(Saturday, March 19th, 2016)
I took a tour of the engine room today with our Chief Engineer. The Chief Engineer was very patient with me and answered all my questions. I put on gloves and ear protection. Ear protection for the obvious, gloves in case I accidentally touched something hot.
I asked him if he were second in command to the Captain. It’s not that direct. The engineering officers are separate from the line officers (Chief Mate, 2nd Mate, …), so, no, he is not a part of the command chain. However, the Chief Engineer is considered the second most important officer on board, after the Captain, and so gets that kind of respect, gets a sweet cabin, that sort of thing. Later, I learned some more about freighter management, but that’s for a different post.
I was not allowed to take pictures – company rules, rats. I am writing this as soon as we’ve finished the tour, so that the least amount of brain cells die in the interim.
The “engine room” is really an entire area of the ship, with about 20 rooms, three or four stories. It is totally industrial, mostly cream-colored paint on metal with various things painted yellow and red – there isn’t any fake wood on the doors or anything like that. There is more room to move around than I would have thought, but it is pretty well filled with active equipment. It is very noisy throughout, with the exception of a control room that is somewhat isolated. It is also hot throughout, and it is still chilly outside. I was warned not to visit the engine room while in Singapore, and now I appreciate that advice.
The first area we stepped into contained the generators. There are three generators. Each of the generators has several cylinders and is fueled by fuel oil. Each is about 6 feet tall and maybe 10 or 15 feet long. One generator is sufficient to power the ship, two are required when the cranes are in use, so there are three in order to have a backup. At the time of my visit, at sea, daytime, nothing special going on, one generator was at about half capacity, the others off. The Chief Engineer said that when all cranes were active two generators would be at almost peak capacity. I forget what the generator capacities are – 1000 something (but I forget the units, so the number is not that useful).
Near the generators are several large electric motors connected to ductwork. They are used to provide pressurized air. I assumed that this is for starting the engine, but I am not sure. I do not think they were operating when we walked by.
Above us was exhaust ducting. The ducts are about 12 feet in diameter, and in one section were about 20 feet in diameter, silvery, and you could feel the heat coming off them as you walked under them.
In the next room are two boilers. One was conventional, about like what you would see in a medium apartment building except more stoutly attached to the floor and to piping, heated with burners underneath, running on fuel oil. This is the boiler that is used when the engine is not running, when we are in port. The other boiler’s shape I couldn’t really discern, as it disappeared behind another wall. Into the center of that boiler ran some auxiliary ducting from the exhaust ducting. That boiler is heated with engine exhaust only, and is the boiler in use when the engine is running.
Following the exhaust ducting along, we came to what the Chief Engineer called a turbine, what I would call a turbocharger. It was a hint as to the size of the main engine. The turbocharger was a cylinder whose diameter was about 6 feet (at least as tall as me, hard to remember exactly), and whose width (or length, if you please) was about 3 or 4 feet. I could see where exhaust gas went into and out of the turbo, with maybe 3 foot diameter ducting, and pressurized air left the turbo in a steel pipe, headed downstairs.
We then went down one story, to the top of the main engine. Up in this area we also went by another container, about the same size as the boilers, and also fed by some exhaust ducting. It is a water purification system. The ship takes in sea water, applies a vacuum to it so that its boiling point is coincidentally the temperature of the engine exhaust gases (about 85C), and then heats it with exhaust gas. This evaporates the salt, and does other things. The result is distillate – pure fresh water. This is water we use as potable water on board, but we don’t recommend it for drinking. We drink bottled water. But in a pinch we could drink it, there’s no health hazard, it’s just not great. Every so often, if the engine has been off for a while, like a long stay in port, we have to buy some water. And we take on bottled water at each port. But the water we shower with started out as sea water that we purified while underway.
The main engine is 7 cylinders. It is a two-stroke turbo diesel, where “diesel” in this case refers to the fact that it is a compression ignition engine rather than a spark ignition engine, not the fuel type. It is a bit amusing to me that the tachometers for this engine are not representing hundreds or thousands. When the meter says 90, that means that the engine is doing 90 RPM, period. For the past couple of days we’ve been running at about 90 RPM, which translates to a ship speed of about 17 knots.
