GPS satellites are positioned at an altitude of 20,200 km above the Earth's surface, which falls within medium Earth orbits. This height provides global coverage with a smaller number of satellites and allows earth-based transmitters and receivers to use modest sized antennas and lower transmission powers.
Gross tonnage refers to the total enclosed volume of a ship, while net tonnage refers to the cargo-carrying capacity. Both are determined by measuring volumes and applying formulas, and are dimensionless numbers rather than units of mass.
Radar performance can be ascertained using a performance monitor. 10 cm or S-band radar is generally better for long range scanning and in heavy rain due to less clutter.
The document provides information on the International Aeronautical and Maritime Search and Rescue (IAMSAR) Manual. It discusses that IAMSAR is a joint publication of ICAO and IMO that assists states in meeting SAR needs and obligations under international conventions. It has three volumes that deal with specific SAR system duties and can be used independently or together. The document then provides definitions and explanations of key terms related to SAR operations, structures, and coordination.
1. The document discusses various types of errors that can occur in marine gyrocompasses, including latitude error, course and speed error, and ballistic deflection.
2. Latitude error, also called damping or settling error, causes the gyro spin axis to settle slightly off true north due to eccentricities in the damping mechanism. This introduces a small error that can be calculated based on latitude.
3. Course and speed error, also called steaming error, occurs because the gyro senses the combined rotation of the Earth and ship's movement, not just Earth's rotation. This introduces an error that depends on latitude, course, and speed.
4. Ballistic deflection is an error caused by accelerations from changes
Presentation on maneuvering and collision avoidance with special focus on large tonnage vessels.
Maneuverability limits and last moment maneuver are thoroughly shown in this material.
This document discusses planning and executing blind pilotage and anchoring. It defines blind pilotage as navigation through restricted waters with little visual observation. It emphasizes assessing risk, using parallel indexing techniques on radar displays to monitor position relative to the planned track, and establishing clearing ranges to stay clear of dangers. It outlines responsibilities of the navigating officer and blind pilotage team, and provides guidance on planning, execution, exercises and record keeping to safely conduct blind pilotage and anchoring.
Pertanyaan dan jawaban interview cadet deckahmadhamir
This document provides information about conventions and regulations, life saving appliances, firefighting equipment, and navigation equipment relevant for a cadet deck interview. It discusses the key international conventions like SOLAS, STCW, MARPOL and ILO-MLC which establish global standards. It also summarizes some important life saving appliances, fire safety systems, and navigation equipment found on ships. Finally, it explains the IALA system of navigational buoys and their meanings.
The document discusses factors affecting ship handling both internally and externally. Internal factors include engine power, propeller, rudder, anchors, and thrusters. External factors include tide, wind, current, proximity of other vessels, and harbor depth. It then discusses principles of ship handling and how ships move longitudinally, laterally, and rotationally. Finally, it discusses the effects of wind and current on ship handling in detail covering topics like windage area, trim, headway, and sternway.
This document discusses classification societies and their role in classifying ships. Classification societies set technical and safety standards for ships and ensure they are properly maintained through regular surveys. They assign ships a class rating which is valid for typically 5 years and indicates the risk level for insurers. Major classification societies around the world include Lloyd's Register, American Bureau of Shipping, Bureau Veritas, Det Norske Veritas, and others.
The document provides information on the International Aeronautical and Maritime Search and Rescue (IAMSAR) Manual. It discusses that IAMSAR is a joint publication of ICAO and IMO that assists states in meeting SAR needs and obligations under international conventions. It has three volumes that deal with specific SAR system duties and can be used independently or together. The document then provides definitions and explanations of key terms related to SAR operations, structures, and coordination.
1. The document discusses various types of errors that can occur in marine gyrocompasses, including latitude error, course and speed error, and ballistic deflection.
2. Latitude error, also called damping or settling error, causes the gyro spin axis to settle slightly off true north due to eccentricities in the damping mechanism. This introduces a small error that can be calculated based on latitude.
3. Course and speed error, also called steaming error, occurs because the gyro senses the combined rotation of the Earth and ship's movement, not just Earth's rotation. This introduces an error that depends on latitude, course, and speed.
4. Ballistic deflection is an error caused by accelerations from changes
Presentation on maneuvering and collision avoidance with special focus on large tonnage vessels.
Maneuverability limits and last moment maneuver are thoroughly shown in this material.
This document discusses planning and executing blind pilotage and anchoring. It defines blind pilotage as navigation through restricted waters with little visual observation. It emphasizes assessing risk, using parallel indexing techniques on radar displays to monitor position relative to the planned track, and establishing clearing ranges to stay clear of dangers. It outlines responsibilities of the navigating officer and blind pilotage team, and provides guidance on planning, execution, exercises and record keeping to safely conduct blind pilotage and anchoring.
Pertanyaan dan jawaban interview cadet deckahmadhamir
This document provides information about conventions and regulations, life saving appliances, firefighting equipment, and navigation equipment relevant for a cadet deck interview. It discusses the key international conventions like SOLAS, STCW, MARPOL and ILO-MLC which establish global standards. It also summarizes some important life saving appliances, fire safety systems, and navigation equipment found on ships. Finally, it explains the IALA system of navigational buoys and their meanings.
The document discusses factors affecting ship handling both internally and externally. Internal factors include engine power, propeller, rudder, anchors, and thrusters. External factors include tide, wind, current, proximity of other vessels, and harbor depth. It then discusses principles of ship handling and how ships move longitudinally, laterally, and rotationally. Finally, it discusses the effects of wind and current on ship handling in detail covering topics like windage area, trim, headway, and sternway.
This document discusses classification societies and their role in classifying ships. Classification societies set technical and safety standards for ships and ensure they are properly maintained through regular surveys. They assign ships a class rating which is valid for typically 5 years and indicates the risk level for insurers. Major classification societies around the world include Lloyd's Register, American Bureau of Shipping, Bureau Veritas, Det Norske Veritas, and others.
The document discusses autopilot systems and steering gear controls on ships. It provides details on:
- How autopilots work to automatically steer the ship and reduce workload in heavy weather by learning a ship's handling characteristics.
- The different control modes and settings used on autopilot control units, including proportional, integral, derivative controls and weather compensation settings.
- Limitations of autopilot use in rough conditions, tight spaces, slow speeds, or during maneuvers.
- Procedures for changing between manual and autopilot steering, testing equipment, and emergency steering protocols.
The document discusses characteristics of waves and heavy weather conditions at sea. It defines key terms like wave height, length, and period. It describes how wind speed affects wave development. It explains dangers like broaching, pooping, hogging and sagging in heavy seas. It provides guidance on ship handling in different sea conditions, including turning, heaving to, and reducing speed. The overall focus is on understanding wave behavior and taking proper precautions to avoid damage to ships in heavy weather.
