DP Incidents Oct/24

Introduction: ?Maybe, it was a good month.? Maybe, I was too busy.? Even my industry contacts were coming up bare.? I only had a couple DP incidents, and a few more non-DP incidents, until IMCA released DPE 03/24.? It’s always good when IMCA releases a DP event bulletin, and was just in time.? It’s time to look at some of the DP related incidents and reports over the last month.? These will be broken into “Rumors”, things that actually happened but with limited information or sources I can’t share, ”Non-DP”, things that can happen on DP ships but didn’t, and “Reports”, documented findings.? It’s important to realize that we are not smarter, luckier, or better than the people that these happened too, and that we need to put ourselves in the place of the participants, so we can take each threat seriously.? ?We need to remember that each incident could have been us, and protect against these expensive lessons.? If you have limited time, then jump down to the picture of someone reading a book and follow the first link after it to DPE 03/24.

?

“Rumors” – actual DP events but limited info

Old DGPS:? A couple years ago, I worked on a new build DP ship FMEA with DGPSs that I wasn’t familiar with.? I wasn’t given the DGPS documentation, but I tracked down the make and model online based on the antenna shape in the DP drawings.? I was surprised to find out the DGPS was already beyond its end of life.? It couldn’t be ordered, shipped, repaired, or supported, before the vessel was even built.? The vendor was shocked and showed that they were using a later DGPS that was still good for a whole year.? So, I wasn’t too surprised to recently hear about a different vessel that had related position keeping problems.? In this case, it was due to a combination of old satellite and old DGPS system.? Both were beyond their end of life and notices said they were no longer reliable.

Obsolescence:? Modern equipment becomes obsolete quickly.? Electronics are almost throwaway items, but safe ship operation depends on those items.? The related systems that used to last decades, now only last years.? I was really impressed with Kongsberg’s support of an ancient DP control system on an early drill ship (they brought the original engineer out of retirement - that’s doing things right and what I was used to in other industries).? In contrast, I was concerned about one of their competitors, whose DP system components were no longer made before the ship was built.? Systems are much more time limited and disposable now.? Go check for end of life notices on your old DGPSs and check that vendor specific correction sources haven’t put out similar end of life notices.? Really, this should be an annual process for all important control systems.? Set a date and put it in your planned maintenance system.? On that date or soon after, the ETO or engineer needs to review the current status of all equipment and look for software, hardware, and support service warnings.? It’s better to track and manage the risk than to get surprised in the field by a known and documented problem.? People often forget that systems don’t just need maintained, but increasingly need replaced.? Many electronics age, and capacitors dry out.? Digital dies increasingly faster.

?Blackout:? There was a well-publicized blackout and loss of a DP2 vessel.? The public knows it happened, but I’m listing it as a rumor because we don’t yet know how or why it happened and what we can learn from it.? The DP2 survey/dive ship was working in the South Pacific when it blacked out, drifted onto the shoal it was apparently surveying, flooded, inclined, caught on fire, and sunk.? The crew of the HMNZS Manawanui all escaped to Samoa.? This was a four DG diesel-electric design that was originally the Edda Fonn (2003-2018).? It was still in DNV DYNPOS-AUTR class when sunk (DNV ID# 24192). ?There will be a partially public NZ enquiry.

“Non-DP” - didn’t happen on a DP vessel but could

?

PRM:? A good video example of parametric rolling was shown and discussed in this post.? One of the responses had a good link to the Marin page on the subject with videos and further explanation worth looking at.? I also like this video.? Waves can excite DP vessels too, but we also worry about exciting the DP control system, and change heading and gain to avoid, or go to joystick to overcome position loss.

?

Surveyor’s Nightmare:? The BESS, non-DP, party boat, Oceandiva London, was undergoing propulsion safety trials when it lost control and collided with a barge.? Trials tested battery capacity and then tested full propulsion forward with just one of the two battery banks at a time.? While testing the last battery bank, they lost one main prop and lost control of the other (brownout control malfunction?).? The UK preliminary report thinks the problem was the crew and surveyor not understanding the limits and function of the system.? I don’t understand how you can drain the batteries and then try run them at full load without charging them.? DGs can demonstrate their capacity without being degraded, but I worry about draining batteries too deeply and limiting the battery life and capacity with testing.? Surveyors need to understand the systems that they test and be able to explain the tests, risks, and risk management to the crew.? The crew should know their ship and have the right to be uncomfortable and say “No.”? It may delay testing and future work, but it is better than damage.? Not testing is a risk, and testing improperly is a risk, but even testing properly is a managed risk, as there can be hidden faults.? People, who don’t understand equipment well enough to troubleshoot it, need to question if they should be testing it.? I worry about the people doing DP trials who don’t understand how equipment works and can’t see it going wrong.? I worry about understanding DP systems and make sure I understand them before I test them.? It’s not a generic process that you can throw anybody at.

?

Operator’s Nightmare:? The MTSB report shows the captain of a barge needed to use the washroom and both he and the deckhand thought the deckhand was alert and had him takeover.? They were wrong, the deckhand fell asleep over the wheel, and the barge crashed through a dock.? I’ve written before about the need to make sure that people get enough sleep.? It’s a good business decision that lowers risk and liability.? Some people like to trade money for increased risk and try to manage it with technical solutions.? That seems to be the case here, but the sleep alert system didn’t work, because there was a dangling radio microphone triggering the motion detector.

