Great Lakes Self unloaders - Ships Nostalgia
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Great Lakes Self unloaders

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  #1  
Old 12th April 2019, 22:57
lakercapt lakercapt is offline  
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Great Lakes Self unloaders

Great Lakes Self Unloader

One of the most efficient cargo boats is the Great Lakes self unloader.
This is a specially designed boat that has the ability to discharge its bulk cargo without the use of shore facilities and does it without the need of any shore based personnel.
It is usually loaded with a variety of cargo such as coal,iron ore pellets,stone,cement clinker,grain of different types, potash and salt and almost anything which can be classed as bulk.
Most have several holds so a mixture of cargo can be carried and it is when the receiver wishes a blend this option is available.
Most loading is done from shore based facilities but it is not unusual to load from another selfunloader.
It is the discharge when this special boat comes to its own. As Mentioned previously this is all done by the ships crew.
At arrival at the discharge place (I don't say berth for reasons mentioned later) the mooring is done by landing crew members on the dock. Unlike deep sea vessels there are only four wires (occasionally six) used and they are from for'd one and two, and aft three and four. These wires are attached to self tension winches so after mooring they are switched to automatic.
The unloading boom is swung ashore, This is about 250feet long. To do this it is necessary to start ballast going in to an offshore tank so the boat stays upright. To assist this there are indicator lights positioned for'd, aft and in the engine room control room.
These lights are arranged as follows. There are five lights on each display. White light n the middle and two red light for port and two green light for starboard. When the boat is upright a white light is on. If a list to port then a red light comes on. Red flashing indicates ˝ degree to port, a solid red light one degree one fixed red and one flashing indicates one and a half degree and two solid red is two degree list. Hope this is a sufficient explanation. It is important as the boom is very heavy and itsessential to make sure it does not come loose.
One mate is stationed at the bottom of the boom at all times and he has an emergency stop bottom in his hand and should he see anything untoward he can shut the whole system down immediately. There are numerious walkie talkies for constant communication. At the base of the boom is the control room where the electrician sits and he is the person who controls the rate of discharge by monitoring the load on the electric motors. There are several depending on if there is a two belt system in the tunnel or three. Then there is the loop belt which brings the cargo from the lower hopper to the hopper at the base of the boom and last the boom belt motor.
Before discharge starts the mate gives the electrician the sequence of discharge and then the tunnel men on the bowls of the boat open the gates accordingly. These hydraulic gates can be open fully or partially depending on how fast the cargo flows. If if flows too fast and loads the belt too much the electrician indicates to tell the tunnel men of throttle the gates in. It takes lots f cooperation to unload the cargo and one of the worst problems is if the belt is loaded too heavily and the electric motor stalls. Then its a matter of crew shoveling the excess cargo off the belt till it can go again. If a tunnel man does this he is not a popular guy.
The unloading sequence is very important as done wrongly it puts massive stresses on the hull and there have been occasions when the boat has broken its back.
While this is going on there is another mate monitoring the ballast and watching the cargo holds to see that there are no hang ups with the cargo. The modern lakers have a coating on the hopper sides of the hold so the cargo does not stick. There are a series of vibrators which can be turned on to shake the sides if by any chance cargo sticks.
When the hold is getting close to being empty deckhands are sent down to clear up any ago on the walkways. When they are down the hold one person delegated to watch and has another emergency stop button.
The rate of discharge depends on the type of cargo but with iron ore pellets is is in the region of 6000 tonnes per hour. It varies with other cargoes and I have seen in the fall when the temperature falls below freezing coal cargoes which are wet, taking days as it freezes in the holds and when on the boom belt the moisture coats the belt an the coal slips choking the spout feeding from the hopper.
It is a very coordinated operation and if the crew are experienced it is problem free.
Each cargo has its own special handling , as with potash you can't unload it too fast as it breaks the granules and the receiver is most upset. Clinker is slow as you don,t wish too cause too much dust or the environmental people will shut you down.

