Cruise ship Viking Sky in problem

[Pilot16]

Excellent technical response, I appreciate the time in noting all your questions , too. Many are the same I have rolling around in my head. As you imply, this could not have happened so ‘suddenly’ and without warning or at least a history of happening before (alarms going, yes, ok, hit the “ack” button and go take a look).

The manual you refer to, is obviously going to be scrutinized (I would think) by so called regulating authorities and to see whether the watch engineers onboard were attending to engines “in accordance to the instructions”…at least as much as the instructions told them what to do.

Your comments about the dry sump or wet type are well noted. Again, these “marinized” diesel engine plants (of considerable size) I have always assumed were purpose built and designed to work continuously in an environment where it is moving, rolling, pitching, etc. Therefore, one would think that these manufacturers (certainly the engineers operating in such conditions) are reviewing the instructions, manuals, etc, about how to address this issue.

Finally, as a CHENG I know you would appreciate this… I’ve worked on tugs that were on some excruciatingly rough conditions between the islands in Hawaii. They are not long runs (longest tow maybe two days) but even an overnight run, the tug is subjected to large rolling, huge, deep pitching, yawing and swaying. The engines down below (all typically 4000-5000 HP) are subjected to such heavy motion.

So having had that experience, and thinking how we never had a “low lube oil” issue in such conditions, makes me fail to understand why larger ships are having this issue now? It’s not that the industry doesn’t have that experience base. But wondering if certain manufacturers or builders have lost the expertise to design and build it just right?

Or is there something else altogether they might not be sharing publicly???

[ombugge]

@Pilot16

The manual you refer to, is obviously going to be scrutinised (I would think) by so called regulating authorities and to see whether the watch engineers onboard were attending to engines “in accordance to the instructions”…at least as much as the instructions told them what to do.

Yes the so called “Regulating Authorities” (in this case NMA) and investigative entity (AIBN) will scrutinise manuals, electronic logs and other relevant material.

They will also interview all persons involved, both those on board and ashore, incl. machinery and equipment manufacturers and all other relevant persons that may be identified during the enquiry.

This will be done, not to find someone to blame, but to identify the direct and underlying problem(s) in order to avoid a repeat on other ships.

The lessons learnt will be shared with all relevant parties, either directly to the parties involved, or through multinational organisations. It MAY even end up in new rules and regulations by IMO for all member states to implement.

Those who followed what happened after the Alexander Kielland and Bourbon Dolphin accident would know how this is done.

[DeckApe]

@ombugge

These pilots are used to land and take off from heaving/rolling helidecks and in higher wind speed than here as a matter of routine, but that is on rigs and vessels with trained HLOs etc.

That I’ve seen the rules for air capable ships have landing limits such as no greater than so many degree pitch/roll and so many knots of wind from such a direction. I’d think the deck of a rig compared to a foundering ship in a storm isn’t the same. The danger isn’t the landing, it’s once it’s landed on a dynamic deck. This has nothing to do with skill or routine and more to do with physics. An aircraft on deck can bounce or skip, the blades can bend and touch deck or touch someone’s head. It’s much safer to remain airborne where pilots can stay away from the dynamic ship and can quickly power up and away if danger appears.

[ombugge]

On rigs and offshore vessels there are rope nets stretched on the helideck to reduce the risk of skidding after landing and before wheel chocks can be positioned.
In the situation I described the Floatel was a semi-submersible laybarge and the platform the Statfjord B in 1981:

The operation of shuttling was routine every time the gangway had to be removed due to weather. 150-200 persons transferred each way by 3 x S-61 choppers in 1-1.5 hrs.

In the case of Viking Sky there were no helideck, or designated winching zone (AFAIK), thus the procedure was decided on the fly.

PS> I posted about a storm on Statfjord B/ LB 200 here:
Pictures of 70+ foot seas

[Kennebec_Captain]

If the assumption is made that the low oil level alarm was measuring oil levels accurately, and that it is correct that that the actual oil levels were above the required minimum as stated, than:

There should have been no lube oil low-level alarm and there was no reason for the engineers to think the they needed to add lube oil. This is true even if the oil pumps were in fact sucking air due to a design flaw.

[KPChief]

@Kennebec_Captain

There should have been no lube oil low-level alarm and there was no reason for the engineers to think the they needed to add lube oil. This is true even if the oil pumps were in fact sucking air due to a design flaw.

Of course you are right, no alarm no reason to take action. But…

If functioning correctly the low level alarm comes before the suctions are uncovered within the stated trim and list limits.

If a float hung up indicating not-low level but the level went down over time to the point ship motions at or beyond the design limits caused pumps to suck air and low pressure shut-down this raises a few questions like; was no one was checking level by stick? Could all 4 floats stick and engines consume oil such that all 4 shutdown near simultaneously?

A level alarm typically has a suppression time delay to tune out on/off nuisance alarms for rolling or normal trim/list variations. Could this feature have been abused? Where it became normal to increase the suppression time to get rid of the alarm vice just go checking manually or to make a change request to physically alter the float location? Someone(s) kept increasing the time until one day ship motions allow suction to uncover before the “wave” of oil reset the float?

I don’t believe it is possible for any reputable operator to engage a crew that is not checking engine oil levels by hand very regularly and building an “experience factor” as to when alarm comes vs level on stick/tape. So I’m curious to see what combo of design, build and operation factors got 4 DG’s to shut-down more or less at the same time.

[Kennebec_Captain]

Well, like you said, not enough info.

But what I’m getting at is that it’s been said that the oil levels were within acceptable limits, above the min and below the max. By stick or by sensor should have read OK.

So they would not necessarily get a low level alarm (averaging the data over time), in fact it the sensors and so forth are operating properly there should be no alarm, otherwise it would be a nuisance alarm.

If the oil pumps sucked air either the min/max was wrong or the ship took a roll beyond specs.

[ombugge]

Viking Sky left Kr.sund at 1550 hrs. L/T bound for Copenhagen. At the moment she is making >18 kts. and steaming south, keeping well off the coast.

PS> She is due here in Aalesund several times during the summer season. First visit already in early May.

[camjournal]

Yes KC, as you and KPC have said not enough info, but I think you’re on the right track. The L/O sump low level alarm is a bit of a red herring. The response to receiving a low level alarm is to sound the suspect tank and the others but if the levels are within the limits, and the vessel is in a seaway, then it’s reasonable to decide that it’s due to the oil sloshing around. A low L/O level alarm is not to tell you that the pump is about to lose suction, it is supposed to be set well above that point for all trim and list limits. I’m willing to bet that the EOOW could have told you what the M/E oil levels were right off the top of their head without looking at the dips.

A large pax ship with propulsion and stabilizers working, sailing in weather it was designed to handle, should not have problems such as the L/O pumps gulping air. Yet this appears to be what happened and I’ll bet the engineers were as surprised as anyone that it could happen. Possibly a bad roll combined with L/O levels near the low range - these things are always a combination of events. It seems to be something like this as all the operating engines were affected.

Injunear’s comment about losing CAT 3612’s (similar-type engines) to the same issue and lowering the suction piping to fix it is very interesting. If I had designed the Viking Sky installation I’d have been in the office first thing Monday morning checking my calculations.

But once the propulsion shuts down things change a bit - for the worse. Now you’re wallowing in the trough with uncontrollable rolling and I can imagine the engines starting but then gulping some more air and shortly shutting down again.

We’re speculating of course, but it’s sure good to look at these scenarios without having to actually experience them.