Final report Ship Handling and Manuevering 05-13-22.pptxNieLReSpiCiO
The document provides information on proper procedures for mooring, docking, and undocking ships. It discusses topics such as mooring lines, types of mooring (e.g. Mediterranean mooring), line handling procedures, docking maneuvers, and tips for safely docking and undocking a vessel. Key points include the different types of mooring lines used to secure a ship, the importance of communication and having a plan when maneuvering near docks, and approaching docks slowly with fenders in place for protection.
The document defines and describes various parts of a ship. It identifies the bow and stern as the front and back of the ship. It explains that the hull is the part that is partly in the water and carries cargo in holds, while the freeboard is the part above the water and the draught is the part below. It also outlines key features like the propeller that propels the ship forward, the rudder that controls turning, lifeboats for emergency evacuation, and the bridge that serves as the ship's control center.
This document discusses blind pilotage, which is navigating a ship through restricted waters with limited visibility. It describes how radar is used as the primary method of navigation in these conditions. It also outlines some of the errors that can occur with radar, such as index errors, strobe accuracy issues, and errors introduced by controls. The document provides guidance on planning a track, monitoring position relative to the track, and maintaining safe water while blind piloting a ship.
This document discusses navigation and collision avoidance in restricted visibility. It outlines key rules for vessel conduct when visibility is limited, including proceeding at a safe speed and having engines ready. Parallel indexing is described as the primary method for monitoring navigation using radar to track fixed objects and course changes. The document also details the sound signals vessels must use in restricted visibility, such as one prolonged blast for power-driven vessels making way through water. Maintaining accurate position information and pre-planning routes can additionally aid safe navigation in poor conditions.
ECDIS: New standards & old underwater rocksLearnmarine
Webinar on: IHO S-52 Presentation Library 4.0, ECDIS as an anti-grounding device, Safety Contour and Safety Depth setup, information layers, utilities.
This document summarizes a study on simulating the motion response of an intact and damaged ship in head waves using computational fluid dynamics (CFD). It describes setting up CFD cases to analyze the heave and pitch motions of an intact ship model in regular head waves of varying wavelengths. The study also simulates a damaged ship condition and compares the motion responses to the intact case. Areas identified for future work include modeling water intrusion during flooding and simulating more complex sea states with irregular waves.
The document summarizes the International Regulations for the Prevention of Collisions at Sea (1972). It outlines the layout and key parts of the regulations, including steering and sailing rules, actions between vessels, use of shapes and lights to identify vessels, and rules for narrow channels, overtaking, meeting head-on, and more. The regulations establish uniform navigation rules to prevent collisions between vessels.
Compass errors arise from two sources: variation and deviation. Variation is the difference between magnetic and true north, while deviation is caused by nearby magnetic interference. Compass error is the sum of variation and deviation, representing the angle between true and compass north. Finding transit or gyro errors allows one to determine the compass error. Regular corrections are needed since errors change with location and vessel orientation.
1. The document outlines the roles and responsibilities of the bridge watchkeeping team, including conducting regular checks of navigational equipment, compliance with collision regulations, and navigation procedures in different conditions.
2. It describes the roles of the Master, Officer of the Watch, helmsman, lookout, and pilot in ensuring safe navigation and navigation in compliance with international regulations.
3. Effective communication and coordination between all bridge team members is essential for safe navigation.
This document discusses longitudinal stability and trim in ships. It defines key terms like trim, longitudinal center of flotation, trimming moment, and moment to change trim. It describes how trim occurs when the forward and aft drafts are unequal and explains how small weight changes affect trim. Weight shifts produce a trimming moment that changes the trim according to the trimming moment divided by the moment to change trim. The changes in forward and aft draft are then calculated based on the new trim.
The document summarizes the key parts and rules of COLREGS (Convention on the International Regulations for Preventing Collisions at Sea). It is divided into 5 parts, with Part A covering general rules about application and responsibilities, Part B covering steering and sailing rules for vessels in sight of each other or any visibility condition, Part C covering lights and shapes, Part D covering sound signals, and Part E covering exemptions. Key rules discussed in Part B include safe speed, action to avoid collisions, narrow channels, traffic separation schemes, and specific rules on sailing vessels, overtaking, head-on, and crossing situations.
Static forces on a ship include internal forces from structural weight and cargo and external static forces from hydrostatic pressure. Dynamic forces result from ship motion at sea, wind and waves, and operating machinery. A ship has six degrees of freedom of motion: rolling, surging, pitching, swaying, heaving, and yawing. Ship motion introduces dynamic forces that cause stresses on the ship's structure. Methods to reduce rolling include bilge keels, passive tanks, controlled passive tanks, active tanks, and fin stabilizers.
This document provides an introduction to key ship handling terms and commands for navigating a ship. It defines basic terms like bow, stern, port, and starboard. It outlines standard engine commands by speed range and rudder commands by degree or common term. Maneuvering commands are described that combine engines and rudders. Ship handling concepts of split-ship and twist maneuvers are introduced. Precise speed and course adjustments are also covered, along with mooring and the 3-2-1 distance rule for other vessels.
This document provides an overview of shiphandling theory and practices. It covers key topics such as laws of motion, controllable and uncontrollable forces acting on a ship, terminology, ground tackle, mooring, getting underway, single and twin screw characteristics, standard commands between the conning officer and helm, and maneuvering considerations. The document is intended to teach the essential information needed for shiphandling watches and operations.
The document provides guidance on passage planning for ships. It discusses key terms, guidelines and components to consider when creating a passage plan. The main components are appraisal, planning, execution and monitoring. Appraisal involves considering relevant information about the ship, cargo, crew, and voyage. Planning includes plotting the intended route on charts and noting safety elements. Execution is conducting the passage according to the plan, adjusting as needed. Monitoring involves checking progress and equipment performance against the plan. The overall purpose is to ensure safe and efficient navigation while protecting the environment.
The document provides information on various bridge equipment used on ships including:
- AIS automatically transmits ship information like identification, position, speed to other vessels and coast stations.
- Weather facsimile systems receive synoptic charts via radio signals from coastal stations.
- Auto pilots control the rudder to maintain a set course using rudder, counter-rudder and yaw controls.
- Speed logs like the EMF and Doppler logs measure the ship's speed through and over the water respectively.
- GPS uses satellite signals to determine position within 10-15 meters accuracy. DGPS improves this to 3-5 meters.
- Radar uses radio pulses to detect targets and their range
The document outlines the duties and responsibilities of the Officer of the Watch (OOW) according to STCW regulations. The OOW is primarily responsible for the safe navigation of the ship and compliance with collision regulations. Key duties include maintaining a proper lookout, navigating the ship according to the passage plan, using all navigational equipment, communicating via radio, and notifying the master immediately of any issues or hazards. The OOW must execute their duties safely and in accordance with international regulations.
The document discusses various types of charts used for ocean navigation including routeing charts, wave charts, ice charts, and current charts. Routeing charts are published monthly for major ocean basins and contain information about winds, temperatures, currents, shipping routes and hazards. Wave charts show historic and predicted wave heights and directions. Ice charts indicate ice coverage and are used to plan safe routes. Current charts display ocean circulation patterns to aid efficient voyages. Additional sources of marine weather data include Navtex broadcasts.
