Warning: before you read any further , please be advised that these are my definitions. Others, including the U.S. Coast Guard and maybe some naval architects, may disagree. C’est la vie. I get asked this question often and what follows is my standard answer. It is, I believe, based on sound and clear logic, not regulatory doublespeak or wishful thinking.
There exists a sub-category of towing vessels known as ATB’s. This stands for Articulated Tug & Barge. There is another category of vessel known as an ITB, or Integrated Tug & Barge. They are not, and never were, the same. Nor are either of them, with some limited exceptions, a “tug” in anything but name.
There are very few ITB’s in existence so many of you might never even see one, and they bear no relation whatsoever to a real towing vessel. They were designed from the keel up as nothing more than regulation-beaters, capitalizing on the uninspected vessel-status of towing vessels to get away with lower manning, construction and operation standards. They’re simply small to mid-sized ships with detachable propulsion / control units that are rigidly connected and do not move independently. An ITB “tug” disconnected from its “barge” is a sight to behold: unstable in anything but the calm waters of a well-protected harbor, and having the ability to do absolutely nothing remotely tug-like besides moving about under its own power. Here is an example of one.
An ATB, on the other hand, is a somewhat different story. There are two basic types of them, purpose-built and conversions, and they usually use either an Intercon or JAK connection system. The generally-accepted slang term for them is pin boats, the reason for which should be obvious. An ATB pivots on the transverse axis provided by the pins, allowing the “tug” to pitch separately from the barge.
The purpose-built type are generally not very seaworthy outside of the notch in exposed waters, although some people might try to bullshit to the contrary, and even in protected waters they’re very limited in what they can do. For the most part, unless there’s another compatible barge around for them to move, they’re pretty much useless. The idea of getting out of the notch at sea and taking the barge in tow is sheer lunacy. Unless they’re pre-rigged to an emergency hawser and can just back out of the notch and roll around on the barge it isn’t going to happen. Furthermore, you wouldn’t want to be up in that high wheelhouse getting whipped around by the seas. The probability of seriously injuring or even killing someone while attempting this maneuver would be unacceptably high. Suffice it to say that you just don’t ever get out of the notch on purpose unless you’re in port. Unintended/unexpected pin retractions have occurred on the West Coast and I understand that it was pretty ugly.
The conversions, older conventional boats with new pin systems and upper houses installed, can also be limited in their operational capabilities out of the notch, but it depends on the specific conversion job. Depending on which pin system is chosen, whether or not the hull underwent drastic shape modifications to accomodate it, and whether the new fendering offers adequate hull protection determines whether that particular boat can perform basic barge-docking assist work and/or do conventional alongside towing and pushing. Some can, and some can’t. Towing astern, although maybe a little more more feasible than with the purpose-built ATB’s, is still a dicey proposition. Most of the conversions have had their towing machines removed and only have an emergency synthetic-line hawser and a capstan in their place. As ATB’s become more numerous, captains and mates possessing the traditional towing skills are becoming scarcer. Crews that can do softline hawser work (including deckhands and engineers) are even rarer.
Most interesting to me are the few Bouchard ATB’s that were pinned and yet kept their lower pilot houses and big double-drum towing machines. They look like they can do it all: alongside, pushing and towing astern on the wire, plus some limited assist work if needed. I’d love to hear from someone with firsthand experience with them who could give us a report.
So if these ATB’s can’t really tow, astern or alongside, are they still legitimately tugs? I say no. And that brings up a whole hornet’s nest of licensing/TOAR/manning issues that need to be addressed soon, before an even bigger mess is created. More on this subject later…..
…..later has arrived please see ATB vs. ITB, v2.0