Elevators and Cranes in Ships (Coursework Sample)

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Elevators and Cranes in Ships
Introduction
Elevators and cranes are essential components on board the ship. Most countries such as the USA have placed regulations that ship engineers should adhere to. For example, engineers should install the ship with the recommended machines and systems according to the safety standards outlined or provided by the government. It is important to note that the ship requires multiple operating systems in order to sail accordingly. Examples include lighting systems, battery systems, steering systems, cranes and elevator systems. Therefore, crew members on board the ship need to have adequate training in operating different machines and systems on board. Crew members also need training on handling passengers on board. The senior ETO is responsible for facilitating training programs for the crew members. In this paper I will give a report on the elevator and cranes systems in ship. I will focus on the types of elevators on board, where they are used and their maintenance practices. In addition, i will discuss the types of cranes used on ship ad their maintenance practices.
ELEVATOR SYSTEMS
Purpose of elevators
Usually, elevator systems are mainly used to move people from one floor to another within the ship (Emmitt 503).Passenger elevators are usually designed in such a way that they can carry a specific number of people. They also have interlocks that only open when the elevator has reached its landing point. This means that, the design of these elevators ensures passenger safety. Some elevators are purposely used for unloading heavy cargo and other materials. Such elevators are designed in such a way that they can handle or manage the heavy weight of the cargo. An example of an elevator used to offload heavy cargo is the L-bucket elevator. All of these elevators in the ship obtain their power from the electric motors (Emmitt 503).
Diagram of a ship elevator system
Fig 1: Diagram of a ship elevator system (Burns, 2001)
Types of elevator systems
There are several types of elevators used in board the ship.The most common ones include bucket elevators, chain elevators and pneumatic elevators.Bucket elevators are used to handle heavy materials such the grain. The lift height and the capacity of this type of elevator vary according to the type of vessel in which it’s being used. In this regard, it is important to match the type of elevator with the type of task or with the kind of material intended to carry(Clarke 868).
Pneumatic elevators are common at the docks. They are usually used to unload ocean-going ships to shore installations (Clarke 868). Pneumatic elevators require a high capacity of carrying cargo in order to unload bulk-cargo ships which carry heavy loads up to 60, 000 tons. These types of elevators could be used together with the L-bucket elevators in cleaning the bottom of hold. Chain elevators, also used on ship, are usually used to carry grains. The chain elevator works under the en masse principle. The principle requires that, once the cargo is placed on the unit, it fills the elevator system from its inlet to its outlet. This operation becomes successful either vertically or horizontally (Clarke 868).
Safety considerations and maintenance
Safety consideration is important in the elevator system. This means that elevator designers must ensure the safety of passengers and materials while inside the elevator. Various international safety standards are used to design shipboard elevators. The most common on is International Organization for Standardization (ISO) lifts on ships (Strakosch 220). Others include ASME A17.1/B44 safety code for elevators systems and International Convention for Safety of Life as Sea (SOLAS). We know that corrosion incidences are common in the ship. In this regard, elevator designers must ensure that the system is water-proof in order to prevent corrosion. In addition, both the elevator and the elevator control system should be designed in a manner that they can still operate when the ship yaws or rolls.
The floor of the elevator should not be slippery to avoid passenger falling or materials sliding. The most important thing is that, all the elevators and their control system need to have abilities to withstand forces exerted as the ship is in motion (Strakosch 220). It is important to note that cargo elevators are drum machines which are usually designed to carry the entire load weight during the operations of loading and unloading (Strakosch 221).
Training considersations
Considering the nature of the elevator systemson board, it is imporatnt for the elevator operators to have training on how to operate them. The senior ETO should facilitate the tarinning program which may be done on board. Training on the handlingof materials in the elevator is important to avoid damage. In addition, elevator operators should have the skills to operate the elevators in order to avoid injuries system breakdown.
Movement control through Sensors and actuators
To control the movement of the elevators, there are hydraulic buffers which are installed at the bottom to safely stop loaded and fast moving elevators. There are also breaking arms which are connected with a cable to the governor unit. They coordinate with the guide rails to stop fast moving elevators especially when they are loaded with either materials or passengers. These sensors also protect the elevator from overloading. In addition, there are door interlocks fixed on the elevators in order to prevent movement of material until all doors are closed. The interlocks also prevent the landing doors from opening until the elevator stops at the landing point (Strakosch 221).
CRANES
Types of cranes
Just like elevators, cranes are used to handle cargo on the ship. They are various types of cranes on board the ship. Usually, they are classified according to the type of work they perform.Major types include Cargo winches or Derricks, deck cranes Jib Cranes and gantry cranes (Shama 11). In most modern ships, the deck cranes reduce manpower requirement in handling the cargo. A heavy-lift derrick crane may be installed or fitted for the same purpose.
How a crane system works
To access the cargo hold in the deck cranes, the crane operator may use the openings found in the deck called hatches. When the ship is already sailing, the hatches are closed by the hatch covers.Ship cranes include electrical control systems such as switches, hydraulic control systems such as hydraulic pumps and motors and mechanical components such as brakes. All of these systems ensure safety when carrying the cargo (Shama 11).
Diagram of crane system
Fig 2: Example of a crane system(Thoresen, 2003).
Limitations of Cranes
The crane has various limitations as an unloading system. For example a lot of time is spent to transport the material to the quay. In addition, unloading materials using the crane exposes them to the atmosphere as it is an open unloading system. The crane system is not suitable for transporting products made of powder (Shama 13).
Crane maintenance practices
Cranes and elevator systems on board the ship require maintenance practices. For instance, in case of cargo gears, maintenance includes oiling and regular greasing (Verschoof 20).It is also important to inspect the wire ropes and sheaves. Gantries must free at all time because they could fall on the deck and cause injuries to anybody passing below. The hydraulic units should be checked regularly in case of any leakages. In case of the elevator system, the interlocks should be fixed to prevent falling of materials from the elevator car. In addition, all control system such as the hydraulic and breaking system should be double checked before any material is elevated from one floor to another. This is done to avoid accident...