It's a long post, and there will be more to come I'm afraid.
So go grab a large cup of tea or coffee or whatever suits you the better, and find a comfortable chair if you feel like going through this thing.
I'm going to talk about the ship I work on, and a little bit about what's happening inside this rather closed world, and I'm probably going to talk about some of the things we have to deal with on a more or less daily basis. This can very well turn out to become a way too long and probably boring (at least to some) post, so I might even split it into two or even several parts, just to really rub it all in.
Let's just start and see wherever this takes me.
Questions may of course be asked in the comments section below about whatever is unclear (I'm sure there is a lot...), and I'll try to shed some further light onto whatever you may wonder about.
Other comments are of course also very much welcome if you wish.
I have removed the name of the ship from all pictures as I'm showing a bit of stuff from inside where it all happens. Not like I'm showing off any secrets or things like that, but still you know.
The ship.
I have been working on board this piece of steel for a total of 11 years. Two years as a third engineer from 2003/-05 and then I came back as a chief engineer in 2011 and have been working here ever since. I guess this picture was taken not too long after our 2014 yard stay as she seems to have had a quite recent paint job done to her exterior. I also notice the blue tower thing on deck which has been removed now, containers and stuff placed there instead. Unknown photographer, taken from a different vessel in our company.
General vessel description:
The ship itself is by todays standard a rather small Multi Purpose Support Vessel, or MPSV. She was built in Norway, finished in 1999 and was the last vessel ever to be built at this particular shipyard. She is about 103 meters long, 22 meters wide, have a Gross Tonnage of 7400 T and a dead weight of 6350 t. It's a DP Class 3 vessel (more on that later) equipped with two tunnel thrusters in the bow, one retractable thruster just aft of the two tunnel thrusters in the front, and two azimuth thrusters aft. All five thrusters are usually in use when the vessel is in DP operation. For conventional steaming forward, to get us from A to B, only the two aft thrusters will be in use.
All five thrusters are individually powered by big electric motors which are fed by 690 Volt, 60 Hz AC current generated by a total of four diesel engines powering one 2400 kW generator each. The electric power is fed from the generators into the main switchboards where the power is distributed to each and every consumer of electric power on board the ship via smaller switchboards and cabinets around the vessel.
There are multiple quite heavy consumers all around the ship, but by far the biggest will be the aft thrusters (3 Mega Watt each), the forward tunnel thrusters (about 1000 kW each) and the retractable azimuth (about 1200 kW). The tunnel thrusters in the bow is designed to only work directly sideways to turn the bow either starboard or port, while the three azimuth thrusters can turn 360 degrees individually (computer controlled) to keep the vessel exactly positioned above a small point at the sea bed as required when the ROV's are working way below the vessel (at around 2000 meters depth on the field we have been working on lately).
There is also a 100 Tonne capacity crane on deck which draws some power when in use, and of course the accommodation with all the lights and heating in addition to all the pumps and equipment down in the engine room which also draws their part of electric power from the generators.
Below is a few examples of some of the heavier consumers on board. Not all of them, but still you'll get the idea.
The drive motor for the forward Azimuth. Can deliver about 1500 kW of power. The drive shaft is sticking out of the motor on the right side here, but you can't see it in this picture. The two white pipes going into the side of it is the water cooling pipes going in and back out. It's quite hard to make good overview pictures on board as there's always something obstructing the view in some way. The picture is taken from above, so not very informative of size and such. About 2x2x1 meters is my best guess.
The drive motor for one of the two side thrusters, or tunnel thrusters. The drive shaft from this one is going straight down through the upper part of the tunnel and into the gear of the thruster making the propeller go around the right way, creating a side force in the bow area. I think each of these motors are about 1000 or 1200 kW.
I put this one in as well, even though it's not the heaviest of consumers on board. A hydraulic power pack designed with three pumps to be able to adjust the amount of hydraulic oil going through the system depending on the need of power at any moment. It can keep multiple quite heavy machines running all at once if needed.