?

Huh?? The MAIB report shows why a fishing boat was grounded and lost.? “Fishing boat! We run big DP vessels and would never make the same mistake.”? It gets better.? The watchkeeper left the bridge because he was expected to have tea ready for when the vessel arrived in port.? He had to return to the bridge to reset the watch alarm, distractedly made adjustments, returned to his important tea task, and the ship grounded.? Not leaving the bridge underway and not distracting the watchkeeper with other tasks should be obvious, but had become a normalized risk that finally came due.? DP application:?The DPO is not an unemployed body who is available for other tasks.? He is a vital safety element that should not be distracted during critical redundant operations.? Has it become normal to distract the DPO from his main task with other duties on your vessel?? Don’t let the convenient overcome the important.

?

Fire:? IMCA Safety Flash 20/24 had a collection of fire related hidden failures.? Hidden failures are given lip service in DP FMEAs, because there are so many of them possible, but they are still vital and need caught by good maintenance and testing practices.? Everything can’t be alarmed, but everything still has to be safe, and that comes down to good practice.? The safety flash had some good examples:

• Engine room destroyed by fire due to the combination of misaligned engine high pressure fuel pipe connection causing a leak, the leak detection being clogged, and the drain line being clogged.? This was made worse by a closed water mist valve, the dampers not fully closing, and the smoke being too thick to get to the quick closing valve panel.
• Smoking exhaust gasket found to be too low temperature for task.
• Inspection of a 10 year old CO2 extinguishing system found the cylinder connections blanked off, so the system wouldn’t work.
• Arriving for flag state inspection, after a major refit and voyage, the safety pins were discovered still installed in the CO2 cylinders, so the system wouldn’t work.
• Brownout triggered malfunction of fixed fire fighting system and caused it to dump its contents.
• Cracked weld in an exhaust pipe released gas that ignited material in the adjacent stateroom.

A colleague looked at this report and commented that Engine Room cable routing and fires often combined disastrously, with loss of vessel control in three cruise ships, a well know DP construction vessel, and a DP new build just after trials. DP FMEAs avoid listing tens of thousands of potential hidden failures by assuming good maintenance, testing, and operation.? As the examples show, these assumptions aren’t always valid. ?Operator beware: you must make them valid.

?

“Reports” - DP findings from public sources

?

IMCA has released another of their semi-quarterly DP Event Bulletins.? These love letters to safe DP operation are excellent reading with important DP lessons that we as an industry seem to be in constant need of relearning.? I recommend regularly reading them, and contributing to industry knowledge by reporting incidents to IMCA for their confidential analysis and public sharing of resulting lessons.? DPE 03/24 can be found HERE, and so can the bulletins from 2014 to 2024.? Make yourself familiar with them.? I’m going long, and you must read them yourself, but here is an overview of DPE 03/24’s contents, if you wander back:

?

Event 1 - Blackout Automation: ?I’m not a fan of power management systems (PMS) due to the general lack of common sense in their application and testing.? While some love them for their promise of improved efficiency, I look at them as a potential cause of failures, due to the compromises & assumptions made, and a common lack of proper testing.? I have previously defined PMS as a form of effective automation used to efficiently produce blackouts without the crew having to do it.? This event is one of many examples over the years.?

Event 2 - Waving Goodbye: ?Ships use dynamic position control based on limited information and sometimes wrong assumptions.? Operators need to understand those assumptions, so they can recognize when they aren’t true and act.? Some vendors have been pushing the “perfection” of their equipment too hard, and too many new DPOs have believed it.? The DPO is there to make up for sloppy design.? This event is one of many examples over…

Event 3 - >600 Blackouts/Year:? If you have been reading my stuff for a while, then you understand the reference.? This incident is the cause of my fuel discussion in the Aug/24 DP incident article, but I didn’t provide any details, because it was information that I wasn’t supposed to know. ?Go read the fuel paragraph of that article, and the fuel articles linked in it.? We are far worse with fuel than we think and need to start taking it seriously.? This event is one of many…

Event 4 – Jump Around:? This is a fault that I haven’t covered this year, but DPE 02/22 event 4 and DPE 02/21 event 3 had analogous faults.? Deselect failed position references before they can mess things up.? This event is one of… (Anyone see a trend?)

Drill - Full Thrust:? Thruster failure to full thrust is forbidden in IMO 645 & 1580, and in the class rules derived from them.? Nevertheless, many ships lack the required DP protections against this and many older ships explicitly depend on operator intervention to stop loss of position.? In all ships, failure of a thruster toward full thrust must be demonstrated as survivable.? This is explicit in the MTS annual trials gap analysis, but implicit in the requirement for “no single points of failure” in all rule sets.? IMCA recommends practicing this, which I think is excellent advice.? Unfortunately, they only talk about testing CPP thrusters.? The VSD failure mode is far worse, also must be tested, and is harder to test. ?I recommend any ship that hasn’t performed CPP or engine or VSD failure to full thrust trials do so.? It should be done at least annually.

?

Conclusion:? We can get mad and claim that we would have never made these mistakes, but we are no better than the people that these happened too.? The old hands will note that most of the incidents are familiar faults that we have encountered again and again.? I encourage everyone to become familiar with the old faults and to report faults, so we can make less of them.? I hope you have found something interesting and useful that you can apply to make your own work safer.