Running parking space - Pure Car Carrier

Red circles on the calendar A calendar on the wall shakes slightly as the ship moves. "Marine Highway", with Mr. Kawasaki (Kawasaki-san) on board, will tomorrow finally arrive at Jacksonville Port, the first port on the U. S. East Coast. The 25 days since the ship left Nagoya Port are all circled in red on the slightly shaking calendar on the wall. Each red mark is full of memories. Kawasaki-san has had many valuable experiences on board "Marine Highway" that he would never have had on land. For example, they include ‘ shortcuts at sea’, ‘ all about ships’ tonnage’ and so on. As the entire journey flashed before his eyes, Kawasaki-san expresses his true feelings: "I wish I could stay on board much longer." But he cannot always do what he desires. In Tokyo, work has piled up on his desk. In addition, he cannot cause any more inconvenience to the crew, who have kindly guided him in many ways, in spite of his poor knowledge of ships. Kawasaki-san spent the full morning cleaning his room and finishing packing for his disembarkation.

-------(1)Stowage Plan------

A car deck full of cars.

In the afternoon, the captain of the ship told him, "I suggest you go with the chief officer as he goes and checks the holds prior to unloading. You may hear from him a lot of interesting stories, because he was in charge of stowage plans at ‘ Technical Section of Car Carrier Group’ for more than 60 PCCs (Pure Car Carriers) that our company operates before he came on board this ship." In response to his suggestion, Kawasaki-san followed the chief officer down many steps of the vertical ladder to the lowest car deck. The chief officer grinned as he asked Kawasaki-san,

"How tall are you?" "I am 175 cm tall." In that case you won’ t bump your head against the ceiling even if you run as fast as you can. This car deck is 185 cm high. The deck of an old ship used to be 165 cm or 170 cm. And so tall crew members had to stoop their heads as they walked to avoid hitting the ceiling. For some years now, however, we have been exporting more SUVs with a vehicle height of about 170 cm. If we are to allow a certain clearance (8 cm - 10 cm), we cannot store cars on a deck with a height of 170 cm. So, Pure Car Carriers have decks with a minimum height of 185 cm these days."

Although Kawasaki-san parks his car in a city parking lot, he has never seen cars loaded so orderly and without any waste of space. He asked the chief officer a few questions.

"How many cars did you load? Have you ever been unable to load the planned number of cars?" "The loading capacity of this ship is 6,000 RT. The unit RT indicates the loadable number of a passenger model car with length of 4.125 m and width of 1.55 m. It means that the ship can load 6, 000 units of RT passenger cars with a gap of 30 cm in front and behind and with 10 cm on both sides. In other words, the useful car loadable area of this ship is (4.125+0.3) x(1.55+0.1)x6,000 = 43,800 m2, or we load passenger cars fully on a parking lot that is equal to six official soccer grounds (105 m long x 68 m wide; area: 7,140 m2). But the size of a passenger car is generally larger now. If it is 4.5 m long and 1.7 m wide on an average, the area per unit is about 1.25 RT (4.5x1.74/4.15x1.55). If this is the case, the ship can load 4,800 units of passenger cars. For this voyage, we are loading a large construction machine such as an excavator and lift up two deck panels of the seventh deck and so we are actually loading 4,752 units. This stowage plan has been made by our Tokyo head office. I was engaged in this work for three years. Before Personal Computers became popular, we discussed how many cars we could load by putting a 1/100 "paper pattern" of the size of each passenger car on the 1/100 drawing by deck. But we developed SPS (Stowage Planning System), under which we can now make a stowage plan quickly on the screen of a Personal Computer after we input a drawing of each ship and a model of loading vehicles to a computer. This ship "Marine Highway" has 12 decks of cargo holds, which are divided into 41 compartments. Under the actual stowage plan, we are supposed to load cars that have different sizes with gaps of 30 cm in front and behind and with 10 cm on both sides, and efficiently without any waste of space; but if each compartment is one car short of that planned at the site, we are 41 cars short in total. If we store the cargo loosely to prevent accidents such as cargo collision, we may lose useful space and it may have an impact on our profits."