This document discusses various factors that can be used to determine the optimum shipping route, including monthly routeing charts, wave charts, ice charts, current information, prevailing winds, ice conditions, and other weather information sources like Navtex. Monthly routeing charts provide data on winds, temperatures, currents, and ice limits to assist navigators in planning ocean passages. Wave charts show actual and predicted wave heights and directions. Ice charts indicate ice amounts, pack locations, and iceberg positions. Current information is important for reducing travel time and fuel costs. Prevailing winds are the dominant wind patterns in different regions. Ice conditions vary by location and season. Navtex broadcasts navigational warnings and weather updates to ships.
The document discusses autopilot systems and steering gear controls on ships. It provides details on:
- How autopilots work to automatically steer the ship and reduce workload in heavy weather by learning a ship's handling characteristics.
- The different control modes and settings used on autopilot control units, including proportional, integral, derivative controls and weather compensation settings.
- Limitations of autopilot use in rough conditions, tight spaces, slow speeds, or during maneuvers.
- Procedures for changing between manual and autopilot steering, testing equipment, and emergency steering protocols.
The document discusses characteristics of waves and heavy weather conditions at sea. It defines key terms like wave height, length, and period. It describes how wind speed affects wave development. It explains dangers like broaching, pooping, hogging and sagging in heavy seas. It provides guidance on ship handling in different sea conditions, including turning, heaving to, and reducing speed. The overall focus is on understanding wave behavior and taking proper precautions to avoid damage to ships in heavy weather.
Final report Ship Handling and Manuevering 05-13-22.pptxNieLReSpiCiO
The document provides information on proper procedures for mooring, docking, and undocking ships. It discusses topics such as mooring lines, types of mooring (e.g. Mediterranean mooring), line handling procedures, docking maneuvers, and tips for safely docking and undocking a vessel. Key points include the different types of mooring lines used to secure a ship, the importance of communication and having a plan when maneuvering near docks, and approaching docks slowly with fenders in place for protection.
The document defines and describes various parts of a ship. It identifies the bow and stern as the front and back of the ship. It explains that the hull is the part that is partly in the water and carries cargo in holds, while the freeboard is the part above the water and the draught is the part below. It also outlines key features like the propeller that propels the ship forward, the rudder that controls turning, lifeboats for emergency evacuation, and the bridge that serves as the ship's control center.
This document discusses blind pilotage, which is navigating a ship through restricted waters with limited visibility. It describes how radar is used as the primary method of navigation in these conditions. It also outlines some of the errors that can occur with radar, such as index errors, strobe accuracy issues, and errors introduced by controls. The document provides guidance on planning a track, monitoring position relative to the track, and maintaining safe water while blind piloting a ship.
This document discusses navigation and collision avoidance in restricted visibility. It outlines key rules for vessel conduct when visibility is limited, including proceeding at a safe speed and having engines ready. Parallel indexing is described as the primary method for monitoring navigation using radar to track fixed objects and course changes. The document also details the sound signals vessels must use in restricted visibility, such as one prolonged blast for power-driven vessels making way through water. Maintaining accurate position information and pre-planning routes can additionally aid safe navigation in poor conditions.
ECDIS: New standards & old underwater rocksLearnmarine
Webinar on: IHO S-52 Presentation Library 4.0, ECDIS as an anti-grounding device, Safety Contour and Safety Depth setup, information layers, utilities.
This document summarizes a study on simulating the motion response of an intact and damaged ship in head waves using computational fluid dynamics (CFD). It describes setting up CFD cases to analyze the heave and pitch motions of an intact ship model in regular head waves of varying wavelengths. The study also simulates a damaged ship condition and compares the motion responses to the intact case. Areas identified for future work include modeling water intrusion during flooding and simulating more complex sea states with irregular waves.
The document summarizes the International Regulations for the Prevention of Collisions at Sea (1972). It outlines the layout and key parts of the regulations, including steering and sailing rules, actions between vessels, use of shapes and lights to identify vessels, and rules for narrow channels, overtaking, meeting head-on, and more. The regulations establish uniform navigation rules to prevent collisions between vessels.
Compass errors arise from two sources: variation and deviation. Variation is the difference between magnetic and true north, while deviation is caused by nearby magnetic interference. Compass error is the sum of variation and deviation, representing the angle between true and compass north. Finding transit or gyro errors allows one to determine the compass error. Regular corrections are needed since errors change with location and vessel orientation.
1. The document outlines the roles and responsibilities of the bridge watchkeeping team, including conducting regular checks of navigational equipment, compliance with collision regulations, and navigation procedures in different conditions.
2. It describes the roles of the Master, Officer of the Watch, helmsman, lookout, and pilot in ensuring safe navigation and navigation in compliance with international regulations.
3. Effective communication and coordination between all bridge team members is essential for safe navigation.
This document discusses longitudinal stability and trim in ships. It defines key terms like trim, longitudinal center of flotation, trimming moment, and moment to change trim. It describes how trim occurs when the forward and aft drafts are unequal and explains how small weight changes affect trim. Weight shifts produce a trimming moment that changes the trim according to the trimming moment divided by the moment to change trim. The changes in forward and aft draft are then calculated based on the new trim.
The document summarizes the key parts and rules of COLREGS (Convention on the International Regulations for Preventing Collisions at Sea). It is divided into 5 parts, with Part A covering general rules about application and responsibilities, Part B covering steering and sailing rules for vessels in sight of each other or any visibility condition, Part C covering lights and shapes, Part D covering sound signals, and Part E covering exemptions. Key rules discussed in Part B include safe speed, action to avoid collisions, narrow channels, traffic separation schemes, and specific rules on sailing vessels, overtaking, head-on, and crossing situations.
Static forces on a ship include internal forces from structural weight and cargo and external static forces from hydrostatic pressure. Dynamic forces result from ship motion at sea, wind and waves, and operating machinery. A ship has six degrees of freedom of motion: rolling, surging, pitching, swaying, heaving, and yawing. Ship motion introduces dynamic forces that cause stresses on the ship's structure. Methods to reduce rolling include bilge keels, passive tanks, controlled passive tanks, active tanks, and fin stabilizers.
This document provides an introduction to key ship handling terms and commands for navigating a ship. It defines basic terms like bow, stern, port, and starboard. It outlines standard engine commands by speed range and rudder commands by degree or common term. Maneuvering commands are described that combine engines and rudders. Ship handling concepts of split-ship and twist maneuvers are introduced. Precise speed and course adjustments are also covered, along with mooring and the 3-2-1 distance rule for other vessels.
This document provides an overview of shiphandling theory and practices. It covers key topics such as laws of motion, controllable and uncontrollable forces acting on a ship, terminology, ground tackle, mooring, getting underway, single and twin screw characteristics, standard commands between the conning officer and helm, and maneuvering considerations. The document is intended to teach the essential information needed for shiphandling watches and operations.
