32 Questions
What is the relationship between the mass, volume of displacement, and water density for vessels floating in water?
basic principles
What will learners be able to determine by applying their basic knowledge of vessel floating scenarios?
draught at which a ship will float in water of a given density
How will the rate of change of draught with changing displacement be investigated?
Both a and b
The concept of free surface is not important in determining the final stability of a vessel.
False
Learners should be able to determine the angle of _____ for small angles when there is a transverse shift of weight within the vessel.
list
What does STCW stand for?
Standards of Training, Certification and Watchkeeping for Seafarers
Which control system component is responsible for managing commands to regulate the behavior of other devices?
Feedback
___ means the difference between the measured and desired values in a closed loop control system.
Deviation
Match the following ship control systems with their functions:
PMS (Power Management System) = Manages power for generators Dynamic positioning (station-keeping) = Maintains ship's position without anchoring Boiler combustion control = Regulates combustion in the boiler
What is the unit code for the Ship Stability: An Introduction unit?
HR06 34
What principles are applied in Outcome 1 of the Ship Stability unit?
Hydrostatics and Loadline calculations
Interpreting GZ curves is part of Outcome 2 in the Ship Stability unit.
True
The Ship Stability unit introduces __________ stability in Outcome 2.
longitudinal
Match the following components with the Ship Stability unit outcomes:
- Initial transverse metacentre
- True Mean Draught (TMD)
- Centre of Buoyancy
- Hydrometer use
1 = Outcome 2 - Principle of statical stability 2 = Outcome 4 - Principle of longitudinal stability 3 = Outcome 3 - Principle of transverse stability 4 = Outcome 1 - Basic principles of hydrostatics
What is the purpose of VDR (Voyage Data Recorder) according to SOLAS regulations?
data recording system designed to collect data from various sensors on board the vessel
Which of the following movements are logged and recorded in the bridge telegraph data logger?
Half Astern
What must the power supply shut down alarm do when power is off to VDR?
activated, continue to operate for at least 1 hour 55 minutes, stop recording no later than 2 hours 5 minutes after power is removed
The mimic control system for water tight doors on vessels must have LED indications to show the status of the doors as per SOLAS regulations.
True
What is the principle of bridge control for slow speed diesel engines?
fail safe, fail run, safety interlocks
What components are included in the bridge control system for steam turbines with associated boilers?
transmitter, direction controller, function generator, speed controller
What is required for interchanging control from engine room to bridge or vice versa to avoid damage to the main engine?
Alignment of telegraph positions
An integrated bridge system (IBS) is interconnected to allow centralized monitoring of various navigational tools.
True
What should be done if the remote control fails during bridge operation of the main engine?
Transfer control to the engine room immediately
The camless engine relies on camshafts for valve operation.
False
What is the purpose of scavenge ports in a 2-stroke engine?
Scavenge ports allow air to enter the engine for combustion.
The sudden build-up in pressure that finds an escape route around the burner cover or through the furnace sight glass is known as ___.
blowback
What is a control system without feedback called?
open loop control
What is the purpose of a control system?
to manage commands, direct, or regulate the behavior of other devices or systems
What are the types of control action for control systems?
All of the above
An open loop control system does not adjust its output based on feedback.
True
Match the type of signal with its description:
Analogue Signals = Vary smoothly and continuously with time Digital Signals = Have only two states - on or off
What are mimic diagrams used for?
displaying various systems in a visual manner
Study Notes
Unit Overview
- Unit title: Ship Stability: An Introduction (SCQF level 7)
- Unit code: HR06 34
- Superclass: XQ
- Publication date: September 2017
- Source: Scottish Qualifications Authority
- Version: 2
Unit Purpose
- Applies principles of ship stability for box and ship shape vessels to routine situations
- Develops knowledge of hydrostatics, loadline calculations, statical stability, and longitudinal stability
- Aimed at learners seeking sea-going employment as Merchant Navy Deck Officers
- Also suitable for those with an interest in the subject area
Outcomes
Outcome 1: Apply Basic Principles of Hydrostatics to Loadline Calculations
- Knowledge and/or skills:
- Vessel displacement
- Mass, volume, density, and relative density
- Archimedes' principle, hydrostatic data, displacement volume, displacement, buoyancy
- Waterline length, breadth, draught, LBP, AW, CW, CB, and freeboard
- TPC, FWA, and dock water allowance
- Displacement, deadweight, and TPC tables
- Loadline and draught marks
- Loadline calculation
- Hydrometer use
Outcome 2: Apply Principles of Statical Stability to Interpret GZ Curves
- Knowledge and/or skills:
- Centre of buoyancy, centre of gravity, initial transverse metacentre, righting lever, righting moment
- Stable, neutral, and unstable conditions of stability at small angles of heel
- GZ curves
- Stiff and tender vessels
- Angle of loll
Outcome 3: Apply Principles of Transverse Stability to List Calculations
- Knowledge and/or skills:
- Effect on G of loading, discharging, and moving weights
- List
- Difference between list and loll and the methods of correction
- Changes in stability during the voyage
- Free surface and the dangers and effect at small angles of heel
- Effect of tank subdivision and density on free surface
- Allowance for the effect of free surface
Outcome 4: Apply Principles of Longitudinal Stability to Draught Calculations
- Knowledge and/or skills:
- True Mean Draught (TMD), Longitudinal Centre of Flotation (LCF), Longitudinal Centre of Gravity (LCG), Longitudinal Centre of Buoyancy (LCB), Trimming Moment, and Moment to Change Trim 1 cm (MCTC)
- Apply principles of longitudinal stability to calculations involving the inter-relationship of draught, trim, weight, and their positions### Ship Stability: An Introduction (SCQF level 7)