Kawasaki-san noticed that there was still space for ten units around the stern ramp, but he refrained from asking that question, because he understood that ten compartments loaded ten more cars than planned.

Stowage Plan (12th Deck)

PCTC can load any vehicle

Kawasaki-san followed the chief officer, climbed up the vertical ladder from the lowest deck to the sixth deck. The entrance to this vertical ladder is fitted with a hatch. This hatch is closed during voyages so that in case of fire, no smoke or fire enters other compartments. In addition, the 41 compartments of the car deck are divided by five partitions for fire prevention. If a fire should start within one partition area, it is arranged so that the fire does not spread to other partitioned areas.

When Kawasaki-san arrived at the stern ramp of the sixth deck, he saw a large vehicle. We can often see such large vehicles at construction sites.

"Chief Officer, you load such a large vehicle. I thought we would load only passenger cars." "This is called an excavator. It is a heavy vehicle with a height of 399 cm and a weight of 35 tons. The sixth deck of our ship is usually only 240 cm high and so we raised the two panels of the seventh deck above, adjusted the height of that portion to 440 cm and then loaded it. The seventh deck is originally 210 cm high and we load passenger cars with a height of up to 200 cm. The reason why we lifted up only two panels is because we still wanted to make efficient use of the remaining space of the seventh. Of course, we lost the space of 40 cars on the seventh deck when we raised the two panels but it cannot be helped." "If we load such a heavy vehicle, I am afraid that the caterpillar tracks may damage the deck. It may move around in rough seas. The captain told me the other day about the stability of a ship. I am afraid that it may be reduced."

The chief officer pointed to an old hawser put at the entrance of the stern ramp and said.

"When we load such a heavy vehicle, we slowly load it while we put hawsers and wooden plates under the caterpillar tracks in order to prevent them from damaging the surface of the deck. In addition, we use anchor points of SWL (Safety Working Load: a unit of strength for safe use) 1.5 tons for a large vehicle and use enough number of them to meet the weight of the vehicle. We usually load a large vehicle on the entrance deck (a deck for which a stern ramp can be used) that is designed to have more strength than that of the other decks for ordinary passenger cars so that the center of gravity of the ship may not be high. A recently built PCC that can load a large vehicle is also called a PCTC (an abbreviation of Pure Car/Truck Carrier). A PCTC can load bulldozers and excavators as well as trucks and buses." (Note: Some PCTC of our company load construction machines on part of the above deck. In this case, we calculate the stability of the ship and take full measures including adjustment of ballast and additional fuel supply to lower the center of gravity of the ship so that we can carry out safe navigation.) Didn’ t you notice a number when you went aboard the ship from the stern ramp in Nagoya?

As I recall, I saw some tons of SWL and H = 240, 265 and 440. I did not know what they mean. The first one, SWL 100 tons, means that this stern ramp can accept a vehicle with a weight of up to 100 tons. The second one means that the sixth deck can be 265 cm and 440 cm high if we raise the seventh deck.

Everything was new to Kawasaki-san. He felt the chief officer’ s explanation was breathtaking.

------(2)Damage-free unloading work -----

Meeting before unloading

The chief officer was just going to have a meeting before unloading with the crew at the office behind the bridge and Kawasaki-san decided to join the meeting. The chief officer explained the care and attention needed to avoid damage at unloading including the prepositioning locations of the cargos to be unloaded at Jacksonville Port, precautions not to mix the cargos with others (We avoid mistakes in separating the cargos from that to be unloaded at other ports by using a tape called separation tape.), the travel routes and the ramp ways to use. After the meeting, Kawasaki-san asked the chief officer,