The document provides guidance on passage planning for ships. It discusses key terms, guidelines and components to consider when creating a passage plan. The main components are appraisal, planning, execution and monitoring. Appraisal involves considering relevant information about the ship, cargo, crew, and voyage. Planning includes plotting the intended route on charts and noting safety elements. Execution is conducting the passage according to the plan, adjusting as needed. Monitoring involves checking progress and equipment performance against the plan. The overall purpose is to ensure safe and efficient navigation while protecting the environment.
The document provides information on various bridge equipment used on ships including:
- AIS automatically transmits ship information like identification, position, speed to other vessels and coast stations.
- Weather facsimile systems receive synoptic charts via radio signals from coastal stations.
- Auto pilots control the rudder to maintain a set course using rudder, counter-rudder and yaw controls.
- Speed logs like the EMF and Doppler logs measure the ship's speed through and over the water respectively.
- GPS uses satellite signals to determine position within 10-15 meters accuracy. DGPS improves this to 3-5 meters.
- Radar uses radio pulses to detect targets and their range
The document outlines the duties and responsibilities of the Officer of the Watch (OOW) according to STCW regulations. The OOW is primarily responsible for the safe navigation of the ship and compliance with collision regulations. Key duties include maintaining a proper lookout, navigating the ship according to the passage plan, using all navigational equipment, communicating via radio, and notifying the master immediately of any issues or hazards. The OOW must execute their duties safely and in accordance with international regulations.
The document discusses various types of charts used for ocean navigation including routeing charts, wave charts, ice charts, and current charts. Routeing charts are published monthly for major ocean basins and contain information about winds, temperatures, currents, shipping routes and hazards. Wave charts show historic and predicted wave heights and directions. Ice charts indicate ice coverage and are used to plan safe routes. Current charts display ocean circulation patterns to aid efficient voyages. Additional sources of marine weather data include Navtex broadcasts.
This document discusses various factors that can be used to determine the optimum shipping route, including monthly routeing charts, wave charts, ice charts, current information, prevailing winds, ice conditions, and other weather information sources like Navtex. Monthly routeing charts provide data on winds, temperatures, currents, and ice limits to assist navigators in planning ocean passages. Wave charts show actual and predicted wave heights and directions. Ice charts indicate ice amounts, pack locations, and iceberg positions. Current information is important for reducing travel time and fuel costs. Prevailing winds are the dominant wind patterns in different regions. Ice conditions vary by location and season. Navtex broadcasts navigational warnings and weather updates to ships.
Analisis windrose (mawar angin) sangat penting untuk menentukan arah landasan pacu bandara berdasarkan arah dan kecepatan angin dominan. Data arah dan kecepatan angin diperoleh dari stasiun meteorologi terdekat selama 5 tahun terakhir untuk menunjukkan kondisi secara reliabel. Windrose mengelompokkan data berdasarkan arah dan kecepatan angin, lalu menghitung prosentase arah dominan untuk menentukan arah landasan yang memenuhi sy
Meteorology is the scientific study of the atmosphere and weather forecasting. The word was coined from Aristotle's book Meteorologica in ancient Greece, which described earth sciences including weather. Significant progress occurred in the 18th century with observing networks and breakthroughs in the 20th century after computer development. Key early inventions included Galileo's thermometer, Torricelli's barometer, and weather instruments to measure variables like wind, humidity and rainfall. Modern meteorology has benefited from technology allowing rapid data sharing and atmospheric probing with balloons, satellites and radars.
Parallel indexing is a technique used on radar to monitor a vessel's progress and maintain a safe distance from navigational hazards. It involves drawing parallel bearing lines to reference the vessel's position. Trial maneuvering simulates potential maneuvers on ARPA to avoid collisions by predicting how a vessel's course or speed change would affect surrounding targets over time. It can be run statically to immediately view results or dynamically to display predicted movements in increments. This allows evaluating different maneuvers to determine the safest option.
This document describes an experimental observation comparing the capabilities of ARPA radar and AIS systems used in vessel traffic services (VTS). Two ARPA radars and two AIS units were installed at a building near the Keelung VTS center to monitor ship movements. Information from the ARPA radars including position, course, and speed was photographed every 6 minutes, while AIS data was continuously received and stored in a database. The data was analyzed to compare which information - from ARPA radars or AIS - was more accurate and useful for VTS monitoring purposes.
1) ROTI (Rate of Turn Indicator) is an instrument that assists ship officers in planning, executing, and monitoring a vessel's progress along curved segments of its charted course. It indicates the rate of turn (in degrees per minute) to port or starboard.
2) For large vessels, turns must be executed along curved paths rather than sharp corners due to momentum and water friction. ROTI helps determine the radius and rate of turn needed based on factors like vessel size and speed.
3) There are two main turn types - constant radius, where the radius remains fixed and rate of turn varies, and constant rate, where the rate of turn remains fixed and the radius varies. The document provides
This document discusses Rate of Turn Indicator (ROTI), which is required on vessels over 50,000 GT per SOLAS regulations. ROTI assists the officer on watch in planning, executing, and monitoring a vessel's progress along a curved segment of its charted course. It provides the rate of turn to port and starboard in degrees per minute. The document derives the formula for ROT as the change in angle over time divided by the radius of the turn. It provides examples of using ROTI for constant radius and constant rate turns, and discusses wheel over points and planning turns.
Topic 1.2- Electronic Equipment used on ships (Navigational Equipment).pptxMartMantilla1
Modern ships have a variety of navigation equipment that makes navigation simpler and safer than in the past. This includes gyro compasses, radar, magnetic compasses, autopilots, ARPA, automatic tracking aids, voyage data recorders, GPS receivers, sound reception systems, and navigational lights. Together, this navigation equipment provides accurate positioning and directional information and helps ships safely plan and conduct voyages.
The document discusses finding the location of a mobile vehicle using GPL-Maps in the absence of a network. It begins by introducing the authors and abstract, which states that the proposed method can inform you of a vehicle's direction, position, and speed using a GPL Map software app on a smartphone without requiring a network connection. It then provides background on related topics like gyrocompasses, dead reckoning, and GPS before explaining the proposed method and results using Java programming. The method is presented as a novel way to locate a mobile vehicle user without the costs and limitations of other techniques that require a network.
This document provides information on several features of an ARPA radar system, including:
1. It describes how the Predicted Point of Collision (PPC) and Predicted Area of Danger (PAD) can be displayed to evaluate collision threats.
2. It explains that trial maneuvering simulations allow users to assess how targets will respond to potential course alterations before implementing them.
3. Past target positions can be shown to identify changes in course or speed over the last 8 minutes.
4. The results of trial maneuvers are approximations that depend on the system's own ship models and input course/speed alterations. Clear labeling distinguishes simulated from actual target data.
The document discusses various topics related to low visibility operations including:
1. Operating minima for different approach categories including decision heights for CAT I, II, and III approaches.
2. The microwave landing system which is capable of precision 3D navigation guidance and is intended to replace the ILS.
3. Important facilities at airports like approach lighting systems, runway markings and lights which provide visual cues for pilots during low visibility operations.