Not a very heavy consumer either, but it does require quite some energy to keep the insides of the accommodation relatively cool when working in hot climate. This is the AC unit taking care of cooling down most of the living areas on board. We got two of these, as they tend to have some troubles from time to time. We just changed out this units twin machine with a brand new one... it was not very old either. You would expect a bit more than 20 running hours from a unit with a price tag of a very good used car...
This is an overview from one of the two main switchboard rooms. All the power from the generators are going through the breakers and switches inside this area before being fed out to individual and smaller breaker cabinets for the different consumers around the vessel. The power distribution didn't come as an afterthought on board a vessel like this one, even though it's over 20 years old this year. Most of the big breakers in this room is usually remotely controlled from the Engine Control Room, but everything can also be switched and phased in manually the old school way if needed.
You are looking at the hydraulic pumps powering one of the steering gear plants. There are two of these machines, one in each of the aft thruster rooms. They each consists of two completely independent pumps, meaning if one is going bad the other one will start and take over the job. One pump to the right, the other one in the center of the picture. The stuff to the left and in the background is the fresh water coolers for the circulating oil in this system.
It's not a good picture at all, but the grey thing to the left is the 3000 kW electric motor for one of the main thrusters aft. The green thing in the center is the visible part of the thruster itself. Basically there's a horizontal drive shaft coming out of the electric motor which transfer the power via a coupling over to the pinion shaft at the power intake of the thruster, goes inside the green thing via a huge bevel gear and the power is distributed down the main shaft inside the thruster to a bevel gear down in the hub under water and out to the propeller itself. Most of the thruster room you see here is taken up by the power converter for the electric motor (not visible in the picture though). It's a quite fancy thing actually, even though the only part we usually will see are the dull grey cabinets.
A closer view of the top of the aft thruster as were described in the previous picture. The coupling between the electric motor and the thruster is found underneath the aluminium cover on the left side of the picture. The two red things in the lower part are the steering motors for the thruster. There are three of them as one is hidden on the other side of the thruster. They are actually just slow turning (low RPM) hydraulic motors driven by the steering gear pumps I showed you a couple of pictures above this one.
The ID plate for one of the main propulsion electric motors.
And finally a few snaps of the things always at work to keep everything moving as it should. The diesel generator sets which is the heart of the power station. Two of them in each engine room making sure we got light in the bulbs and hot water for our showers at all times.
The Non-Drive end of the engine is where you'll find all the pumps and all the other things which is internally powered by the engine itself. All pumps in this end will also have an electrically driven twin, just in case one of the internal pumps should fail. They are fuel pumps, lub oil pumps, a couple of fresh water pumps (High temp and low temp as these engines got two separate cooling circuits), water heaters, lub oil filters and so on.
A better view of the engine. 9 cylinders in-line, the pump end is furthest away from the camera, with the drive end to the left in the picture. The dark green unit to the left is the actuator, which is controlled by an electronic governor to maintain a speed of 720 rpm on the engine at all times. This is to make sure we always get 690 Volts at 60 Hz out of the engine. If some consumer suddenly needs more power, the rpm will suddenly drop. The governor will then immediately discover the engine slowing down (we are talking fine tuning here, so a drop of only a couple of rpm will be enough for the governor to react) and send a signal down to the green actuator which in turn will adjust all nine fuel pumps to pump more fuel into the engine cylinders to keep it steady at 720 rpm. Clever, huh...?
It's not the best of pictures, but as I mentioned earlier it's not the easiest of tasks to get a good overview of the engine room areas. You are still looking at one of the main engines with it's nine top covers there in the background, the grey exhaust channel to the left, and the generator closest to the camera. The generators are capable of an output of a maximum of 2400 kW each. The main engines around 2600 kW each. The system is designed in such a way that only the numbers of generators really needed will run at any moment of time, but that is also dependent on which DP class we are working in at the moment. Diesel engines are working at their most effective (lowest fuel consumption versus kW of output) when running at around 90% load.
Capacities:
A modern ship hull is of course built with a double bottom and double sides. Between the sea and the inner parts of the vessel there are tanks. A lot of them. Mainly there are ballast tanks used to keep the vessel more or less even, or to keep us a bit lower in the water if we are sitting too high in the water and so on. This is stuff the guys on the bridge are trained to deal with. Down in the engine room we are doing our best to keep them busy by moving diesel and other stuff around in awkward ways. This vessel has a total capacity of XXXX tonnes of ballast more or less evenly spread all over the place.
