As a mariner here’s my two cents:
While I don’t have exact numbers or statistics, both points you made are absolutely true. ATBs are able to operate with fewer crew. In the deck department for example, an ATB will usually have two mates instead of three, and no wheelsmen, with the mates or captain doing the steering themselves.
Ships have also proven more efficient than ATBs and as you said an ATB is generally more effective on shorter runs. A good example of this would be to look at Interlake Steamship. In the 90s they explored the ATB path and converted one of their steamers to the barge Pathfinder. A few years later in the 2000s, they opted to convert the rest of their steamers to diesel rather than convert into barges. Evidently they chose to stick with a larger crew size over the loss of efficiency. Today the Pathfinder still works on shorter runs, often going several trips in a row without leaving Lake Erie, while the ships converted to diesel continue to haul cargoes up and down the lakes.
Another concern with ATBs, relating to the smaller crew size, is that since they are using fewer people to do essentially the same job, those crew face longer work hours and fewer rest hours when aboard. This would theoretically increase the potential for fatigue and therefore mistakes and errors. Many crew on these units work on a schedule of 6 hours on and 6 hours off. Adequate rest hours are important for ships on the Great Lakes as they make many docks in a week and have fast turnaround times.
Ship vs. Tug/Barge
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Hobieone
Ship vs. Tug/Barge
I've watched this subject since the Wedtech days in Ontonagon when someone got some government money to build these things.
I've watched some of them still plying the lakes.
I was told that one of the objectives was decreased manpower due to them being a "tugboat" as opposed to a "ship", which I guess was part of USCG regulations.
I was told by some others that the hydrodynamics of the T/B arrangement made them LESS efficient that the Ship equivalents. Hence they were relegated to shorter runs and quicker turnarounds.
Can anyone elaborate on these points.
I've watched some of them still plying the lakes.
I was told that one of the objectives was decreased manpower due to them being a "tugboat" as opposed to a "ship", which I guess was part of USCG regulations.
I was told by some others that the hydrodynamics of the T/B arrangement made them LESS efficient that the Ship equivalents. Hence they were relegated to shorter runs and quicker turnarounds.
Can anyone elaborate on these points.