On some of the boats you get to berths or should I say discharge places where it requires what is referred to as a “Punt job”. The boat gets near as possible to the place and the punt is sent to go ashore with four deckhands and four heaving lines. There is usually a shore person there to tell out where to dump the cargo and if he is willing to help pulling mooring wires ashore with his truck or pay loader. Depending on the water levels it could happen the boat can't get close enough for the boom to reach. This can mean waiting till the water level rises or the mate loads the belts very lightly and shoots the cargo off. As the boat lightens it is winched closer. I will tell a story about a time we did a “punt job” later.
When discharge is complete the boom is slowly swung inboard and the balancing with ballast is done. Once the boom is in its cradle the power its then switched to the bow thruster and the crew sent ashore to cast off and away you go to the next port.
To give you an idea of how busy we are ,we carried in one season 126 cargoes and some of those were two or three berth discharge points.
I hope my explanation is understood giving you an idea of these special boats.
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  #2  
Old 13th April 2019, 04:35
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kewl dude kewl dude is offline  
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In the 1950s on forward my Dad called Self Unloaders - Self Destroyers.

He felt that sailing them was not much of a life. Alongside only long enough to load or discharge. This was the era of loading ore in three hours, but unloading with shore side derricks taking many hours, providing time for the crew to have a run ashore.

Greg Hayden
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  #3  
Old 19th April 2019, 15:15
LaFlamme LaFlamme is offline  
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Good explanation of the self-unloaders.
I sailed for a brief period of time on the Ontario Power in the winter of 1968-1969. The owners, Upper Lakes Shipping, decided that year to take her out on the Atlantic Ocean for the winter. I was first a Watchman, then quickly was promoted to Wheelsman (those are the terms used on the Great Lakes ships).

She was a wonderful ship, with a crew of a little more than 40 men, I don't remember exactly. The Wheelsmen also operated the boom when we were unloading. I don't know if the procedures have changed nowadays. There is a cabin at the base of the boom, elevated above the deck and right in front and below the bridge, where all the controls to maneuver it are located. It was quite exciting to have that responsibility. At first, we tended to be too nervous with the trim and we would send too many signals to the men operating the gates down in the tunnel. That would drive them crazy. But we quickly learned to be more circumspect with those bells.

Unfortunately two First Mates were badly injured in quick succession that winter, and Upper Lakes Shipping tied up the ship in Philadelphia for the rest of the winter.

I remember vividly those two accidents but will not relate them here. I would be interested though to hear from other crewmen who were there that winter.

After that I sailed on one of the Gypsum ships, also self-unloaders, but sea-going ships nevertheless and engaged in foreign trade. Those ships had a somewhat different unloading system: same tunnels under the cargo holds, same hydraulic gates, same belts, but no boom above deck. Rather there were two large doors in the hull, right in front of the engine room, one on each side of the ship and which were opened when in port, through which a shorter boom extended over the docks or hoppers ashore. On the Gypsum Princess we also carried an extra length of boom that we rigged and swung from two large masts on the stern, to extend the range of the unloading conveyor belt.
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  #4  
Old 19th April 2019, 16:43
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Burntisland Burntisland is offline  
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I was born and raised at Port Boca Grande, Fl. I recall GYPSUM EMPRESS and GYPSUM KING calling there to load phosphate.
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  #5  
Old 19th April 2019, 21:38
lakercapt lakercapt is offline  
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A story about a trip on a selfunloader.
Was nearing the end of the season when we loaded a cargo of limestone to be offloaded at a paper mill n Northern Ontario. The place was up a river near Thunder Bay and asking the crew no one had been there before so it was going to be a new experience for everyone. Went slowly up the river and approaching we realized it was going to be a “punt” job so with much haste it was prepared and off went the four deckhands with the heaving lines. There was a person from the mill there, thankfully to assist and he indicated to dump the cargo on the pile that was already there.
It was fairly late now and as it was far away from the nearest town (Thunder Bay ) no one ventured ashore.
The cargo was discharged on top of the existing pile and when finished we departed never having seen anyone else from the shore.
Next morning we received an unexpected call from the office. “What happened with your last cargo?
Nothing as we discharged it where we were told and sailed when finished.
Well, we were informed did no one look where it was going. It was going where they indicated and we never saw another person.
Oh well, you would not have known there were trucks parked at the other side and you buried four of them!!!
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  #6  
Old 20th April 2019, 00:37
dannic dannic is offline  
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BritishSteel had a pair of converted bulkers to be self unloaders, met up with them in Port Talbot. 2nd mate and 3rd engineer volunteered to operate all cargo gear .....as no one could sleep anyhow. conveyor ran up front of accomodation.
Dannic
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