We also need diesel to keep this thing running. If bunkering all fuel tanks to the 90% mark we can carry about 2500 cubic meters of fuel. There are a few quite interesting mathematic problems I could make up for you to solve involving this amount of fuel and a normal family car... but I'll leave it all to you.
About the diesel itself there's nothing much to say other than the fact that the world finally have put restrictions on the amount of Sulphur we are allowed to have in the diesel we bunker. During the last twenty years the percentage of sulphur has been reduced heavily, and I always try to get the one with the absolutely lowest amount if possible. Some places it's a bit hard to get, but in most cases it can be done.
We don't use heavy fuel in any of our ships, luckily. I will not start to discuss that sort of thing, but just want to say that I think it's about time the shipping industry start to pollute a bit less even though we all are a million times better at that now than we used to be some years back. And we will get a lot better in the years to come. I will try to remember to write a few words about that in a later post. We are still not good enough of course, but everything we hear about alternative power sources might not be the best way forward either. I will share a few thoughts about it a bit later, probably.
Finally we got the fresh water tanks. We don't have a huge capacity for that sort of thing, but you can wash quite a lot of clothes and get a few showers out of half a million liters of clean fresh water. We are producing our own water on board, and on a normal day we produce quite a bit more than we use. We like to run the water production anyway to make sure we got a good buffer of water on board in case we run into issues with one or two of our three independent water makers.
There are also a few lub. oil tanks built into the hull, but these are small compared to the others mentioned above. Maybe something like a total of 40 000 liters of lub oil, but probably a bit less. I'm not the type of guy walking around picking numbers like that from the top of my head. I know where I can find the numbers, which is what counts anyway.
In between some of the tanks and around moon pools etc. there are cofferdams. They are there to make sure we discover if any leaks from tanks should occur, and also to make sure there are extra barriers between two tanks containing fluids important not to mix.
A drawing of all the tanks on board. I'm really sorry about the daft picture due to reflections and stuff, but it was of course impossible to make it better unless taking everything out of the frame and such. I just couldn't bother starting that sort of job. Hopefully you will be able to zoom in and have a look at it, and if not I might be able to send you a better copy if you are that interested...
With every tank drawing on any vessel there will be a corresponding table like this where the most important overview and numbers for each tank is printed. The weight the tank is designed for, the total amount of fluids you can put into it, it's center of gravity and how far above the keel and out to the side that point is (LCG, TCG and VCG), all important stuff to know about when filling or emptying the tanks of a vessel. There's a lot more to know of course, which is why there are huge books full of numbers for each tank on board and how they infect the stability of the ship for every centimeter it's filled. Very boring readings, of course... I might show you some other day.
Well... I just go on and show you the full list of tanks and their capacities. Just dig yourselves into it, or leave them be, whatever you please.
Here we are... the small tanks now. Lub oil, hydraulic oil and stuff like that.
And at last on the list there's the tiny ones... the ones we never think is noted anywhere, but they actually are when starting looking into it.
Power distribution:
A large part of operating engines on a level like this involves different ways to control power and have it sent to wherever it's needed. It also involves always keeping your mind alert to the fact that things are not always going according to plan, and therefore we always have to plan for the worse and have a "safe way out" readily at hand. But that's a long story to be honest, and nothing to start messing around with on a blog.
To be able to control the power distribution and the load sharing between the engines and generators, turn pumps and other equipment on and off, opening and closing of a myriad of valves and a lot of other more or less interesting functions, we got the SVC or Simrad Vessel Control system. This is a computer system which is constantly monitoring all functions, all valve positions, the levels in all of the tanks, the levels in all of the bilge wells around the vessel, hundreds of different temperatures, pressures, which pumps are running and which ones are not, and so on. There are five stand alone computers in this system, and they are set-up in such a way that all five computers are doing the same job checking the same things every second around the clock, every day of the year. This is to ensure that if one or more computers shuts down there will (hopefully) always be at least one working to make us able to run all functions in a safe way. The computers are also physically placed in two completely different locations on board (two on the bridge and three in the engine control room) in case of a major event meaning we have lost a huge part of the ship (fire, flooding etc.).