"When you unload the cargo, you don’ t only use the stern ramp that we viewed last time, do you?" "If we can use two places of the stern ramp and the side ramp, we can shorten the unloading time that much. In addition, for a pure car carrier, the allowable angle of the ramp way (angle between the ramp and the land surface) is to be at least 1.5 degrees and no more than 13 degrees. At a port with a wider tide range like Jacksonville, even if we set a ramp way for the sixth deck at low tide, we may cause damage to unloading cars (by nose or tail hit) because the angle increases at high tide. And so we have to change the ramp way for the fifth deck at the right moment. My calculation shows that in four hours the tide becomes high and tide difference becomes 92 cm. If we unload 280 units (about 400 tons) per hour, we can unload 1,600 tons in four hours. It means that the body of the ship will float 1.25 m high from the pier (1,600 tons = 33 cm) in four hours after unloading started. Unloading of 1,600 car units means that we unload 2,240 tons (assuming 1.4 tons/unit) from the ship and the draft of the ship reduces by 47 cm. Combined with the high tide, the height from the sixth deck to the pier becomes great and so we have to change the ramp way to the fifth deck four hours after unloading started."    "Is that so? You must consider many factors. I saw the hold last time and I was very much surprised to know that there was not any damage to cars though as many as 4,800 car units were loaded like sardines." "You are right, Kawasaki-san. Our mission is to unload the cars in the same condition as they are loaded. For this reason, we are never supposed to cause any damage to cars, to unload cars at a wrong place or leave some cars unloaded. Therefore, I let the crew know all the care and attention item-by-item before calling the port in order to prepare for safe cargo handling. After we arrive at Jacksonville Port, we will have a meeting with the ground staff members."    "With the ground staff members, too?" "Yes, that’s right. It is a big mistake if you imagine that the ground staff members are familiar with cargo handling because similar ships come very often. Even if the ship is the same, the place where the crew lifts up a panel is different from the previous voyage, the prepositioning locations for Jacksonville Port are different by voyage and so the travel routes are naturally different. Both ship and ground staff members must make the utmost effort together to prevent any damage from occurring while we put cone caps or put up "No Trespassing" barriers known as barrier curtains so that a tall vehicle such as a van may not enter a low deck and collide with it when it runs around the travel route, and its roof may not be damaged." "If the crew properly arranges the damage prevention materials, it will help the work of safe and efficient cargo handling."

Short berthing hours

"That’ s right. As you can see, the ship’ s crew are put to watch around the ramp way. They check passing cars to see if they are being unloaded without any damage. They also check the angle of the ramp, the rubber fenders placed where the pier and the ramp make contact so that passenger cars do not bump their front ends, and the berthing ropes. Recently, they have been very strict in checking for suspicious persons entering the ship as a countermeasure for terrorism." "Are all the crew in the cargo holds?"    "That’ s right. Here in Jacksonville, we handle cargo under the four-group system. Other crewmembers watch the cars so that the cars do not collide with each other when the first vehicles are taken out of the prepositioning location, and also put cone caps on the travel routes and remove the claspers spread on the deck after they are dismounted and removed from the cars. All the members put their full energy and attention into the cargo handling work. This time we are unloading 1,600 car units and so we can finish the work in six hours at most." "Then the crew has to work all the time while the ship is sailing and also while the ship is at berth. This may be their job but it is a tough job, isn’ t it? They cannot take a rest without anxiety. Until I heard you, I imagined that sailors could go to various countries, enjoy sightseeing and shopping while the ship is at anchor. But reality is very tough, isn’ t it?"    "That’ s right. Recently almost all the ships have been specialized. Even a large containership finishes loading and unloading about 1,000 containers in only eight hours while the ship uses four cranes. Even a car carrier like this ship once unloaded the cargo full of cars only for eight hours. This ship is not a good one for sailors but for shopping at foreign countries the crew now can ask a food supply shop by e-mail. The greatest entertainment for the crew is for them to go ashore in turn when the ship happens to stay at berth overnight."

When Kawasaki-san heard that story, he felt a little relieved. Kawasaki-san will get off the ship tomorrow when the ship arrives at port. He has decided to leave the ship after he has a good look at the scene of unloading with the permission of the captain. The unloading scene seems to be a battleground.

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