Hi, we had an incident reported to us recently which has started a bit of a debate in the office. A Tug which was pushing a barge (composite), was overtaken in a river by a much bigger and faster vessel. The wash created by the overtaken vessel caused the Tug captain to make the decision to take some speed off.
After taking speed off, the wash of the overtaking vessel hit the Tug and Barge which caused a tow wire to part…
Should the captain have kept the speed on if he was a composite and could have taking the speed off contributed to the wire parting by giving it more play?
Look forward to your thoughts…
How about specifying the size tug and barge, loaded or light, load on the wires, size and type of “bigger and faster vessel”, exact speeds of both vessel, the size of their wake, navigable width of the river, wind conditions, current conditions, visibility, passing agreement, etc…
Without all of the above, it’s pure conjecture.
Hi, 85t tug pushing a 50m light barge (234t). It was a ferry which overtook (size not specified) which passed 0.2 nm down its side with no passing agreement. The Tug was doing 6kts and its estimated the ferry was 12-14kts. Wake estimated 2.0 mts. Visibilty v good.
I just wondered what 'best ‘practice’ was considered when pushing… slow down or not when be overtaken?
Reducing speed seems like the right move to me.
Being hit by the wake increases the odds of something going wrong, reducing speed increases the chances of being able to maintain control or minimizing the damage in case of loss of control.
From an energy point of view slowing down reduces the amount of total energy (speed + the wake) that can create damage if the energy is released in an uncontrolled way.
But then you lose the stead fast of the composite and wonder if this contributed to the tow parting? Fully agree if sailing a ship, but pushing brings a few other factors to consider…?
I don’t know, just taking a stab at it. The captain doesn’t have time to mull things over or make calulations, he just has to make the high probability move giving the limited amount of information and time.
The captain figured there was high likelyhood of something going wrong in that situation and he was right.
If the captain thought there was a good chance the wire would part slowing down seems like the right move to me. Seems like you’re saying he should make a bigger bet on something unknowable.
I suppose it’s possible that your own wake from a higher speed might meet and mitigate the passing vessel’s wake, The few times I’ve witnessed this egregious behavior on the part of an overtaking vessel, the tow units were blindsided by clueless private yacht and crewboat drivers with no warning and there was no time to react
Two meter wake? With the ferry pushing that much water that close, I’d say regardless of the Captain’s actions something was at risk for popping.
I’m gonna go out on a limb here and guess that when you say “in the office” that you’re QHSE and looking for a root cause in the incident? I’d go with the ferry overtaking too close, too fast, and not giving sufficient and proper signaling of his intentions to give your captain ample time to make adjustments to safely reduce the effects of the offending vessel’s wake.
It’s customary for other vessels to give a slow bell while passing a tug pushing barges. It well known that a big wake creates a risk of breaking up a tow, typically parted face wires.
The tug captain was right to slow down. Better to be going slower, when/if a face wire parts. Less risk of parting the other face wire or completely losing control of the tow.
Ferries are also known for thinking they always have the right of way and can hold course and speed.
I was mate on a tug that parted the head lines (one soft, one wire) while towing on the hip at full speed in a low swell. After the head wire let go the tug turned 90 degrees to the barge, parted all the rest of the lines and then the tow wire pulled us over and the barge dragged us sideways for a while.
Night, pitch dark, captain was in the wheelhouse and I was on deck. Not something that I’ll soon forget.
Perhaps the theory is if the tug is pushing, the wires might have less stress than slowing down and having the barges pull ahead on the wires.
You might thinks so, but the wires are tensioned up as much as the winches will pull while pushing ahead. The fendering is in compression. Slowing down is not going to change the tension significantly. A large wake shock loads the wires far beyond the tensioning power of the winches.there is not much stretch in the wires. The winches are locked on ratchets (no brake that can slip). Something has to give.
Waves don’t work that way. Wave interference
I have pictures somewhere of doing unreps where the seas between our ships looked like total mayhem with water pushed up into the air and visually at least appearing to be absorbing and releasing energy by rising steeper and higher.
If the wake really was 2m high, that’s a lot and the ferry should have slowed down. I was a pilot in Houston for many years and every day we had numerous, close tug/ship overtakings with about 50 ship transits and 150 tug transits a day in a 530’ wide channel. The overtakings were always much closer than described in this incident; around 200-300 feet distance.
Having said that, a 2m wake from a ship is very unusual, even close to the ship. Very seldom at 12 knots. A passing distance of 400 yards is a lot in a river. Was the tug in very shallow water? A wake that is barely perceptible next to the ship will crest much larger when it reaches shallow water. (By shallow I mean less than 15’ deep)
What to do - slow down or remain at speed? The tugs around here commonly handle ship overtaking situations which they think might be a challenge by slowing down then putting the throttles all the way down just before the wake arrives. This means the unit is compressed and totally stuck together. Slowing down during or just before the interaction only loosens things up, creates space between tow elements, increases the strain on the lines and allows the unit to flex.