4. Factors that can affect visibility like fog which varies in density, depth and consistency depending on conditions. Shallow fog in particular can cause rapid deterioration of visibility.
Real time implemantion of stc and ftc radar system based on fpgaeSAT Journals
This document summarizes the implementation of a real-time radar signal processing system using FPGA that incorporates sensitivity time control (STC) and fast time constant (FTC) modules. The STC and FTC help filter radar echo signals to reduce effects of sea clutter and rain clutter, respectively. The architecture processes data in parallel on a sample-by-sample basis using dedicated hardware. Simulation and testing using MATLAB and on a Xilinx FPGA validated the design could process up to 100 million samples per second, meeting the requirements of commercial radar systems. The programmable FPGA platform allows flexible implementation of the real-time radar signal processing system.
This document outlines the International Maritime Organization's (IMO) performance standards for rate of turn indicators (ROTI) installed on ships. The ROTI must be capable of indicating port and starboard turns, have a means to verify operation, and use a center-zero analog dial indicator with positive indications for port and starboard turns. The scale must allow measurement of turns between -30 and 30 degrees per minute and meet accuracy standards for deviations from the actual turn rate under various ship motions and speeds.
To help ensure safe flights, air traffic controllers enforce a minim.pdfarihantpuneteleshope
To help ensure safe flights, air traffic controllers enforce a minimum time interval between
takeoffs. Explain why this time interval between takeoffs can be shortened if the wind has a
cross-runway component ( as opposed to blowing directly down the runway)?
Solution
Answer :
Use different types of air traffic pattern.
Procedures in the pattern[edit]
Aircraft are expected to join and leave the pattern, following the pattern already in use.
Sometimes this will be at the discretion of the pilot, while at other times the pilot will be directed
by air traffic control.
There are conventions for joining the pattern, used in different jurisdictions.
Similarly, there are conventions for departing the pattern.
There is also a procedure known as an \"orbit\", where an aircraft flies a 360° loop either
clockwise or anticlockwise. This is usually to allow greater separation with other traffic ahead in
the pattern. This can be the result of a controller\'s instruction. If at the pilot\'s initiative, the pilot
will report e.g. \"(tail number or flight number) making one left-hand orbit, will advise
complete\".
To practice take off and landing, a pilot would often fly many patterns, one after another, from
the same runway. Upon each landing, depending on the runway distance remaining, aircraft and
pilot capabilities, noise abatement procedures in effect, and air traffic control clearance, the pilot
will perform either a full stop landing (taxi to the runway beginning for subsequent take-off), a
touch-and-go (stabilize in the landing roll, reconfigure the aircraft for take-off, and take-off
without ever stopping the aircraft), or a stop-and-go (decelerate to a stop, then take-off from the
remaining runway). In the U.S., when operating in a controlled airport a pilot can be cleared for
the option, allowing any of the landing options above, or a rejected landing, at pilot\'s discretion.
Time interval importance in radar system.
Radar coverage
Since centers control a large airspace area, they will typically use long range radar that has the
capability, at higher altitudes, to see aircraft within 200 nautical miles (370 km) of the radar
antenna. They may also use TRACON radar data to control when it provides a better \"picture\"
of the traffic or when it can fill in a portion of the area not covered by the long range radar.
In the U.S. system, at higher altitudes, over 90% of the U.S. airspace is covered by radar and
often by multiple radar systems; however, coverage may be inconsistent at lower altitudes used
by unpressurized aircraft due to high terrain or distance from radar facilities. A center may
require numerous radar systems to cover the airspace assigned to them, and may also rely on
pilot position reports from aircraft flying below the floor of radar coverage. This results in a
large amount of data being available to the controller. To address this, automation systems have
been designed that consolidate the radar data for the controller. This consolid.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Glider Advancements in Efficiency: Enhancing Factors Necessary for Ocean-Wide...LiamRamsay
Research Paper written for the Autonomous Underwater Vehicle (AUV) Teledyne Marine Slocum Glider. Paper was published for the MTS/IEEE OCEANS Conference 2015 Washington D.C.
AIS aims to automatically identify vessels using electronic communication without human intervention. It works by having each vessel broadcast its identification and position using a transponder. Vessels are assigned time slots to transmit this data to avoid interference on the shared VHF channel. The time slots are precisely synchronized using GPS time signals. This allows many vessels to broadcast on the same frequency without interfering with each other. Vessels can then receive the identification and position of all other vessels within range, aiding navigation safety.
This document provides information about dynamic positioning (DP) systems used on vessels. It begins with a summary of DP from Wikipedia, explaining that DP uses propellers and thrusters controlled by a computer system to automatically maintain a vessel's position and heading. It then discusses the history of DP, compares DP to other position keeping methods, lists applications of DP, and describes the requirements and components of DP systems, including position reference systems. The document provides technical details about DP systems for an intermediate professional audience.
IRJET- Advanced Border Security Alert for Fishermen and Smart Data Transfer u...IRJET Journal
This document describes a system to alert fishermen when they approach national borders to prevent them from being detained by other countries like Sri Lanka. The system uses GPS to track the location of fishing boats and compare their coordinates to predefined border coordinates stored in a microcontroller. When a boat enters a warning zone near the border, the system triggers an alarm and shuts down the boat's engine. The boat's location and status are also transmitted via RF to coast guard authorities and the fishermen's family members. The goal is to protect fishermen through an affordable early warning system that notifies them of approaching borders and transmits their location for monitoring.
This document provides an overview of differential GPS (DGPS) and its history. It explains that DGPS uses fixed, ground-based reference stations to broadcast corrections to improve GPS accuracy from 15 meters to about 10 cm. Selective availability was introduced by the US military to degrade civilian GPS but was turned off in 2000. DGPS was developed as a solution, broadcasting corrections to offset errors and allow 5 meter accuracy, meeting most civilian needs. It has expanded to cover many waterways through systems like the US Coast Guard's National DGPS.
IRJET- Positioning of Underwater Vehicle using Acoustic SignalIRJET Journal
1) The document describes methods for positioning an underwater vehicle using acoustic signals. Time of arrival (TOA) and time difference of arrival (TDOA) techniques are simulated to locate the vehicle relative to acoustic beacons.
2) TOA calculates distance based on the time it takes a signal to travel between beacons and the vehicle, while TDOA uses differences in arrival times between multiple beacons.
3) Trilateration and multilateration methods are discussed. Trilateration uses TOA to three beacons, while multilateration employs TDOA and does not require synchronization between nodes. Multilateration is preferred as it eliminates the need for extra synchronization
IRJET- Study on Different Estimation Methods of Propulsion Power for 60 Mts O...IRJET Journal
This document studies different methods to estimate the propulsion power required for a 60-meter offshore supply vessel, including resistance calculation using Guldhammer & Harvald, Holtrop, and Oortmerssen methods. It analyzes the vessel's hull geometry and calculates parameters like resistance, effective power, and total resistance at ship speeds of 10-19 knots using each method. The results are compared to determine the most accurate way to obtain hull resistance and powering requirements for propelling the vessel.
