USCG Alert
The Coast Guard issued a reminder for owners and operators to routinely inspect their mechanical parts and electrical components to avoid preventable casualties.
The Coast Guard suggests that owners, operators, marine engineers and others, particularly onboard or associated with older vessels, think about and identify those high risk components which if a failure or malfunction occurs will result in a casualty. High risk components include those that are subject to gradual wear, tear or loosening. |
Sometimes it is the most seemingly minor thing such as amechanical part or electrical component that can lead to a catastrophe. For example, a nearly 20 yearold bulker was leaving port when its main engine throttle failed. In this case the vessel was able todrop anchor without incident.
The failure occurred because a small drive beltthat connected the console throttle levercomponents to an electrical potentiometerfailed. Movement of the throttle causes thepotentiometer to move and creates a variablesignal to other controls which manage enginespeed.
When the belt failed the control from theengine room console was lost. Fortunately, thevessel had a spare belt that the engineersreplaced quickly. The underside of theBosch/Rexroth throttle was encased and thebelt was not visible under normalcircumstances. Routine inspection of the beltdid not occur.
Other examples:
- A contact in a small electricalrelay and part of the autopilot system stuck andcaused a vessel to go hard to port at 24 knots;
- Three of four nuts on a propeller shaft sealloosened, went unnoticed and caused flooding of the machinery space of an Offshore Supply vessel;
- A wire chafed and grounded out cutting power to critical combustion controls while a vessel was atthe dock, but not long after transiting a narrow Caribbean harbor entrance.
The Coast Guard recognizes that identifying every single failure mode that could possibly impact avessel’s propulsion, power generation system or steering system and developing a comprehensivepreventative maintenance system for such systems, equipment and components is a very complextask Nevertheless, the Coast Guard suggests that owner operators, marine engineers and othersparticularly onboard or associated with older vessels, think about and identify those high riskcomponents which if a failure or malfunction occurs will result in a casualty. (Specifically componentssubject to gradual wear and tear or loosening.) Once identified responsible personnel should refer totheir respective manuals to determine proper maintenance requirements and take the necessarysteps to prevent a future problem with the aim to reduce risk. |
Source & Image Credit : USCG Marine Safety Lessons Learned 1-14