- Applies principles of ship stability to routine situations for box and ship shape vessels
- Covers hydrostatics, loadline calculations, statical stability, transverse stability, and longitudinal stability
- Assesses the use of the hydrometer and aspects of loadlines, structural, transverse, and longitudinal stability under supervised conditions
- May use computer software used typically aboard ship
- Develops Using Number and Using Graphical Information components of Numeracy, and the Critical Thinking component of Problem Solving
Assessment
- May combine outcomes for assessment lasting no longer than two hours
- E-assessment may be used, with national standards applied to all learner evidence
- Conditions of assessment must be met, regardless of mode of gathering evidence
Core Skills
- Critical Thinking at SCQF level 6
- Using Number at SCQF level 6
- Using Graphical Information at SCQF level 5
Voyage Data Recorder (VDR)
- Mandatory by SOLAS
- Designed for all vessels required to comply with IMO's Requirements (IMO Res.A.861 (20))
- Collects data from various sensors on board the vessel
Power Supply to VDR
- Power supply shut down alarm must be activated when power is off to the VDR
- Equipment continues to operate for at least 1 hour 55 minutes and automatically stops recording no later than 2 hours 5 minutes after external power is removed
- Confirm that batteries within the equipment for power supply to the acoustic beacon are satisfactory at all times
Bridge Telegraph Data Logger
- Records navigational activities and incidents which are of importance to safety of navigation
- Contains sufficient detail to restore a complete record of the voyage
- Based on SOLAS chapter V, Annex 21
- Digital data recording system introduced on board ship
- Bridge data logger is part of this requirement
- Must be approved by the classification society or administration
Mimic Control for Ship's Watertight Door
- Used on modern vessels at the navigational bridge to operate the watertight door
- Meets regulatory requirements of MSC.1/Circ. 1380 Guidance for watertight doors and SOLAS chapter V, reg/20
- Mimic board using for controlling the watertight door on the navigation bridge must have a red light LED indication by flashing at the intermediate position when the door is remotely operating
Marine Engineering Systems
- Covers control systems, terminology, open and closed loops, types of control action, and practical shipboard applications
- Includes data loggers, mimic diagrams, analogue and digital displays, and shipboard applications
Control Systems
- Definition: A system that manages, commands, directs, or regulates the behavior of other devices or systems to achieve desired results
- Types: open-loop and closed-loop control systems
- Terminology: desired value, set value, deviation, offset, feedback, control action, measuring element, controlled condition, and correcting unit
Open and Closed Loops
- Open-loop: control action independent of system output
- Closed-loop: control action dependent on system output, using feedback to adjust control action
Types of Control Action
- Proportional action: output signal proportional to input signal
- Integral action: output signal proportional to integral of input signal
- Derivative action: output signal proportional to derivative of input signal### Control Systems in Marine Engineering
- A control system is a system that manages, commands, directs, or regulates the behavior of other devices or systems to achieve desired results.
- Open Loop Control: A control system without feedback.
- Components: Input, Process, Output
- Example: Manual steering operation from the local station by observing the rudder angle manually.
- Closed Loop Control: A control system with feedback.
- Components: Input, Process, Output, Feedback Link
- Example: Steering operation from the bridge through the telemotor and hunting gear system, which works as a feedback link.
Types of Control Action
- Proportional Control Action:
- The output signal is proportional to the input signal.
- Integral Control Action (Reset):
- The output signal changes at a rate proportional to the input signal.
- Derivative Control Action:
- The output signal is proportional to the rate of change of the input signal.
Proportional Band
- The range of values of deviation corresponding to the full operating range of the output signal of the controlling unit, resulting from proportional action only.
- Expressed as a percentage of the range of values of the controlled condition.
Regulating Unit
- The most common type of regulating unit found at sea is the pneumatic control valve.
- Valve operation can be direct-acting or reverse-acting.
- Control valves can regulate the flow or control the percentage of fluid flowing in each direction.
Limitations of Controllers
- Pneumatic systems require clean, dry air supply.
- Electrical systems are susceptible to temperature and vibration faults.
- Mechanical systems suffer from friction, temperature, and vibration.
- Hydraulic systems require clean oil and are prone to leaks.
Shipboard Applications
- Jacket water temperature control system
- Boiler water level control system
- Data loggers, mimic diagrams, and analogue and digital displays are used in shipboard applications.
Bridge Control
- Principles of bridge control:
- Fail safe, fail run, and safety interlocks for slow speed diesel engines, medium speed diesel engines, steam/gas turbines, and thruster systems.
- Interchanging bridge and engine room control.
- Requirements for plant monitoring and alarm systems for UMS operations:
- Solas requirements for control of propulsion equipment, centralized control, and automatic fire detection and alarm systems.
- Protection against flooding, and bilge well requirements.
Integrated Bridge Systems
- Combines various systems to allow centralized monitoring of navigational tools.
- Includes autopilot, radar, gyro, position fixing systems, ECDIS, power distribution system, and steering gear.
- Alarm system links all systems and provides audio and visual signals in case of emergency conditions.
This unit covers the principles of ship stability for box and ship shape vessels, applying them to routine situations. It develops knowledge of ship stability principles.
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