I'll show you a few of the graphics from the SVC system below. Keep in mind that these are the simple outlines of any of the systems, and not anywhere near the full picture of how things are put together. To see all valves (manually operated) you got to look into the drawings of each system and follow the pipelines to get the full view of how everything is put together.
All pictures and pages inside the SVC system are quite important, but some are a bit more important than a few of the others. This is the main Power distribution picture, and shows us what's running at any moment, how the main switchboard breakers are configured and a lot of other useful information. I will not use time to explain this right now, but will come back to it in another post. It's not that difficult either, so you can probably figure out most of it by yourselves. Green means running, white means stopped. Only one generator is running at the moment at an output of lousy 419 kW and with no thrusters or propellers running. That's because the ship is at anchor as I write this...
Port Azimuth aft. This is the schematics of the azimuth showed a bit earlier in this post. You will see one pump running which is a lub oil pump to maintain lubrication to the big bevel gears. The steering gear is showed in the upper left part of the picture and the cluster of four small oil pumps lubricating the fine bearings of the electric motor is showed just below the motor itself. Inside the motor we can read the temperature in each of the three windings of the motor, and also the Drive End and Non Drive End bearing temperatures. We also have control of the different oil pressures and also the cooling water temperatures among other things. This is the same for all thrusters. To the left in the picture there are two "clocks" showing the direction of steering (upper) and the output power of the thruster in question. All the small squares scattered around the picture is an alarm point which will turn red if there is an alarm state in any of the sensors.
Ballast tanks and ballast pumps which is also acting as fire pumps if you press the right buttons. To open any of the valves you simply select a valve, do a "right click" and select "Open" on the next menu. The valve will turn green in the picture when the feedback sensor on the valve has registered the valve to actually be open. When all the right valves shows the right position you may start the right pump to either fill more ballast, move it from one tank to the other, or simply get rid of it. All the ballast tanks contains sea water. There are strict rules these days about how often the ballast water needs to be changed, and where you can actually pump it out and where you absolutely not are allowed to get rid of it. The filling level of the tanks are marked in green.
These are the diesel tanks. The same thing applies here as it did in the ballast picture about opening and closing valves. The colour code for diesel is yellow as opposed to the green colour for the sea water. You are looking at the cargo tanks here. The engines can not take their diesel directly from these tanks, so we need to use the pumps indicated in the middle of this picture to pump diesel from one of these tanks over to the "settling tank". It will then be sent through a diesel separator to get particles and water out of the fuel before it enters the day tank. The engines are taking their fuel from the day tanks. One settling tank and one day tank on each side of the vessel.
Here they are, the day tanks and settling tanks (upper and lower in the center of the picture) and the two diesel separators (lower left corner and the other one middle and a bit left). Main engines are drawn in to the right, and there's also the smaller emergency diesel generator drawn into this picture. All the white lines are some of the pipes and valves in the fuel system, but there are a lot of minor connections not visible here.
Large diesel engines needs a bit of cooling down at times. This is the main system for the diesel engines. There is a high temp cooling circuit for the top covers cooling, and a low temperature cooling circuit for more or less the rest of the engine. The heat taken away from the main engines are used to heat up other components in need of heat, and is also used to make fresh drinking water out of sea water through a couple of evaporators.
And here's the rest of the fresh water cooling system, all the auxiliary units in need of cooling. There's a few of them, as you will notice.
Main lubrication picture. You would not get very far if this system started to fail.
What exactly does DP mean?
DP, or Dynamic Positioning operations are what we're doing during our daily work. This simply means that the vessel can be set to one specific position with the bow heading in any preferred direction and stay at that exact point for as long as it takes to get a specific job done. Sometimes it means a few minutes, other times it will mean several weeks or even months. The ship can also be moved in any direction and at any speed (inside limits of course), with the bow heading wherever, only by pressing the right buttons on the DP operation station up on the bridge. This is of course another big computer, or in fact three computers doing the same job. There are two DP computers on the main bridge, and one on the emergency bridge meaning we can still be in full operation even if the main bridge has been totally damaged for some reason.
