Is this what happened to the MSC Opera? I don’t know anything about Italian accident investigation.
The GPS systems used for seismic survey vessels are not off the shelf models and are monitored by three independent DGPS systems. The system is usually verified by surveyors using datum points in the port area and theodolites. It is a bit of a pain in the arse because the ship has to leave the berth and berth the other side to during the operation, disrupting storing and bunkering.
Don’t make this too complicated; a OSV, CSV or Cruise ship is not the same as a small yacht, a Seismic boat, or large cruise ship. They all have different manoeuvring characteristics and different needs of manoeuvrability…
If you need to keep station within a narrow margin use DPS, if you are docking use the Independent Joystick. No more complicated than that.
If you have none of the above, use your ability to handle the boat/ship manually.
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last time i was on the bridge of a cruise ship it had multiple GPS sources and antenna’s on the bow and stern.
They have come alongside for years on the joystick as they have huge propulsion capability.
The crew just used them with a huge chart plotter with a locally edited chart to dock.
There are new relative sensors out there that dont need a transponder on a fixed structure to work.
They only really use the DP to replace the anchor and hold the vessel beam on into the weather for loading the punters at sea
I beg to differ about docking with DP in Fourchon. I have seen many PSV’s backing into C-Port in DP mode. These are usually guys that don’t have much “hands on” boat handling experience to start with. I was hired by Hornbeck to operate their DP-1 boats because I am an “old fashioned boat handler” (from the Port Engineer) so I can hold the boat in position at the rig manually while disconnecting from the rig whenever we trip off from the DP mode. The maritime school graduates were assigned to the DP-2 & 3 boats and these were the ones that would use DP at the dock.
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Geez… that’s at HOS? At ECO that’s termination if the office hears about it.
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That was a few years ago during the last boom cycle. When I was “in training” on a DP-1 boat, the Captain admitted he was not a good boat handler but he sure knew about DP system operations. With the ebb current running hard in Bayou LaFourche, he was having trouble backing in at C-Port manually so he called me to the wheelhouse. He was reluctant to use a lot of power around the dock. ‘Show me what you got’, he says. I applied plenty of power, twin screwing the stern into the current with lots of reverse power and 3/4 bow thruster to keep us straight. I had to slip between 2 PSV’s that were sticking way out from their slips. Once my stern got started into the slip, I slowed the power and we gently backed into place. After that, I did all the manual manuvering while he taught me the ins & outs of DP operations. He said that if I wasn’t there, he probably would have tried backing in with DP, which a lot of guys were already doing. You can tell when they are docking with DP because of all the wheel wash & exhaust smoke while slowly creeping towards the dock.
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Why is this? The DP uses lots of power and has the prop wash “fighting” itself?
Yeah, pretty much. For example, to translate starboard it will put the starboard screw to port and run it ahead, and the port screw to starboard and run it astern. The majority of the forces cancel each other out, but the resultant vector points straight athwartships.
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I was on a conventional- prop & shaft- DP boat, where one engine is always in forward gear & one engine is always in reverse gear. The engines work against each other. The Z-drive boats work in a similar way but seem to not generate as much wheel wash.
With 360 degr. rotating Azimuth drives those has to take care of both the fore and aft motion and transverse motion of the stern, unless there is also a stern tunnel thruster.
I knew a Captain that docked the boat in bias mode the whole time with constant rpms. Not in DP. Just how he did it. Worked ok most of the time. Coming into the slip at C-Port 1 got a little funky with all the wash.
I worked with one like that too. Would yell at the bridge crew if they clutched the z-drives in and out in port.
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For reference:
During the low water period on the Rhine last year, there was an advisory in Düsseldorf to avoid using thrusters and propulsion machinery within a certain distance of the dock (I think it was 20 meters), to avoid damaging the harbor sole. You were expected to coast alongside and bring her to a stop on a thrown warp, and people happily did so with pretty substantial boats, up to approx 3k dwt, partially loaded given draft restrictions.
I would have loved to see one of our DP heroes try that 
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I didn’t know mates knew there was actually a variable throttle…they always seem to treat it as an on/off switch to me! 
Are the rudders controlled independently?
Wonder how hard it would be to implement a redneck DP system on my personal twin screw boat…hmmm, ideas.
There’s always this:
You know it’s professional quality when the DP component is called iAnchor 
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Auto docking systems under development and testing is based on using the same functions as DP:
https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/2564153
Wartsila is introducing their Auto docking system for commercial use:
This is NOT suitable for vessels with ABS Class DPS 0.
How come in the picture the operator wasn’t staring at his phone? All you need to do is hit the “auto dock” button and can quickly get back to leveling up in candy crush or watching youtube videos.
Looks expensive…I’m thinking much cheaper and PLC based
At least with Auto docking it is less dangerous then without. People are too occupied on their smart phones already and accidents happen because of it
Mercury can do the same
L3 designed all this for both of them