1. The document outlines 23 performance standards that autopilot and heading control systems installed on ships must meet according to the International Maritime Organization (IMO).
2. The standards require systems to reliably maintain a preset heading under various operating conditions, incorporate controls to adjust for weather and steering performance, and allow for easy and safe operation.
3. Systems must also ensure the ship's heading can only be altered intentionally by crew, integrate properly with navigation systems, and include alarms and indications for failures or off-heading situations.
1. The purpose of a simplified voyage data recorder (S-VDR) is to securely store information about a vessel's position, movement, status, and command in the event of an incident for use in subsequent investigations.
2. Ships defined in SOLAS Chapter V must be fitted with an S-VDR that continuously records preselected data items relating to ship status, equipment output, and command/control. The data must be time-correlated and stored in a tamper-proof capsule for at least 2 years.
3. An S-VDR must record data items including date, time, position, speed, heading, bridge audio, communications audio, radar data, and AIS data
The document outlines 17 performance standards that GPS receiver equipment installed on ships must meet in order to be compliant. The standards require the equipment to:
1) Be capable of receiving and processing GPS signals to provide position, latitude and longitude, in the WGS-84 coordinate system and UTC time within specified accuracies and update rates.
2) Have static and dynamic position accuracy of 100m or less depending on whether differential GPS corrections are applied.
3) Generate and output position, course, speed, and time data at least once per second and interface with other navigation equipment.
4) Provide warnings if performance standards for position dilution or update rates are not met.
This document outlines the performance standards for echo-sounding equipment set by the International Maritime Organization (IMO). The equipment is intended to provide reliable depth readings between 2-200 meters to aid navigation, especially in shallow waters. It must have at least two depth ranges (20m and 200m scales), record soundings for 15 minutes, and be able to record depth and time for 12 hours. The display must show depth marks no more than 1/10 the range and time marks at most every 5 minutes. Alarms are required for shallow water and any failure affecting safe operation.
This document discusses an inclining test performed on a ship to determine its metacentric height (GM). It provides details of the test, including five shifts of weights totaling 216 tonnes that caused deflections of the ship ranging from 12 to 110 mm. It also shows the calculations to determine that the ship's GM as inclined is 1.68 m. Precautions for an accurate inclining test are noted, such as having a calm environment, securing loose weights, and restricting crew movement during the test.
The document discusses the relationships between a ship's speed, displacement, distance traveled, and fuel consumption. It states that daily fuel consumption varies as the cube of ship speed, as the 2/3 power of displacement, and as the square of speed multiplied by distance for a voyage. Examples are provided to demonstrate calculating new fuel consumption with changes in speed, displacement or distance. Specific fuel consumption is also defined as the fuel used per kilowatt hour of power.
An integrated bridge system (IBS) combines systems like the integrated navigation system (INS) to allow centralized monitoring and control of operations from the bridge like navigation, machinery control, safety, and security. An IBS provides benefits like enhanced decision making and workload reduction. Key components of an IBS include the navigation management system, alarm system, and conning display. Passage planning, position fixing, and track keeping can be automated if principles are followed, but overreliance on automation without watchkeeping can be dangerous. An IBS interconnects INS and other systems, while INS specifically combines navigational data and systems.
VDR is a marine recording device that functions like an aircraft's black box, recording critical ship data and communications to help investigators determine the cause of accidents. A VDR continuously records data from navigational equipment, alarms, and communications for at least 12 hours. This data is stored in a protective capsule that can withstand fire and deep water immersion. Accessing and analyzing VDR data after an incident allows for faster, more accurate investigations that help improve safety. VDR recordings have also assisted ship owners in assessing bridge team performance and identifying areas for improvement.
The document contains several numerical problems related to marine gyrocompasses. It provides solutions to problems involving calculating the tilt and direction of a gyroscope's spin axis (SA) given its initial position and the latitude, passage of time, or a later observed position. One question calculates the percentage change in the moment of inertia (MOI) of a gyroscope rotor if its mass increases by 20% and radius of gyration decreases by 20%.
This document contains checklists for various emergency situations that may occur on ships, such as general emergencies, abandoning ship, search and rescue, rescuing crew from a disabled vessel, flooding, fire, stranding or grounding, collision, main engine failure, steering failure, rudder failure, and checklists for navigation in coastal and ocean waters. The checklists provide step-by-step instructions for crew to follow to ensure passenger and crew safety, assess damage, send distress signals, and follow proper emergency procedures in a variety of emergency situations at sea.
1. Atmospheric pressure is the pressure exerted by the weight of the earth's atmosphere. It is measured in hectopascals (hPa), with 1 hPa equal to 1 millibar.
2. Pressure gradient refers to the rate of change of pressure over distance and indicates how strongly winds will blow between areas of high and low pressure.
3. Dew point temperature is the temperature at which air becomes saturated with water vapor and fog can form. It is an important measurement for mariners to consider when deciding whether to ventilate cargo holds.
1. The document outlines International Maritime Organization performance standards for Bridge Navigational Watch Alarm Systems (BNWAS).
2. BNWAS monitors bridge activity and detects if the Officer of the Watch becomes incapacitated, alerting others. It has automatic, manual on, and manual off operational modes.
3. The system remains dormant for 3-12 minutes before initiating visual alerts. If not reset, it issues audible alarms to the bridge and then remotely to summon help. Resetting cancels alerts and restarts the dormant period.
1. An electromagnetic (EM) log works by inducing an electromotive force in sea water moving through the Earth's magnetic field using a solenoid, with the induced voltage proportional to water velocity.
2. The solenoid is housed in a streamlined flow sensor that extends below the ship's hull. Electrodes on either side of the sensor measure the voltage induced in the strip of sea water moving across the magnetic field.
3. This voltage corresponds to ship speed and is amplified and used to drive indicators showing speed in the wheelhouse. The EM log thus non-intrusively measures ship speed through water.
1) A marine gyrocompass uses a freely-spinning gyroscope to determine direction based on the principles of angular momentum and the earth's constant rotation.
2) A gyroscope has three degrees of freedom - it can spin about its axis and tilt or turn in horizontal and vertical planes. The earth acts like a giant free gyroscope due to its mass, high-speed rotation, and lack of friction in space.
3) The gyroscope's angular momentum and inertia cause it to resist changes to its axis of spin, allowing it to maintain a fixed direction in space independent of the ship's movements. This gyroscopic property is used to determine true north.
1. The document outlines performance standards for route planning, monitoring, and voyage recording functions of Electronic Chart Display and Information Systems (ECDIS).
2. It describes that ECDIS should allow for simple and reliable route planning including straight and curved segments as well as adjustments to planned routes. It should monitor the ship's position along the selected route and provide alarms if deviations occur.
3. For voyage recording, ECDIS should store minimum navigation elements from the past 12 hours including ship track, time, position and headings as well as the ENC database information used for reconstruction and verification purposes. It should also record the complete voyage track with time marks not exceeding 4 hours.
