Tug Not Working To Stop Ship

The author was quick to blame the pilots. Obvious question (not noted in the article)… how come the tug isn’t working ahead to stop the ship? Could the cause have been engine failure on the tug?

Probably because the pilot didn’t tell the tug to do so.


Just curious:
Are these tugs equipped to stop a ship by pushing against the ship’s submerged bulbous bow?

No. He could have tried to push on the flare and hoped he didn’t slide down the skin of the ship, but he didn’t try that it looks like.

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Hard to judge without knowing what instructions the tug was getting from the pilot.

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To New3m: “Probably” implies that is the most likely explanation. Having worked as a pilot for 30 years I’ll say it’s unlikely the pilot didn’t try to get the tug working. They could have had a radio problem or the tug could have had engine problems. Both more probable than the pilot just forgot they had a tug. Most likely the tug didn’t have a good way to work. As pointed out by Urs and yourself, the bow tug was pretty much useless when a routine maneuver turned to crap when the pilot asked for an astern bell and nothing happened.

In the old canal the ships are made up to big winches on rails (“mules”) that control the ship in the lock. The pilots begged for mules in the new locks but were overruled. The pilots predicted exactly this situation - the bow tug rendered useless by lack of maneuver room. If the pilot can be questioned it should not be for one tug vs two but for putting the single tug forward instead of in a bridle on the stern. But there may well have been other reasons to put her up there.

And if the initial problem was the ship’s engine failure the question that should come up but never does is why are we building ships with only one propulsion unit anyway? How many accidents, how many lives lost, how much oil spilled due to ships being rendered immediately helpless by a mechanical failure. Often a minor failure at that. Twin props/engines are known technology. Jack Devaney makes a good case for twin screw ships in his book “The Tankship Tromedy”.

Bottom line: it was a bad decision not to put mules at the locks and not to be building ships with twin screws, but the inevitable result of these two decisions - catastrophic damage to the gates - will be loaded on the shoulders of a pilot or engineer cited for “human error”.


I am about 99% sure that twin engines, over time, cost a company WAY more than the occasional problem caused by engine failure.
Presumably the ships are about as wide as the lock, so a bow tug is pretty useless to stop progress, they need to tow a stern tug too. Is that whole combo too long for a lock?

It’s because ocean-going ships spend 95% of their time at sea, in deep, open waters and going in a relatively straight line. A single screw, single rudder is going to be most efficient doing that.

The few large, twin screw ships that are around (Polar Tankers and ATC in particular) are built with true redundancy in every sense. They also cost a hell of a lot more but were built to serve very specific markets and regulations.

I hate to second guess another pilot, but, like you, I’m curious why if only given one tug, he didn’t make them up aft (bow thruster inop?). That forward tug was absolutely going to be useless for brakes in a lock. Even with the stickiest fendering in the world, that tug was never going to be able to push against the flare effectively enough to stop it.

I do remember the pilots’ concerns over the lack of mules in the new locks, breaking away from a concept that had worked so well in the old ones. Those concerns obviously fell on deaf ears. So much for listening to your subject matter experts…


From a New York Times piece on the new locks published in 2016:

“Tugboat captains say they cannot safely escort the larger ships because the locks are too small with too little margin for error, especially in windy conditions and tricky currents. In fact, in a feasibility study obtained by The Times, the Panama Canal Authority had earlier concluded that the tugs needed significantly more room.”

I’ll be there in about 6 months but never been through it. From an armchair observer’s viewpoint though, these numbers would support the concern over a tight squeeze.

Nominal sizes of the new canal chambers are 427 meters long (1400’) and 55 meters (180’) wide.
The OOCL UTAH has a reported L/B of 335 and 43 meters (1099’/141’). That would leave 92 meters (302’) total fore and aft for tugs to maneuver.

The Panama canal was built before there were powerful tractor tugs. IDK but could be the locomotive system is just not cost effective. That system required lot of workers, linehandlers on board etc. That’d be a lot of money for maintaining a reliable system using tractor tugs forward and aft.

None of the locks I’ve seen in N. Europe use locomotives. I’ve been though the lock in Bremerhaven for example in gale force winds.

In this particular case it seems odd no tug aft.

LOL…stick to driving ships and let the designers stick to designing ships. Twin screws? Why not 100 screws, and 3000engines, plus an extension cord, just in case.

If this is indeed the issue and this particular vessel could only be supplied with one tug………why would you put it forward and not aft? If the main engine does not fire ahead to get you out of the lock……so what……the vessel remains stationary……if the main engine does not fire astern to control your entry speed into the lock with one tug forward……you are in a world of hurt.

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I was surprised to read about worker shortages there. I expected these jobs to be desireable with good pay and benefits for a local.

My answer to that is golf clubs spend 99% of their time in a golf bag. Why put heads on them?

I can only repeat my suggestion to read the section of Jack Devanny’s book, available online in pdf format, about twin screw ships. He anticipates the objections based on economics and addresses them effectively.

The golf club head is 100% at fault for all of the windows I break. I suggest you read Golfer’s Digest.


All the arguments in the world don’t beat the true facts of cost and efficiency. It would be cheaper to require extra tugs for many ships than to add more propellers.

One other consideration with tug placement for large ships entering locks is the so called "piston effect. As the ship enters the lock the water cannot flow out freely as it is displaced.

A large ship entering a lock sometimes uses a half or full bell because the ship blocks the water inside the lock and prevents it from flowing out freely.

It can be somewhat disconcerting because intuitively it seems the ship is approaching the lock gates too fast but the ship tends to stop on it’s own. Also unless the ship is held in place once stopped it will tend to slide aft as the built up water ahead of the ship flows out of the lock.

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It would appear that operating procedures in the neopanamax locks are a little flexible…….b. “Authority to Override”

“May authorise deviations from the rules. In order to avoid Canal operational disruptions.”

When it specifically states that a minimum of two tugs are to be employed whilst entering the neopanamax locks……EDIT: If it was a northbound transit through Agua Clara then it is a minimum of 3 tugs for this size of vessel.

……which is common sense.

Common sense would dictate two tugs. Long view common sense would weigh canal disruption waiting for the 2nd tug vs lock out of service disruption due to accidents .

It is interesting to note that the Loadstar video ceased when the bulbous bow was just about to contact the lock gate and the vessel still had headway…….