...nt ship, designed for the specific purpose of transporting liquid cargoes in bulk. Tankers generally have their machinery spaces aft at the stern, or back end, of the ship. Forard of this are the cargo tanks. These are numbered from forard to aft, ith the number one tank being the furthest forard. Each tank is further divided longitudinally from fore to aft by one or more oil-tight bulkheads, so the vessel may have an arrangement such as port number one tank, starboard number one tank, and perhaps centre number one tank. This improves stability by preventing liquid sloshing from side to side hen the vessel rolls. One or more pump rooms ould be provided, and these are used for discharging cargo. Tanks can be fitted ith heating systems to allo heating of heavy oils to enable them to flo, steam smothering systems to put out a fire in the tank and vents to allo gas to escape. These vents ould be fitted ith flame arrestors on vessels here light oil cargoes ere intended to be carried. At around the mid point of the ship ould be the main superstructure, containing accommodation for deck officers, the navigation bridge and the radio room. The accommodation for the engineers ould be at the stern, above the engine room.During the Second orld ar, tankers ere particularly valuable targets. hilst the loss of general cargo vessels caused much concern, it as the loss of tankers that caused the most anxiety as they ere being lost at a much greater rate. As the highest-value ships in a convoy, tankers ere normally placed in the inner columns. This shielded them somehat from attack, although the losses continued to be a problem until the Battle of the Atlantic as finally decided. Tankers are difficult ships to sink. They are ell subdivided in to atertight compartments, and are designed to carry a liquid of approximately the same density as ater. If you put a hole in the starboard right side of the tanker, the oil ill run out and the vessel ill list lean to port the left hilst rising slightly out of the ater as the eight of cargo is reduced. The vessel ill only sink if structural failure occurs. The main danger faced by cres of tankers as fire. hilst crude oil is difficult to set alight it is thick, often does not flo unless it is heated, and if a lighted match is dropped in to it the match ill simply go out, refined products such as petrol and aviation fuel can be very flammable.2. Passenger Liner A passenger liner may be defined as A merchant vessel designed for the main purpose of carrying passengers. Passenger liners are usually fast ships, ith a speed beteen 25 and 30 knots. Passenger liners ere very different ships from the cruise liners of today. Their main purpose as to transport people beteen destinations, in much the same ay as the airliner does today, rather than to provide a pleasant holiday experience. In the same manner as a modern airliner, passengers ere split in to a number of classes. The first class passengers travelled in luxury, hilst the loest class passengers ere packed in as densely as possible. The most important aspect of a passenger liner as its speed, ith faster ships attracting more passengers and higher prices. This as because passengers simply anted to get to their destination rather than enjoy the process of travelling. This obsession ith speed fuelled great rivalry beteen the great liner companies, particularly on the prestigious North Atlantic route here the Blue Riband trophy as handed to the fastest ship to make the crossing. The speed of this ships as a great advantage during the Second orld ar, as it made them almost invulnerable to submarine attack. As they could easily outpace even a surfaced submarine, they could be torpedoed only if the ship accidentally sailed in to range of the submarine. As the torpedo range as limited, the ocean very big and submarines reasonably fe in number, passenger liners ere unlikely to be attacked even if unescorted. Passenger liners ere essential to moving the large quantities of troops needed around the orld. One of the largest ships as the RMS Queen Mary, hich carried up to 15,000 troops per trip, and their presence simplified the vast logistical problem facing the Allies. Germany and Italy had less need for such vessels, particularly as their sea lanes ere generally less secure than the Allies and the fighting as generally reachable by land, although if they had managed to take Europe as planned they ould have been essential to any next steps and their lack as keenly felt in the Noregian campaign. Japans problems ere more complex. Passenger liners ould have made their expansion much easier, hoever once they began retreating their shipping as not safe and such ships ould not have helped. Passenger liners ere very vulnerable to surface and air attack and, in areas here such threats ere present, needed to be heavily escorted. Submarines, hoever, posed little threat and liners could operate in aters knon to contain submarines provided they had a choice of routes i.e. ere not constrained to going through a particular area.3. Bulk carrier A bulk carrier may be defined as A merchant vessel designed for the primary purpose of carrying solid cargo in bulk. These vessels ere developed from a need to be able to handle certain types of cargo more efficiently then could be done in standard general cargo vessels. This included goods such as grain hich could be piped in and out of holds quickly, coal and iron ore hich ere easier to handle in bulk rather than bagged on pallets. Bulk carriers could be extremely vulnerable to submarine attack if they carried very dense cargoes, such as iron ore, scrap metal etc. Such dense cargoes mean that holds contain a lot of empty space to provide the necessary buoyancy. If the ship is torpedoed, ater rushes in to the empty space, rapidly destroying the ships reserve of buoyancy and often causing structural failure. It as not unusual for scrap metal or iron ore carriers to sink ithin to minutes of being torpedoed, and they ere not popular assignments for merchant cres because of this.4. General Cargo VesselA general cargo vessel may be defined as A merchant vessel designed for the primary purpose of carrying break-bulk dry cargo. These ships generally had a central engine room, ith cargo holds forard and aft of this. The accommodation and navigating bridge as located above the engine room. Accommodation could also be provided at the stern of the vessel in the poop and at the bos in the forecastle. These ships generally had their on cargo-handling equipment booms so that they could handle cargo ithout having to rely on shore facilities. During the Second orld ar, guns ere fitted for defensive purposes. The speed of these v...
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