1. The document outlines performance standards for Electronic Chart Display and Information Systems (ECDIS) as set by the International Maritime Organization (IMO).
2. The primary function of ECDIS is to contribute to safe navigation by displaying all necessary chart information and facilitating simple chart updating. ECDIS should reduce navigational workload compared to paper charts.
3. ECDIS must have reliability and availability equal to or better than paper charts, and provide alarms for information errors or equipment malfunctions. It must support on-board testing and back-up arrangements to ensure safe navigation if ECDIS fails.
This document outlines performance standards for electronic chart display and information systems (ECDIS) regarding displays. It includes standards for the display of electronic navigational chart (SENC) information such as displaying the standard display at the largest scale by a single operator action. It also covers displaying navigational information like radar in a way that does not degrade the SENC information. Additional standards address display mode in north-up orientation, true motion mode, and the generation of neighboring areas. Minimum display requirements like an effective chart size of 270mm by 270mm are also specified.
VDR is a marine recording device similar to an aircraft's black box. It records critical ship parameters and operations data to help investigators determine the cause of accidents. A VDR consists of microphones, a main unit that receives and stores data, a power supply, and a voyage data capsule that stores the last 12 hours of data. The capsule is designed to withstand impacts, fire, and deep water pressure. VDR data can help make accident investigations faster and more accurate by providing an objective account of events. Ship owners retain ownership of VDR data but investigators have custody during investigations.
The document discusses the Long Range Identification and Tracking (LRIT) system. Key points:
- LRIT allows governments to track ships on a global scale and obtain position reports from ships flying their flag, entering their ports, or within 1000 nautical miles of their coast.
- It is mandated by the International Convention for the Safety of Life at Sea (SOLAS) for passenger ships, cargo ships over 300 gross tonnage, and mobile offshore drilling units on international voyages.
- The LRIT system involves shipborne transmitting equipment, communication providers, data centers, and an international data exchange to disseminate identity, position, and timestamp information to contracting governments and search and rescue services.
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...Scintica Instrumentation
Targeting Hsp90 and its pathogen Orthologs with Tethered Inhibitors as a Diagnostic and Therapeutic Strategy for cancer and infectious diseases with Dr. Timothy Haystead.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
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Q. Why are GPS satellites positioned in orbits 20,200 km above earth’s surface?
A. This height of orbits falls within range of orbit heights classified as medium earth orbits. This
height is chosen for GPS satellites for following reasons:
1. Footprint of satellites is large enough to provide global coverage,
2. Because of larger footprints of satellites, the total number of satellites is lesser than would be
needed if satellites were to orbit at lower heights,
3. This height is low enough for earth based transmitters/receivers to have modest sized antennas
and use lower transmission powers for the system to be used effectively.
Q. What is the difference between gross tonnage and net tonnage?
A. Tonnage in general refers to capacity or size of a ship.
Gross tonnage is a function of volume of enclosed spaces of a ship. It is indicative of ship’s size.
Net tonnage refers to volume of cargo carrying spaces. It is indicative of vessel’s earning potential.
The NT cannot be less than 30% of the GT of a ship. Net tonnage is used for ship’s dues.
Both GT and NT are determined by measuring ship’s volume and then applying a mathematical
formula. Both GT and NT are dimensionless numbers and are shown in ship’s International
Tonnage Certificate. They do not have any physical units and should not be confused with unit of
mass, namely ton.
Q. What do you understand by GRT and NRT?
A. GRT stands for Gross Register Tonnage and NRT means NET Register Tonnage. Both these
terms are now obsolete and have been replaced respectively with GT and NT under International
Convention on Tonnage Measurements of Ships.
However, students may note the definitions of GRT and NRT for their reference:
Gross Register Tonnage (GRT) meant a measure of the total internal capacity of the ship. It
consisted of: under-deck volume excluding double-bottoms, volume of tween deck spaces, volume
of superstructures, volume of deck-houses etc. Spaces like navigational areas, galleys, stairways,
light and air spaces were exempted. The total volume thus calculated in cubic feet was divided by
100 (1 gross ton = 100 cubic feet). This was the Gross Tonnage entered in the ship's Register.
Net Register Tonnage (NRT) meant a measure of the available space for the carriage of cargo
and passengers. This was obtained from GRT after making some deductions. These deductions
from GRT included: Master and crew accommodation, safety and storage spaces, water ballast
tanks, allowance for propelling machinery. Again the resulting volume in cubic feet was divided
by 100 (1 net ton = 100 cubic feet). This was the Net Tonnage entered in the Register.
Q. Which radar should be used for long range scanning?
A. 10 cm or S-band radar is better for long range scanning.
Q. Which radar should be used in heavy rain?
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A. 10 cm or S-band radar should be definitely on and used in rain, because 10 cm radar gives less
rain clutter. However, in situations like this, it is preferable to keep both radars on and use the
advantage of 10 cm radar accordingly.
Q. How will you ascertain the performance of your radar?
A. The performance of radar can be ascertained with the help of performance monitor.
Q. What is parallel indexing and what is its principle?
A. Parallel indexing is a technique of executing and monitoring ship’s motion along a pre-
determined charted track. While keeping the radar screen under observation it provides instantly
ship’s position with respect to the charted track. It fills the gap between two consecutive plotted
positions and allows for the off-track deviation to be treated well in time. Though the technique is
termed as continuous fixing, it does not absolve OOW of duties of fixing vessel’s position at
regular intervals.
Parallel indexing works on the principle of relative motion, in which the echo of a ground-based
(fixed) target moves across radar display at a speed and in direction which is exact reciprocal of
ship’s motion over ground. The target chosen should be isolated, radar-conspicuous and positively
identified.
Q. Which mode of radar motion should be used for parallel indexing?
A. Both relative motion (RM) and true motion (TM) are equally suitable for parallel indexing.
Q. Radars are interfaced with speed logs as well as GPS. GPS gives SOG, while log is intended to
provide STW. How will you decide which speed to use and when?
A. I will use STW for applying ROR i.e. for taking decisions on collision avoidance. This means to
say that my radar will be switched to STW mode, when at sea.
But, SOG also has its own functions. It is very useful, because it shows the CMG vector as well on
radar screen. So I can use SOG mode when navigating in restricted waters dotted with shoals,
islets, rocks etc. and also while negotiating turns in proximity of hazards.
Q. There is some interface trouble between your radar and speed log and you are unable to get the
STW input on radar. What will you do?
A. I will enter the STW manually by using the manual option on radar and navigate accordingly.
Q. What do you understand by EPA and ATA?
A. Both EPA and ATA are radar plotting aids. EPA stands for electronic plotting aid and ATA
stands for automatic tracking aid.
Q. How are they different from each other?
A. In EPA each target needs to be plotted manually and EPA gives target data for each manual
plot. It is the simplest form of advancement in automation, in which the triangle OAW is solved
electronically. EPA is required to be fitted on all ships of 300 GT and upwards and passenger ships
irrespective of size.
