watchkeeping full Flashcards
(94 cards)
Why do you have 3 thrusters instead of one big one?
better maouverability and redundancy
Advantages of high voltage
requires less current when voltage is higher. this reduces resistance allowing for thinner wire to be used and saves energy
High voltage sanctions
high voltage sanctions are essentially permits to work from an authorised person to allow work on isolated hv equipment
PPE to work on high voltage stuff
gloves, insulated boots, goggles/faceshirld, boilersuit. Hard hat depending on location
Draw me a rectifier
uses diodes in wheatstone bridge type formation to convert ac to dc
Draw me a circuit showing rectification from AC to DC
Draw me a zenor diode
What batteries did you have on your lifeboat?
lead acid
What else did you have to help start your lifeboat?
2 seperate battery banks to start from. could also have a manual start method with handcrank
Maintenance on batteries
check case for any signs of wear or damage.
top up electrolyte levels.
check terminals for damage and wear. check for any signs of leaks. check all wires are in good condition.
always use insulated tools and ensure correct ppe is worn
What material are battery terminals made of lifeboat
Lifeboat battery terminals are typically made from lead or lead alloys, similar to those used in most automotive and marine batteries. Lead is chosen for its excellent conductivity, corrosion resistance (especially in harsh marine environments), and ability to withstand the chemical reactions that occur within a battery. In some cases, the terminals may also be coated or mixed with other metals like tin or calcium to enhance durability and performance.
Causes of high exhaust temp
Excess Fuel Supply: Over-fueling due to faulty injectors (e.g., enlarged nozzle holes from wear) or a malfunctioning fuel pump can lead to incomplete combustion, with excess fuel burning in the exhaust system, raising temperatures.
Poor Fuel Quality: Low-quality or improperly treated fuel (e.g., heavy fuel oil with high viscosity or contaminants) can burn inefficiently, increasing exhaust heat. Inadequate fuel purification exacerbates this.
Insufficient Air Supply: Restricted airflow from clogged air filters, fouled turbocharger components (e.g., nozzle ring or turbine blades), or a dirty charge air cooler reduces oxygen availability, leading to incomplete combustion and hotter exhaust gases.
Exhaust Valve Issues: Leaking or worn exhaust valves allow combustion gases to escape prematurely into the exhaust manifold, where they continue burning, elevating temperatures.
Turbocharger Problems: A fouled or damaged turbocharger reduces boost pressure, limiting air intake and causing richer combustion mixtures that increase exhaust heat. Excessive backpressure from blockages can also contribute.
Increased Engine Load: Overloading from hull fouling, damaged propellers, or operational demands forces the engine to work harder, generating more heat in the exhaust.
Incorrect Timing: Improper fuel injection or valve timing (e.g., delayed injection) shifts combustion later in the cycle, pushing unburnt fuel into the exhaust, where it burns and raises temperatures.
Scavenge Air Issues: Leaks or blockages in the scavenge air system (e.g., fouled ports or cooler) reduce the air available for combustion, leading to higher exhaust temperatures.
Afterburning or Scavenge Fire: Unburnt fuel or oil in the exhaust manifold or scavenge space can ignite, significantly increasing exhaust heat.
Instrumentation Error: Faulty temperature sensors or pyrometers might falsely indicate high exhaust temperatures, so verification is key.
Where would you record changing an injector
engine log and nox technical file
What’s your PMS system
planned maintenance system
What would you do if high and rising bilge alarm
acknowledge alarm
locate bilge and check level.
determine if there is flood condition
open valve for bilge well in alarm. ensure correct lineup of vavles from bilge to bilge holding tank through pump.
sound bilge holding tank
start pumping operation
once bilge holding tank is empty, stop the pump. record volume transferred
close bilge well valve
What is SMS
a formal, organization-wide approach to managing safety risks, including procedures, practices, and policies, ensuring the safe operation of vessels and protecting the marine environment.
What documents do we have that come under SMS
emergency procedures
engineering sops
reporting procedures
detail of designated person ashore
ducument of compliance
Marpol chapters
oh no, here she goes again
What goes in your oil record book
Discharges of oil or oily mixtures from machinery space.
Transfer of oil or oily mixtures within the vessel.
Operations related to oil filtering equipment.
Bunkering operations.
Any failures of oil filtering equipment or oil discharge monitoring and control systems.]
Tank number, location, type of oil, description of operation, and quantity.
Time and date of the operation.
Place or position of the ship at the time of the operation.
Circumstances of discharge or escape, the reasons there for and general remarks.
What equipment do we have onboard under marpol annex one
oil water seperator
NOX and SOX limits
nox varies depending on engine type. sox is 0.5% and 0.1% by mass in eca
How scrubbers work
spraying water on exhaust gas. low temperatuire condenses sulper
What would you do with cooking oil a chef gave you to dispose of in engine room
hold in sealed metal buckets until discharge is possible to shoreside waste facility
Asked about what caused high exhaust temp in one cylinder and how this correlated to indication cards.
High exhaust temperature in one cylinder of an internal combustion engine typically indicates an issue with combustion or engine operation specific to that cylinder. This can stem from several potential causes, and its correlation to indicator cards (pressure-volume or pressure-time diagrams from an engine cylinder) can provide diagnostic clues. Here’s an explanation:
Causes of High Exhaust Temperature in One Cylinder
Lean Fuel-Air Mixture:
If the air-fuel mixture is too lean (excess air, insufficient fuel), combustion burns hotter and slower, increasing exhaust gas temperature (EGT). This might result from a clogged injector, fuel delivery issue, or intake air imbalance.
Indicator Card Correlation: A lean mixture often shows a delayed peak pressure (shifted toward the exhaust stroke) and a lower maximum pressure due to incomplete combustion.
Overfueling (Rich Mixture):
Excess fuel can lead to prolonged combustion into the exhaust stroke, raising EGT. This might occur due to a faulty injector dumping too much fuel.
Indicator Card Correlation: You’d see a higher-than-normal peak pressure, potentially with a “tail” of pressure extending later in the cycle, indicating late burning.
Ignition or Injection Timing Issues:
If ignition (in spark-ignition engines) or injection (in diesel engines) occurs too late, combustion extends into the exhaust phase, elevating EGT.
Indicator Card Correlation: Late timing shifts the peak pressure further from top dead center (TDC), reducing efficiency and showing a delayed pressure rise.
Valve Malfunction:
A leaking or stuck exhaust valve prevents proper sealing, allowing hot combustion gases to escape prematurely or backflow, raising EGT. Alternatively, poor intake valve operation can disrupt the air-fuel charge.
Indicator Card Correlation: A leaking exhaust valve might show reduced peak pressure and an abnormal pressure drop during the expansion stroke.
