Actions when a Tug pushing a barge is overtaken by a bigger and faster vessel?


#22

That was my take too. Hence my root cause comments. I’m getting mighty tired of the “all accidents are preventable” BS that comes out of QHSE departments. On the boats we understand Murphy’s Law. It’ll be a glorious day indeed when the bean counters in the office can get that through their thick skulls that sometimes “shit happens.”


#23

QHSE, HSQE, ESQH. All the same thing and though their stated purpose may be to prove that all accidents are preventable, we all know they exist to try and limit the liability of the company and pin the blame on someone when problems occur.

I have no problem with fostering a safety culture and working safely but there used to be a certain leeway given for the ‘shit happens’ part of going to sea that sadly has gone the way of the Dodo.


#24

If I may put two of your comments together, slowing down early enough to reduce speed and have more throttle available to use during the interaction is prudent and standard practice for overtaking in narrow channels, however reducing throttle during interaction between vessels would likely make things worse.


#25

Same here. Things are much safer these days, but it seems to have been lost somewhere that “Acts of God” do occur. Hell, our Illness report requires a cause description and “measures implemented to prevent recurrence” to be entered. “Sorry, can’t head to sea today, we had a guy seasick last week and our measures to prevent it say that we can’t sail in rough weather.” God help me if I ever get a female crew member that feels like sassing the office as much as me and has me file an illness report for menstrual cramps. That would seriously make my day to file that one and watch QHSE squirm. :rofl:


#26

The overtaking vessel and any vessel is responsible for its wake. The overtaking vessel should have made a call to the Tug and Barge, to make passing arrangements. Had the overtaking vessel made the call a safe speed for the overtaking vessel could have been discussed. The Tug Operator did the prudent thing by reducing speed.


#27

Right on! (almost), firstly, most pushers run at too high a power percentage (usually flat-out 100%), leaving no ability to compensate in a case like this by going full out.

Secondly, as is always over looked, tug/barge wakes differ dependant on many things, relative to tug/prop/efficiency/hull drag/stern ramp/on and on, and, the same goes for a passing vessel having a wake form of its own.

No one …repeat three times, ever looks back at their wake so the tugs v form is unknown here, when a inefficient hull passes at much higher speed my experiwence is it is not the passing vessels wake that disrupts ( the tug can go to full and compensate), but long after the passing boat is clear comes the overtake or collision of these two wakes (which will engulf the tug), here is the 2m wake, and the rolling that would undo the push (especially if out of throttle and losing bow pressure.


#28

I believe that it is more a question of Hydrodynamic Interaction than waves. But ones come from the other!

Vessels’ overtaking in a narrow channel is one of the most complex and dangerous maneuver. Several considerations should be taken into account during such a manoeuvre like the local bathymetry, the horizontal & vertical separation, vessel’s lines, UKC, speed through the water, relative speed differentials and so on. General rules of thumb come from local knowledge, practical experience, lectures and training on simulators.

Nevertheless, I came to some conclusions …

  • Is the overtaking manoeuvre necessary?
  • Overtake is easy while being overtaken is very tricky!
  • Better know on the tip of the finger the hydrodynamic forces sequence generated in an overtaking manoeuvre, so to be in a position to anticipate instead of react,
  • The overtaking vessel must be given the overtaken vessel accord well in advance. If agreed, the overtaken vessel must decide where and at what speed the overtaking will be carried out,
  • I found out that speed over 10 knots in the water, within 100 meters and at a relative speed differentials of more than 4 knots generate too much Hydrodynamic Interaction to attempt an overtaking safely. For example, the overtaken vessel should reduce to 6 knots, the overtaking vessel at 10 knots while both vessels steer as close as possible from the outer channel limit. In our example, the tug is already making 6 knots at full. I would reduce to 4 knots until I start to feel the water pressure coming from the overtaking vessel. Then, I would resume to full 6 knots to get improved steering, as I will certainly need it!
  • Heading, rudder indicator and speed log must be checked all the time,
  • If something does not go as planned, the larger vessel which generate the most hydrodynamic interaction should take the lead and reduce speed to minimum steerage. Collision could be unavoidable, so the more parallel it happens; the less damage will be sustained…

#29

“If I may put two of your comments together, slowing down early enough to reduce speed and have more throttle available to use during the interaction is prudent and standard practice for overtaking in narrow channels, however reducing throttle during interaction between vessels would likely make things worse.”

Yes.


#30

If it’s connected with wires it isn’t a composite unit.


#31

Yes, but it’s still technically required.

No, there isn’t.