Don’t know, from the way the water piles up ahead of the prop it looks like astern the whole time. Which is not surprising, given the situation, be tough to make a quick little two-step at that point.
As far as the black smoke, be a question for an engineer. The engine is normally directly controlled by a micro-processor or some such. So presumably it would go from astern to stop to ahead in accordance to it’s programming. The black smoke might be from the EOT being on crash astern where the programming rules would control the engine in a different way than normal engine orders.
Most ships when going astern don’t react on the rudder, whether hard to port or starboard. However, there are exceptions such as the K-series of Shell tankers. I sailed on three of them. We didnot discover that but a Panama Canal pilot did! When he boarded he checked how the ship responded on rudder and engine commands. I thought that it was a wise thing to do but the captain just shrugged…
When going full astern he also ordered hard to port and starboard. A few moments later he started shouting from the bridge wing: “She is steering, g*^#it, she is steering”. We all trooped outside and indeed the ship while going astern listened to the rudder. On one side easier then on the other but nevertheless. He had never seen that he said, neither had we for that matter.
I had a pilot try the same thing. Normally with stern way the ship is steered with the bow thruster. The pilot said some ships will answer the rudder with stern way and some not. Calm day with no wind our ship would not answer the rudder, at least not that we could see.
In this case the ship was going ahead with the engine astern. In this case the rudder will be surrounded by churning water, doubt if the rudder could develop lift to any significant degree in that situation. Normally the practice is just leave the rudder adminships.
I agree the rudder position will have negligible effect with a reversing prop if the ship is either stationary or backing down however this ship is moving forward possibly with enough speed/steerageway for flow to have an effect. Just an observation. With the rpms in this instance causing so much turbulence, a different rudder position probably would not have affected the outcome by much.
If you need the tug to come in and push quickly (such as when docking) then yes. Otherwise, once stretched out and tight, long line leads keep the tug’s wash from hitting the ship’s hull and keeps the lead angle of the line flatter (ie, line tension is more efficiently translated to effective bollard pull). Regardless, in this case, most tractor tugs are going to be overwhelmed trying to pull at a 90 with much effectiveness at 5-6 kts of headway (unless working indirect).
Each ship is different. For the rudder to be effective it needs a certain water flow to create a high pressure on one side of the rudder and a low pressure on the other side. When going astern there often is no such flow but turbulent and aerated water. It all depends on many things like the shape of the hull and is hard to predict.
Yes, IIRC that was exactly the context of the discussions. Pushing in at a 90 then wanting the tugs to stretch out to check the speed as the ship got close.
I was thinking about the situation where the aft tug is made up on the centerline on a short lead. They can swing from pulling to stbd or port to putting on the brakes quickly.
I see that aft tug way out on a 90, I’d think it’d take forever to swing astern to put the brakes on. Maybe irrelevant in this case, made up on the quarter? Or just not the practice? The centerline make-up I see more in Europe and some U.S. ports. Not in Pusan but I can’t recall for sure.
That the vessel was in ballast with only three quarters of prop immersion resulted in the transverse thrust to port from a fixed pitch right hand propeller being more pronounced. The rudder is largely ineffectual because it was partly submerged in aerated water from the astern movement. It is generally not a good move to move the rudder from amidships in a large ship with stern way on unless the engine is already running ahead. It exposes the rudder to large forces.
Bow thrusters are pretty ineffectual at speeds above 5 knots. They work well when vessels have stern way on because the pivot point moves and they have more leverage.
Guy was going too fast on approach for whatever reason. (Perhaps mechanical)Took many tools out of his bag that he could’ve used had he been a bit slower. Old timer once told me “Go slow, if you have a problem, you do thousands, If you go fast, Hundreds of thousands.” That was a long,long time ago. Multiply that by whatever number you choose in this day and time.
That’s what I was thinking. Making initial approach at 8 knots and final approach at 5.5 knots with a ULCV seems like a mechanical issue to me, not operator error.
Wise words! A master should always take certain actions before and during berthing. There are some important golden rules to follow :
Slow the speed
Control the approach
Planning
Preparation
Briefing
Team work
Checking equipment
He should always brief the bridge team to ensure the officer of the watch (OOW), helmsman, lookout and pilot are fully aware of the expected manoeuvres and the likely effects of wind, tide and current.
Always ask the pilot to discuss the passage and berthing plan.
Always have your anchors ready to let go and forecastle manned in advance of berthing.
The problem I see with the mechanical problem story is the track. If they couldn’t control the speed why didn’t they take a different track? Why didn’t they say further off the pier? They had all kinds of room to stop a little further out.
Not disagreeing on that point, appears they had slowed down somewhat after turning towards the dock. But for whatever reason , that next to last leg shows a definite speed increase. Jury out on what that reason was. Either way, bad day for all.
