overhaul was started and that they couldn’t figure it out and wanted to know what we did to it.
That was puzzling, as we had not been tasked to work on the capstan for that boat. I went out to investigate it, and saw that what looked like the exhaust ports on the air motor had stripped threads, but there was no reason for it to have been used. This particular capstan was stored inboard during diving and brought out and hooked up for docking, which meant that the inlet port was connected and disconnected every time they were in port.
I went back to the office and looked up the motor diagram. Even though it looked like the motor should be symmetrical (i.e. you could plug the air line into either port and have it work), it actually wasn’t. If you hooked the air up to the exhaust port, it should only run at half speed in the opposite direction. Capstans don’t care which direction you turn them. You just wrap the cable the other way. I took this to the Captain and told him that someone had stripped out the inlet port threads and decided to put the air line to the exhaust port instead of fixing it correctly. I told him that if he had the inlet port re-tapped and moved the air line back to it, the problem would be solved. The Captain asked me if I would bet my career on it, and being a young brash engineer, I told him that I would. And it turned out that I was right. I worked there for several more years before leaving to go into the oil industry.
It always reminds me that you just can’t look at the externals of something to figure it out and a little investigation can make you look good.
Scott Adams, senior staff engineer/project manager, Shell Pipeline Company LP graduated in 1984 with a BSME from University of Idaho. He worked for just under five years at Mare Island Naval Shipyard as an engineer. Then he worked at Chevron Pipeline Company as a seconded Bechtel engineer before being hired directly by a company that is now Shell Pipeline Company LP. He has worked there as an engineer for 20 years designing, upgrading, and constructing pipelines and related facilities.