This engine is considered a low speed engine (no kidding!), and there are medium speed engines (up to 400 or 500 RPM) and high speed engines (up to 1200+ RPM). There are tradeoffs. In general the advantages of our engine are these: An ability to direct-connect to the propeller. Simple, direct. An ability to use extremely low grades (think cheaper) of fuel. Disadvantages: This engine is very tall, which can be in the way for some other ship configurations. This engine must be placed directly in front of the propeller (the other engines use reduction gears so can be offset), which also limits ship architecture. This engine is heavier per power output than others. But it is economical in both “mileage” and type of fuel usable, which are significant advantages.
The main engine is about three stories tall, with metal stairways going this way and that to access different areas. Each cylinder has a bore and stroke of about 3 x 10 feet. Each cylinder head has two injectors feeding it. Each injector is roughly a 6 inch by 2 foot cylinder, and the fuel lines are 2 inch pipe. The injectors have modes (and I think different nozzles but I am not sure) that can be used so that the engines run efficiently at a set lower speed and a set higher speed. The crankcase is the size of a room. Each cylinder has an access door so that maintenance can be done on the lower end, the crankshaft and rod. Each of those 7 doors looks like an ordinary ship’s door that a person could walk through, except for the type of fittings keeping it closed.
We went to another room, and the Chief Engineer lifted a small (meaning, humans can lift it) hatch cover, and we looked down at the spinning mainshaft, leading away from the engine, and connected to the propeller. The shaft was about 2 feet in diameter. We went to another room, and up some stairs, where there were two electric pumps keeping hydraulics pumped, and there were lines feeding the steering gear. The steering gear looks a bit like a motor, and is maybe 10 feet in diameter and 5 or so feet tall. Below it is the rudder.
There were rooms devoted to maintenance, looking like small machine shops, active. We didn’t spend a lot of time there, we would have been an annoyance to people trying to work.
We went to the control center, a noise-protected control room. It looked a lot like some small industrial control rooms that I’ve been in. There were a couple of engine management screens, control panels for the three generators, and a control panel each for each boiler and the fresh water system. There was also a control screen showing the various fuel tanks and the fuel sanitation system, and the pumping systems between them.
There are many fuel tanks throughout the bottom of the ship. There are a couple of special tanks into which the others feed. The first of these special tanks is one in which about-to-be-used fuel sits for a while, allowing sediment to get to the bottom. From this tank fuel is then pumped into another special tank in which filters of many types remove impurities. From this tank fuel heads to smaller, pressurized tanks feeding the engine.
My description above applies to fuel oil, the primary fuel. But there are at least two other similar but smaller tank systems. One for diesel, and one for lube oil, the oil that goes in the crankcase and eventually throughout the engine. Remember that our engine is a two-stroke, which means a constant-loss oil system for lube oil, at least for a part of it.
I think I wrote about this earlier, but a recap here is apt. We have 2600 tons of fuel oil and 400 tons of diesel on board. We switch to diesel in environmental areas, such as US, Europe, and soon to be Chinese ports. Everywhere else we use fuel oil. Diesel is more expensive. We burn about 30-35 tons a day at sea.
I learned that the engine could be controlled from the bridge (the usual case) or from the engine control room, in an emergency. There are several parameters being measured that can raise alarms in the control room, on the bridge, and in the Captain’s and Chief Engineer’s cabins, and can automatically reduce engine speed or stop the engine if not acknowledged fast enough.
Major engine maintenance occurs on the basis of hours of operation, unless there is an emergency problem like a part failure. Generally, the exhaust valves need to be resurfaced at 16,000 hours, and since so many other items can get accessed if the engine is opened enough to service exhaust valves, many other parts, intake valves, pistons, piston rings, crank bearings, piston liners, all that sort, are serviced as well. We average about 500 hours a month of engine time, so it works out to major maintenance approximately once every 3 years, given the normal (almost constant except at port) usage.
Tour’s over! Up from the depths, into a cool and (relatively) quiet hallway on the poop deck. Quite fun.