MEOclassIIexamnotes

1. High cost: Manganese bronze is a costly alloy, making it less economical for large propellers. 2. Low strength-to-weight ratio: Compared to other propeller materials like nickel-aluminum bronze or stainless steel, manganese bronze has a lower strength-to-weight ratio. 3. Susceptible to corrosion: Manganese bronze can corrode in seawater, especially when exposed to high velocities and turbulence. 4. Poor cavitation resistance: Manganese bronze is more prone to cavitation damage than other materials. 5. Difficult to cast and machine: Manganese bronze is challenging to cast and machine, making it less desirable for complex propeller geometries. 6. Limited weldability: Manganese bronze has poor weldability, making repairs and modifications difficult. Nickel-aluminum bronze or stainless steel are commonly used for propellers due to their: - High strength and durability - Excellent corrosion resistance - Good cavitation resistance - Ease of casting and machining - Weldability

 The nomenclature for bearings, such as the "NU 318" bearing, follows a standardized system that provides information about the bearing's type, dimensions, and other characteristics. Here's a breakdown of the "NU 318" bearing nomenclature: 1. **NU**: This indicates the type of bearing.    - **NU** stands for a cylindrical roller bearing with two flanges on the outer ring and no flanges on the inner ring. This design allows the inner ring to move axially relative to the outer ring, making it suitable for applications where axial displacement needs to be accommodated. 2. **3**: This digit represents the series of the bearing, which indicates the overall size and load capacity.    - **3** typically refers to a medium series bearing, which is designed to handle moderate loads and speeds. 3. **18**: This number indicates the bore diameter of the bearing.    - The bore diameter is calculated by multiplying the last two digits by 5. In this case, **18 x 5 = 9...

  The speed of the marine engine is controlled by an instrument known as governor, which can be of – hydraulic, electro-hydraulic or electronic governor type. The most famous types of governor used for both main engine and generator engine is the electro-hydraulic type marine governor. It’s because of this little instrument that the engine speed can be smoothly controlled from a remote space (bridge or engine control room). The different components of a governor allows for a steady state speed control, along with achieving the required variation in the load. Following are the important parts of the governor: – Synchronizer knob: This knob is used for controlling the speed of the engine with a single unit (Main engine) and controlling the load for engines with multiple unit (generator) – Speed droop knob: The speed droop knob helps in creating the stability and also divides the load equally among multiple generator engines running parallel – Load limit knob: This knob controls and l...

An insert plate is used to replace any damaged steel plate of ship's hull. The insert plate must have identical characteristics with the original steel plate ( type /grade/thickness etc). The damaged part of the steel plate has to be cropped-out and renewed by welding using the same welding consumables. The minimum consumable grades. All ship's Class Societies consider the above mentioned requirements as permanent repairs for maintaining the ship’s Classification Certificates fully valid. On the contrary, doubler steel plates which are welded on top of a damaged structure plate is considered as temporary repaired with a short limit date until the full permanent repairs are dealt with

For engine seating a plate floor is required every frame  Main engine seatings are in general integral with this double bottom structure.  Inner bottom in way of the engine foundation has a substantially increased thickness.  Often the machinery is built up on seatings forming longitudinal bearers which are supported transversely by tripping brackets in line with the double bottom floors, the longitudinal bearers being in line with the double bottom side girders.  There are transverse plate floors at each frame. The thickness of the engine seating is governed by the power, weight, and length of the unit

A dual class vessel is one which is classed by two Societies between which there is a written agreement regarding sharing of work, reciprocal recognition of surveys carried out by each of the Societies on behalf of the other Society and full exchange of information on the class status and survey reports.  All the ships of "The shipping corportation of India" used to have dual class.  Out of two, one classfication society was "Indian Registrar of shipping".  Indian ships were required to have IRS as its classification society but as IRS was then not a member of IACS, ships were forced to have a second classification society which was member of IACS.  So in this case, these ships would have certificate of class from each classification society.  In 2010 when IRS became the member of IACS, Indian ships were no more required to have Dual class.  More than 50 classification societies. But only 12 are IACS members  A double classed vessel is one which is ...

Both Leak & Structural test  Test head :  The greater of –  Top of the overflow To 2.4m above top of tank   To bulkhead deck    Procedure: Fill tanks by gravity to sea level. A ballast pump can be used if the vessel wishes, but is not recommended. If there are scuppers, then block scuppers as would be required for bunkering operations.  Close sounding pipes tightly if these are at deck level.  Open, or take off, air vent tops.  Top up tank through air vents by fire hose until (assuming stern trim) water level is close to top of aft air vents.  Ensure that fire hose can be stopped quickly as water level nears top of air vent.  Check by sounding or ullage through the air vent, that water level in forward air vents has also risen towards top of air vents. Hold level for 30 minutes minimum and check if level in vent is falling or steady.  Look for leaks.