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Bridge Ringing for Half-ahead, Give 'Em Half-ahead

written by: Willie Scott • edited by: Lamar Stonecypher • updated: 6/2/2011

I was sailing third engineer on an Ulster Steamship cargo ship in 1969. We were on the UK to Montreal, Quebec and Great Lakes run, which was great in the summer months, but the winter weather could turn nasty giving a rough old passage across the North Atlantic, especially with a twisted prop blade!

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    Many years ago when I was a young engineer at sea, I sailed on a cargo ship as third engineer. This ship was about 6000T and had a two-stroke Sulzer marine diesel engine. We were trading between the UK, Canada, and America via the St. Lawrence Seaway and the locks.

    The incident occurred when we were coming alongside at Toronto. I was in the engine room at the controls and had just answered the engineroom telegraph, which was ringing for half-ahead.

    This article is about what happened next, and what I learned from the incident. We begin with a quick overview of the controls, and how we operated the engine room telegraph to the bridge requests.

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    Overview of Operation of Marine Diesel Engine Controls

    Most ship main diesel engine controls work on the same principle.

    There is a control station, usually located on the front aft side of the engine.

    • Engine Main Controls

    There are two main control rods, one operating the air start and the other the fuel. I used to watch the flywheel when starting the engine and as soon as sufficient RPM was built up on air, I would operate the fuel rod, and cut back on the air. Too much air and you would use up the air in the reservoirs too quickly; too much fuel and you would lift the cylinder head relief valves. It was a matter of practice, and we got plenty as we stood six hours on – six hours off watches, whilst transiting the locks between the Great Lakes.

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    How the Engine Room Telegraph Works

    This is situated right in front of the engineer on the controls and is used when on standby and maneuvering to communicate what speed and direction the bridge required from our engine. The telegraph on the bridge is identical to the engine room telegraph and had numerous sections which were illuminated along with very loud ringing when operated. We answered this by moving a reply handle on the engine room telegraph.

    The sections were stop, dead-slow ahead, slow ahead, half ahead, and full ahead with the same for astern movements.

    We knew what RPM each movement represented, so as soon as the telegraph rang, we answered it with a reply handle, and then gave the required engine movement. Both engine room and bridge officers kept a strict record of the time and movement requested throughout the period on standby.

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    The Incident

    It was on one such occasion that I was on the controls, and had just stopped the engine, awaiting the next bridge request. The telegraph rang to ‘half ahead’ and I was about to answer this when the Chief Engineer came hurtling down the engineroom steps, colliding with the electrician who was taking down the telegraph movements.

    The telegraph rang again, this time to full ahead. I still hadn’t started the engine as the Chief was shouting something into my ear. Now, this Chief was great at his job, but he had a very bad stutter. I still couldn’t make out what he was saying, and the electrician was pointing at the telegraph and his watch, signifying that the bridge were getting a bit agitated as I still hadn’t answered the telegraph or started the engine.

    Bugger this – I answered the telegraph and gave the engine a good blast of air then onto fuel, lifting a couple of safety valves in the process, as she was very sluggish to turn over.

    The Chief came beside me and pulled the controls to stop, then put the telegraph to stop and went onto the bridge phone. The rest of us were still bewildered by all this. I had never seen anything like it before, or since, for that matter.

    Eventually the chief came off the phone and between breathlessness and stuttering told me that the stern of the ship was right on the concrete jetty, the propeller very close to it as well. What he was trying to tell me was: "Don’t start the engine, Willie!" But of course I had no idea what he was saying and started the engine. The sluggishness was due to the prop touching the concrete jetty supports.

    When we eventually were tied up, I went aft with the Chief and Second Engineer. Leaning over the stern rail we could just get a glimpse of the propeller as it rotated on the turning gear, and saw the damage.

    I was ready for a good lamblasting from the Chief, but he blamed the pilot and the Captain for being too close to the jetty.

    We got the Lloyds surveyor down and pumped ballast for’d, lifting the prop clear of the water, then went around aft in the "jolly boat" for an inspection. We had lost half a propeller blade, twisting another out of line a little.

    We adjourned to the Chief’s cabin and over a few beers convinced the Lloyd’s man that we could run the engine at reduced revs. He asked us to try the engine out tied up to the wharf, so we fired up the engine and ran her at half speed ahead and astern, while checking the prop shaft bearings, thrust block and stern gland for vibration or overheating.

    Eventually the Lloyds surveyor was happy and told us we could sail for home at reduced revolutions. This was very good news for us as we could easily have been stuck in Toronto for the winter if we had needed a new prop, as we didn’t have a spare one. Or we could have had to wait for repairs to the damaged one.

    We sailed the next day and after negotiating the Welland Canal, headed down the St Lawrence Seaway and out into the Atlantic Ocean.

    Now this can be very rough crossing, especially in the winter months and this was the 10th December. It normally took us ten days to get to Belfast, but at the reduced revs and the heavy weather, we were going to be lucky to be home by Christmas.

    We kept a very strict watch on the thrust block temperatures, and had a junior engineer and a greaser stationed full time down the propeller shaft tunnel, looking out for raised temperatures and vibration. I had recommended we slackened back the stern gland studs until there was a good steady flow of water. The stern gland and stern tube were going to bear the brunt of the prop vibrations, so the seawater flushing through would keep them cool.

    We made it into Belfast without further incident in time for Christmas, and I went on leave whilst the ship was unloaded. The shipyard engineers brazed a new tip onto the broken blade and realigned the twisted one.

    I rejoined the ship a few days after Christmas and we sailed for Liverpool, giving the engine full revs and thoroughly testing the repaired prop. Everything went well and we arrived in Liverpool in record time.

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    Sketch of Typical Engine Showing Control Station

    Engine Control Station
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    What did I learn from this?

    This is hard to quantify. I had been trained as a Senior Watch Keeping Engineer to obey the engine room telegraph – as the marine communication from bridge to engine room. I had done this and caused a great deal of damage to the ship's propeller. Had I not have obeyed the telegraph, maybe worse would have happened as we didn’t know what was taking place topsides.

    One thing is for sure, I learned that I should have tried harder to understand what the Chief was trying to tell me, and so I ought to have calmed him down a bit before starting the engine.