gcaptain has a post - ATB is Largest Ever to Transit Alaskan Waters, its about the 155,000-barrel ATB, Sea Reliance/550-1. An A.T.B is an "Articulated Tug / Barge.
The question is why is Crowley using this rig, which is 600 feet long instead of a tanker? The answer is manning regulations.
From this article History of the AT/B
As an example a typical U.S. flag, Jones Act Tanker without a large amount of automation to reduce the overall manning requirements would have a crew of about 19 to 27 people. Whereas a typical U.S. flag, Jones Act conventional tug and barge or for that matter an AT/B with a tank barge, with the same cargo carrying capability can operate with as few as 7 people, but seldom more than 10.If a 600 foot tanker is required to have 20 crew members why is this rig safe to operate with only 7-10 crew. Either the tanker has too many or the tug too few. I wonder if the mate and captain work 6 and 6 with the mate doing all the cargo work?
Defenders of AT/B claim that they are not "rule-beaters" but have advantages over ships beyond lower crew and construction costs. If that was true wouldn't you expect to see them outside the U.S.? In fact it is rare to see a tug and barge outside the U.S unless it is a specialized tow.
Japan's inland sea is crowded with all kinds of small ships, LNG tankers, oil tankers, small car ship and container ships. In apperarnce they look like a deep-sea ship, just smaller. Europe is the same way, you rarely see a tug with a barge there.
When we get bunkers overseas it is almost never from a barge but from a bunker ship such as the one below. In the United States on the other hand it is almost always from a barge, pushed by a tug.
Towmasters has this to say about such a rig:
Generally, they’re a proven vessel design and in several fundamental ways they are significantly safer than conventional towing vessels. They’re also more efficient and capable of operating safely in weather that would leave conventional tugs either weather-bound or engaging in unnecessarily risky voyages while trying to compete with the ATB’s. They are not, however, towing vessels in any honest sense of the term. So why should they be regulated as if they were?
For all intents and purposes this is a ship but the Coast Guard has ruled that it is instead, an uninspected towing vessel pushing an unmanned barge. This means that it must meet much lower manning and inspection standards then a ship with the same capacity would.
Sending a load of oil to Alaska by water shouldn't be about bureaucrats and lawyers sitting together in an office somewhere scrutinizing the law hoping the Coast Guard will see things their way. The coastwise route to Alaska is up the Inside Passage and then across the Gulf of Alaska , on of roughest bodies of water on earth. Vessels built to transit these water should be designed for the sea, not to dodge regulations intended to both make the mariners job easier and safer and to protect the environment.
UPDATE: I've edited this post a couple of times for clarity.