Exam Question
A new vessel exhibits severe aft end vibrations.
(a) As a Second Engineer Officer, outline a procedure to investigate and identify the source of vibration
(b) Suggest possible remedies to obviate/reduce aft end vibration.
Class 2 (2nd Engineer)
MEKG
📅 Feb 2018
Reference Answer
(a) As a Second Engineer Officer, the following steps can be undertaken to investigate and identify the source of aft-end vibration:
Monitor vibration levels at different engine speeds, particularly checking for critical speed ranges. Note any changes in vibration during varying operational conditions, such as ballast versus loaded conditions.
Inspect the propeller blades for signs of damage, such as broken or deformed sections. This can be done during ballast condition by trimming the ship if necessary or during dry dock.
Measure the wear-down of the intermediate shaft bearings and stern tube bushes. Excessive wear can cause misalignment and drooping of the shaft, leading to vibrations.
Monitor vibration levels at different engine speeds, particularly checking for critical speed ranges. Note any changes in vibration during varying operational conditions, such as ballast versus loaded conditions.
Inspect the propeller blades for signs of damage, such as broken or deformed sections. This can be done during ballast condition by trimming the ship if necessary or during dry dock.
Measure the wear-down of the intermediate shaft bearings and stern tube bushes. Excessive wear can cause misalignment and drooping of the shaft, leading to vibrations.
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