Not discussed are several things which might have contributed to line breaking. It sounds from the discussion that such overtakings are not common. In places where they are common special attention is paid to the tightness of the the lines and they are at least doubled if not tripled. No mention was made of the tug’s steering action during the incident. A hard over to hard over steering sequence puts tremendous lateral strain on the lines. Could that have contributed?
Last - a tug with only one empty barge very very very seldom has line breaking issues around here. It’s almost unheard of. There is just not enough weight involved to break lines if the unit is made up properly. The units we watch out for on the ships and take care with are long tows of two or more barges in length and heavily loaded.
COLREGS Inland rule 9:
(i) In a narrow channel or fairway when overtaking, the power-driven vessel intending to overtake another power-driven vessel shall indicate her intention by sounding the appropriate signal prescribed in Rule 34( c ) and take steps to permit safe passing. The power-driven vessel being overtaken, if in agreement, shall sound the same signal and may, if specifically agreed to take steps to permit safe passing. If in doubt she shall sound the danger signal prescribed in Rule 34(d).
Inland Rule 34:
( c ) When in sight of one another:
(i) a power-driven vessel intending to overtake another power-driven vessel shall indicate her intention by the following signals on her whistle: one short blast to mean “I intend to overtake you on your starboard side”; two short blasts to mean “I intend to overtake you on your port side”
You wrote above: "Two meter wake? With the ferry pushing that much water that close, I’d say regardless of the Captain’s actions something was at risk for popping._
I’m gonna go out on a limb here and guess that when you say “in the office” that you’re QHSE and looking for a root cause in the incident? I’d go with the ferry overtaking too close, too fast, and not giving sufficient and proper signaling of his intentions to give your captain ample time to make adjustments to safely reduce the effects of the offending vessel’s wake."
I was replying to that post originally, but when I saw that my answer to you would not appear next to your post but at the bottom of the pile I decided that would be too confusing and deleted it. You replied to the deleted post before I got to it.
What I had to say in the deleted post was that in pilot waters an overtaking at 400 yards is not often considered a matter that requires a formal passing arrangement. The rule you quote above does not add to a discussion between experienced mariners. There is an element of “risk of collision” which your quote ignores. Overtaking a tow 400 yards away in a river 3/4 of a mile wide does not necessarilly mean there was any risk of collision and the lack of that communication did not contribute to the accident under discussion.
I wrote a more complete post above if you are interested.
And forget about “root cause” stuff. Anyone who thinks there is an original or “root” cause to accidents has never seen the roots of a real plant (or accident). They are bundled, entertwined, complex, and numerous.
I don’t think the COLREGS would apply to wake damage necessarily. Here’s what the CG says
- What are the regulations concerning wake effects, wake damage, and responsibility? Regarding one’s wake, vessels over 1600 Gross Tons (GT) are specifically required by Title 33 CFR 164.11 to set the vessel’s speed with consideration for…the damage that might be caused by the vessel’s wake. Further, there may be State or local laws which specifically address “wake” for the waters in question.
While vessels under 1600 GT are not specifically required to manage their speed in regards to wake, they are still required to operate in a prudent matter which does not endanger life, limb, or property (46 USC 2302). Nor do the Navigation Rules exonerate any vessel from the consequences of neglect (Rule 2), which, among other things, could be unsafe speeds (Rule 6), improper lookout (Rule 5), or completely ignoring your responsibilities as prescribed by the Navigation Rules.
As to whether or not a particular vessel is responsible for the damage it creates is a question of law and fact that is best left to the Courts. For more information, contact your local Marine Patrol or State Boating Law Administrator.
Bluntly, I am saying that wake probably did not cause the damage and a failure to exchange passing signals certainly was not a factor. The wake might have been a contributing factor, but the reported speed of the ferry was not out of the ordinary, the tug might have been in very shallow water, the lines probably were scanty and not as tight as they could have been, slowing down put greater strain on the lines, and the captain, reacting to the wave might have used an excessive amount of rudder. Removing any one of these factors could have meant there was not an incident to write about.
Of course this is all speculation, but based on a 40+ year career navigating large vessels in narrow channels. The OP was asking if slowing down was the correct thing to do and asking for “thoughts”. Slowing down probably made things worse and there are other factors to consider.
I think the OP was looking to throw the Master under the bus for the incident and was looking for some anecdotal evidence on here in order to do so, but that’s just my take.