The DP system is given information from multiple sources to know exactly where the vessel is located, and there has to be at least three different navigation sources active where none of them are allowed to be connected to each other in any way either electrically or in other ways. If they are based on satellites they are not to be working towards the same satellites due to redundancy issues if one particular satellite drops dead for some reason. As you might understand there's a lot of international rules and regulations that comes into play for a DP Class 3 system. I am obviously only scratching the surface here, and in addition I am not at all to be counted as any expert on the matters.
We even got a separate underwater positioning system where a retractable transmitter located underneath the vessel sends out signals which is reflected from beacons we sometimes have placed on the sea bed in known positions. This is a quite accurate system based on something that looks like a mirrorball sending out rays of signals in a lot of directions across it's sphere, and picking them up when their echoes return. This will give the computer system information about the ships movement (heave and rolling from waves by the aid of other instruments (MRU's) on board) which is used by the ROV winches to pay in or slack out wire to keep the TMS (ROV docking station which is located deep in the water) completely at ease relative to the seabed. The same goes for the crane which has the same type of heave compensation to be able to keep the hook completely still at a certain level above the seabed. This is of course to ensure no damage to any very expensive equipment down there. This means that no matter how much the vessel is being thrown up and down, hither and dither, the ROV's and the crane hook is not very much affected of that sort of thing. At least not when looking at these items position relative to the earth herself.
DP Class 3, where the real fun begins: The DP Class 3 notation of this vessel means, among a lot of other things, that we got a bunch of extras. I have already mentioned the precautions taken on the bridge with the separate emergency station which is located in a room of it's own. Most of the extras, special requirements, precautions and of course lots of money spent, are to be found deeper down in the engine room area.
First of all we got two physically separated main engine rooms, pump rooms and thruster rooms. On this vessel this means a longitudinal bulkhead stretching almost from bow to stern dividing the vessel below deck into a starboard and a port side. However the front part of the vessel is divided into another two fully separated zones, one in front of the other, where the bow thrusters and the swing-up azimuth are to be found among some other equipment. Both bow thrusters are in separate zones to make sure any fault on one of them can not affect the operation of the other unit.
The two sides of the main engine room areas are divided by water- and fireproof bulkheads with fire- and waterproof doors installed. If one of the sides for some reason becomes totally useless, there is a requirement that the vessel should still have adequate station keeping abilities. In plain words this would mean that if one side of the engine areas burns out (knocking heavily on wood...), the idea is we should still be able to keep our position and continuing working doing whatever we did before the event.
This is of course not a very likely scenario for the work we are doing these days which is just simply placing of seismic nodes at the seabed, which would of course easily be aborted if something happened. However, in a situation when working on equipment fixed to the seabed close to an oil rig or being attached with crane and ROV's to a well head or something extremely important down there, it could actually be a matter of life or death to a lot of people, or the difference between avoiding an environmental disaster or not.
In short this means we got two more or less exactly mirrored engine rooms all the way from bow to stern, meaning we got two of every single piece of kit and equipment. Or, that's not exactly the truth either, because some bright brains also figured out 20 years ago that if the shit really hits the fan at some point leaving us with only one engine room, what then if a simple cooling pump or whichever component on the still working side started to fail? Oh yes... so not only do we have double up of everything due to having two similar engine rooms, but in addition we are also set-up with a double up of all the important stuff on each side of the vessel as well. So whatever you'll find in any other conventional vessel, we got four of the same thing. And we are not exactly badly equipped from the beginning. It's called redundancy... or overkill as some would probably silently think for themselves. I call it peace of mind, and a hell of a lot of extra work when it comes to maintenance, obviously.
Because that's my teams main job, to keep all of these bits and bobs maintained and in a good working condition at all times.
It's nothing special, just a tiny little but quite good example of a double setup of the fresh water cooling pumps for the aft azimuths on port side of the vessel. One of the pumps will be defined as the "Duty" pump, and the other will then be the "Stand-by" pump. We can change the sequence for any pair of pumps on board by a press of a button in the engine control room.