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In ATA target is acquired manually and plotting is automatic. This is the next step ahead where
target once acquired manually is tracked automatically. All ships of 500 GT and above are required
to be fitted with ATA.
Q. What are the minimum parameters of a radar plot?
A. The seven minimum parameters are:
Target identity, bearing, distance, CPA, TCPA, target course and target speed.
Q. Is there any other type of plotting aid?
A. Yes. It is known as automatic radar plotting aid (ARPA) and it is required to fitted on all ships
of 10,000 GT and above.
Q. As a cadet you have sailed on ships upwards of 10,000 GT. You are about to join as 3rd
mate a
ship whose GT is less than 10,000 and it is not fitted with ARPA. What does it mean to you as an
OOW?
A. It means that the ship will be fitted with ATA. I will be aware of the limitations of ATA as
compared to ARPA. ATA does not provide functions like automatic acquisition and plotting of at
least 20 targets, trial maneuver etc. available on any ARPA. I will make myself fully familiar with
these limitations and operational procedures by referring to the operator’s manual and carry out
navigational duties accordingly.
Q. What are the two additional navigational equipments required to be fitted on ships of 50,000
GT and upwards?
A. They are:
1. Rate of turn indicator (ROTI) to determine and indicate the rate of turn for facilitating the
execution of curved segments of planned passage.
2. Speed and distance measuring equipment to determine and indicate speed of ship over ground
(SOG) in the forward and athwartships direction. This requirement is usually met by fitting
Doppler speed log.
Q. What do you understand by wind rose?
A. Wind rose is graphical depiction of wind data as regard to direction and force of wind likely to
be encountered in an area, in a particular period or month. With the help of the wind rose, it can be
known at a glance the likelihood of encountering wind from a particular direction at a given force.
Wind roses are shown in red on routeing charts, in the form of a circle having arrows pointing
radially towards centre. The arrows fly with the wind and this fact provides the direction. The
length of the arrow indicates the percentage frequency of occurrence on the scale provided on the
chart (2inches equal 100%). The thickness of the arrow indicates the wind force. The arrows cross
the circle by an amount which equals 5% frequency and provides a quick estimation.
The circle also encloses three figures placed one above the other. The top figure represents the total
number of observations. Middle figure represents the %age frequency of variable winds
encountered. And, the bottom figure is indicative of %age frequency of calms.
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.
Wind rose as shown on a routeing chart
Q. What is fog detector light?
A. Fog detector light is a light which is fitted on structure of light station. It may, however, be
fitted some distance away from the station. Fog detector light detects fog and switches on fog
signals automatically. It may also transmit the range of visibility to a data center, which in turn
broadcasts the information to mariners. Fog detector lights operate both by day and night.
Q. What is the difference between ‘aid to navigation’ and ‘navigational aid’?
A. ‘Aid to navigation’ is a mechanism or arrangement designed, established and operated
externally to ship in order to enhance navigational safety of marine traffic. For example: beacons,
buoys, light houses, leading lights etc.
‘Navigational aid’ means a gadget, instrument or equipment internal to ship and is intended to
assist navigation. For example: echo sounder, radar, AIS, chart, compass etc.
Q. What kind of information is available from routeing charts?
A. Routeing charts provide following categories of information and play significant role in passage
planning:
1. Wind direction, strength and probability of encountering (%age frequency) same in a particular
area. This is done in the form of wind roses. Wind rose also gives %age frequency of variable
winds and calm seas.
2. Direction and strength of sea currents with %age constancy in quadrants and octants.
3. Shipping routes and distances in nautical miles between ports.
4. Mean air pressure
5. Mean air temperature
6. Mean sea water temperature
7. Mean dew point temperature
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8. Percentage frequency of fog occurrence (visibility < 0.5 M)
9. Percentage frequency of low visibility (visibility < 5.0 M)
10.Percentage frequency of winds of force 7 and above
11.Selected tracks of TRS experienced in the past years in the area
12.ILL zones
13.Ice limits
Q. What is the difference between ‘observation spot’ and benchmark?
A. Observation spot represents a position on chart, where accurate astronomical observations have
been made to obtain latitude and longitude. On charts, it is shown as:
Benchmark is a mark the height of which above a known datum is accurately and exactly known. It
may consist of bolt head or a rivet fitted into concrete or an arrow mark cut into masonry.
On charts, it is shown as:
Q. What is the difference between rectilinear stream and rotary stream?
A. Rectilinear stream is that type of tidal stream which travels almost in straight line alternately in
opposing directions separated by a period of slack water.
Rotary stream is that tidal stream whose direction changes gradually through 3600
completing a tidal cycle.
The change in direction may be in clockwise or counter clockwise direction.
Q. Compare pebbles cobbles and boulders?
A. All three are water rounded stones and are named according to their respective sizes as follows:
Pebbles: 4 mm – 64 mm
Cobbles: 64 mm – 256 mm
Boulders: > 256 mm
Q. What do you understand by ‘situational awareness’?
A. Situational awareness comprises three components in a situation:
a. Perception (hearing, seeing, feeling etc.) of technical and/or navigational information available to
OOW.
b. Understanding unambiguously the meaning of such information.
c. Development of the present status in the near future and the adequate preparedness for the effective
handling of the development.
Q. In the context of ECDIS, BNWAS etc., what do you understand by ‘single operator action’?
A. ‘Single operator action’ means procedure attained by ONLY one hard-key or soft-key action. There is
no involvement of any voice actuation using programmed codes or cursor movements.
Q. Why is moon not used for taking amplitude?
A. Amplitude is taken at the time of geometric rise or set of a celestial body. This occurs when the centre
of body coincides with rational horizon. However, all the bodies except the moon appear well above the
horizon due to the influence of refraction.
6. 6 | P a g e O r a l s N a v i g a t i o n a n d W a t c h k e e p i n g
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Refraction elevates the moon as well, but this effect is outweighed by the depressing effect of horizontal
parallax. As a result moon remains invisible at the time of its geometric rise or set and its amplitude cannot
be calculated.
Q. What is the objective and importance of day light signaling lamp?
A. The objective of day light signaling lamp is to ensure, in suitable and reliable manner, conveyance of
information between ships or between ship and shore by light signals, both by day and night.
Carriage of day light signaling lamp is important for safety reasons. It is necessary for signaling in different
situations as required by:
COLREGS
IAMSAR and
International Code of Signals
Q. What is the least visibility of light emitted by day light signaling lamp, under normal atmospheric
conditions?
A. Two nautical miles.
Q. What are the power requirements for the signaling lamp?
A. The signaling lamp is not to be dependent only on ship’s main or emergency supply of electricity. In
addition, it should be provided with a portable battery having sufficient capacity to ensure the lamp’s
operation for a period of not less than 2 hours.
Q. What are the requirements of day light signaling lamp’s bulb?
A. The lamp should be designed such as will allow the replacement of bulb even in dark. The use of
screwed sockets should be avoided.
At least three spare type-approved bulbs are required to be provided with the signaling lamp.