What is the longest practical tow distance?

Hey all,

I'm not super familiar with tow boats, but wondering if someone can help me get a grasp on what the longest practical tow length is, for a tow boat pulling, say, a barge.

Suffice it to say that the goal would be to achieve maximum separation between the barge and the boat, so the longer the better - but I'm not sure if there are standard cable/chain lengths, if there are regulations/rules, or what the practical limits are that would bound this problem.

You can assume that the towboat can be sized more or less arbitrarily large (to the extent that it matters) and that I'd need to use commercially available cable/chains.

Thank you!

 

In open ocean, longer is better, with a length of very heavy chain in the middle (catenary) to take the snap out of the inevitable surges and lags inherent to towing.
Tow boats are very specialized vessels, but are called on to tow widely varying loads, so yes, they tend to be extra large and powerful. Most tow companies will own a fleet of various sized towboats.
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2000' - 2500' depending.

Why do you ask?

 

From purely radar bouncing I'd say the ones around here like about 3/4 of a mile, so the 2000-2500 fits. Get a strong westerly and a flood tide in the shelikof with an ocean going tug and a barge with 2 inches of cable 3/4 mile apart but the barge isn2 -300 yards offcenter... barges bring life here but they also make bouys dissapear...

 

Also note two things:
1) Tow bridle length is often adjusted to sea conditions to minimize snap loading, as well a shortened up for maneuvering.
2) Often in open ocean tows there are multiple barges in the tow string. In this case, the last barge could be more than a mile behind the tow vessel and well separated from the preceding tow....(and therein lies a sea story....)

 

Several years ago, while sailing just outside the Golden Gate, I observed a tow.
The tow line appeared only perhaps 1/4 mile, (if that,) while the tug was passing under the bridge, but soon after getting into open water they let out line to what seemed to be about 2/3rds > 3/4 of a mile.

 

It comes down to how much cable you can put on the drum, safely.
Bigger tow boat, bigger drum, bigger horsepower, bigger (diameter) cables.

 

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