The lower pipe is the suction pipe going into the pumps, being split to feed both pumps from one main pipe. There will always be water on the suction side of both pumps as a non return valve is mounted just in front of the intake of each pump. Same thing on the pressure side (upper pipe). Separate outlets from the pumps going into the same pipe feeding the cooler further down the line. Both pumps got a pressure transmitter on the pressure side which is constantly sending a signal to the computers. If the pressure on the main line is getting too low, the stand-by pump will start and the pressure will normally rise (at least as long as there's not a block in the suction pipe or something like that...). There are a lot of similar constructions around this vessel, working the same way.
Maintenance, and how to keep track:
To make sure everything is well maintained at all times, we got a computer based maintenance system. Every single routine job has been registered and put into the system with the right periodic notation to make sure it shows up on the work list in due time. When the job has been done a short or longer service report has to be made for the various jobs. Most of the jobs are only small check jobs and light maintenance, but some are bigger jobs which usually is a bit harder to actually get done as long as the vessel is working in DP operations, simply because of the fact that if you isolate some equipment to do work on it you have taken away the safety of the double-up (redundancy) idea. Still, depending on which DP class we are working in at any time, we might be able to get the job done anyway. After all we are not working in DP class 3 all the time. DP class 1 and 2 are lighter versions of DP class 3, requiring less redundancy and better chances for the engine dept. to get their maintenance done in time. In other words we quite like DP1 and 2 a lot better than DP3.
Anyway the list of overdue jobs will sometimes grow to be quite long, which in turn might lead to a needed stop for maintenance. These tends to be a stop over maybe a couple of days or so to get at least most of the overdue jobs done in a good way. Most of the time for normal maintenance we will discuss the best time to get the job done with the client, making it as smooth as practically possible. There will be times when both parties need to get ashore and stay alongside for a couple of days for several reasons.
Usually this works well enough, but we might be in need of highly specialized on-shore facilities with special tools to get some of the more special and heavy jobs done, which is not the easiest thing to find in every corner of the world.
On a ship like this, which is designed to be sent into operations world wide, we need to be quite well stocked-up on spare parts and tools of more or less any thinkable and sometimes unthinkable sorts.
It is a bit scary sometimes to think about the fact that for instance a small £30,- bearing missing from the stock might stop a million dollars a day operation just like that. In short you have to make sure that exact bearing is on board, and just as important you have to make sure both you and any other engineer can find it the day you need it. Every single spare part on board the vessel is of course also registered into the same computer system which takes care of the job list and a lot of other functions I am not going to talk about here and now. The name and type of spare part will be registered along with the location of where it is to be found, how many items we got of the thing and when it was put there. All spare parts got a sticker attached to it, making it easy to remember to register all spares used for any maintenance job to make sure the spares has been taken out of the system to keep count of them.
Different types of maintenance: One thing is the planned maintenance and all the jobs falling under that umbrella. Those are typically oil changes, checking vibrations in a pump, check for leaks, change of bearings, send oil samples for laboratory check and so on. Light maintenance, usually weekly checks or at least calendar based.
Some heavier maintenance is hour based, making it important to keep track of the running hours of all the machines and electric motors on board. This will involve typically 15000 hrs. or 30000 hrs maintenance on main engines, bearing changes on big or small electric motors, check of valves facing directly to sea and a lot of other things.
Another and completely different thing would be the unplanned but oh so necessary maintenance. You know the sorts for sure as it usually calls for attention with a big bang of some sort. There are different reasons for breakdowns, as any car or bicycle owner among you would know well enough. Sometimes it happens due to badly maintained equipment, other times it might happen to a brand new unit due to poor quality on internal parts, other times it even happens due to wrongly assembled machinery shortly after maintenance has been done, or even on brand new equipment for no obvious reason at all. The more money you payed the more often it breaks down, or so it seems at times anyway.
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That's about how far I'm going to take this for now. I'm coming back with some more specific engine maintenance related stuff, a few words about ROV related operations (the very little I know about it...) and also a few thoughts about how I look at the shipping future and what might be in there of things to think about.
But for now, this hopefully will keep you busy reading and thinking for a little while.
And as always, please feel free to comment or ask any question and I'll see if I might be able to give you an answer you can hopefully live with.
