December 12, 2010
Records
Ensure the following records are assembled and personnel assigned to maintain them:? Bearing Record Book: The bearing recorders for the primary and secondary plots should record all the bearings used on their plot during the entire transit.
The books should clearly list what NAVAIDS are being used and what method of navigation was being used on their plot. In practice, the primary bearing book will contain mostly visual bearings and the secondary bearing book will contain mostly radar ranges and bearings.
? Fathometer Log: In restricted waters, monitor soundings continuously and record soundings every five minutes in the fathometer log. Record all fathometer settings that could affect the sounding display.
? Deck Log: This log is the legal record of the passage.
Record all ordered course and speed changes. Record all the navigator recommendations and whether the navigator concurs with the actions of the conning officer.
Record all buoys passed, and the shift between different Rules of the Road. Record the name and embarkation of any pilot. Record who has the conn at all times. Record any casualty or important event. The deck log combined with the bearing log should constitute a complete record of the passage.
Tides and CurrentsDetermining the tidal and current conditions of the port is crucial. This process is covered in depth in Chapter 9. In order to anticipate early or late transit, plot a graph of the tidal range for the 24-hour period centered on the scheduled time of arrival or departure. Depending on a vessel draft and the harbor depth, some vessels may be able to transit only at high tide. If this is this case, it is critically important to determine the time and range of the tide correctly.
The magnitude and direction of the current will give the navigator some idea of ??the set and drift the vessel will experience during the transit. This will allow him to plan in advance for any potential current effects in the vicinity of navigational hazards.
While printed tide tables can be used for predicting and plotting tides, it is far more efficient to use a computer with appropriate software, or the internet, to compute tides and print out the graphs. These graphs can be posted on the bridge at the chart table for ready reference, and copies made for others involved in the piloting process. Always remember that tide tables give predicted data, but that actual conditions may be quite different due to weather or other natural phenomena.
WeatherThe navigator should obtain a weather report covering the route which he intends to transit. This will allow him to prepare for any adverse weather by stationing extra lookouts, adjusting speed for poor visibility, and preparing for radar navigation. If the weather is thick, consider standing off the harbor until it clears.
The navigator can receive weather information any number of ways. Military vessels may receive weather reports from their parent squadrons prior to coming into port. Marine band radio carries continuous weather reports.
Many vessels are equipped with weather facsimile machines. Some navigators carry cellular phones to reach shoreside personnel and harbor control; these can also be used to get weather reports from NOAA weather stations. If the ship is using a weather routing service for the voyage, it should provide forecasts when asked. Finally, if the vessel has an internet connection, this is an ideal source of weather data. However he obtains the information, the navigator should have a good idea of ??the weather before entering piloting waters.
The Piloting BriefAssemble the entire navigation team for a piloting brief prior to entering or leaving port. The vessel captain and navigator should conduct the briefing. All navigation and bridge personnel should attend. The pilot , if he is already on board, should also attend. If the pilot is not onboard when the ship company is briefed, the navigator should immediately brief him when he embarks. The pilot must know the ship maneuvering characteristics before entering restricted waters. The briefing should cover, as a minimum, the following:
? Detailed Coverage of the Track Plan: Go over the planned route in detail. Use the prepared and approved chart as part of this brief. Concentrate especially on all the NAVAIDS and soundings which are being used to indicate danger. Cover the buoyage system in use and the port major NAVAIDS. Point out the radar NAVAIDS for the radar operator. Often, a Fleet Guide or Sailing Directions will have pictures of a port NAVAIDS. This is especially important for the piloting party that has never transited a particular port before. If no pictures are available, consider stationing a photographer to take some for submission to NIMA.
? Harbor Communications: Discuss the bridge -to bridge radio frequencies used to raise harbor control.
Discuss what channel the vessel is supposed to monitor on its passage into port and the port communication protocol.
? Duties and Responsibilities: Each member of the piloting team must have a thorough understanding of his duties and responsibilities. He must also understand how his part fits into the whole. The radar plotter, for example, must know if radar will be the primary or secondary source of fix information. The bearing recorder must know what fix interval the navigator is planning to use. Each person must be thoroughly briefed on his job; there is little time for questions once the vessel enters the channel.
Evolutions Prior to Piloting
The navigator should always accomplish the following evolutions prior to piloting:
? Testing the Shaft on the Main Engines in the Astern Direction: This ensures that the ship can answer a backing bell. If the ship is entering port, no special precautions are required prior to this test. If the ship is tied up at the pier preparing to get underway, exercise extreme caution to ensure no way is placed on the ship while testing the main engines.
? Making the Anchor Ready for Letting Go: Make the anchor ready for letting go and station a watchstander in direct communications with the bridge at the anchor windlass. Be prepared to drop anchor immediately when piloting if required to keep from drifting too close to a navigational hazard.
? Calculate Gyro Error: An error of greater than 1.0 ° T indicates a gyro problem which should be investigated prior to piloting. There are several ways to determine gyro error: 1. Compare the gyro reading with a known accurate heading reference such as an inertial navigator. The difference in the readings is the gyro error.
2. Mark the bearing of a charted range as the range NAVAID come into line and compare the gyro bearing with the charted bearing. The difference is the gyro error.
3. Prior to getting underway, plot a dockside fix using at least three lines of position. The three LOP should intersect at a point. Their intersecting in a “cocked hat” indicates a gyro error. Incrementally adjust each visual bearing by the same amount and direction until the fix plots as a pinpoint. The total correction required to eliminate the cocked hat is the gyro error.
4. Measure a celestial body azimuth or amplitude, or Polaris azimuth with the gyro, and then compare the measured value with a value computed from the Sight Reduction Tables or the Nautical Almanac.
Report the magnitude and direction of the gyro error to the navigator and captain. The direction of the error is determined by the relative magnitude of the gyro reading and the value against which it is compared. When the compass is least, the error is east. Conversely, when the compass is best, the error is west. See Chapter 6.
Inbound Voyage Planning
The vessel planned estimated time of arrival (ETA) at its mooring determines the vessel course and speed to the harbor entrance. Arriving at the mooring site on time may be important in a busy port which operates its port services on a tight schedule. Therefore, it is important to plan the arrival accurately. Take the desired time of arrival at the mooring and subtract from that the time it will take to navigate to it from the entrance. The resulting time is when you must arrive at the harbor entrance. Next, measure the distance between the vessel present location and the harbor entrance. Determine the speed of advance (SOA) the vessel will use to make the transit to the harbor. Use the distance to the harbor and the SOA to calculate what time to leave the present position to make the mooring ETA, or what speed must be made good to arrive on time.
Consider these factors which might affect this decision:
? Weather: This is the single most important factor in harbor approach planning because it directly affects the vessel SOA. The thicker the weather, the more slowly the vessel must proceed. Therefore, if heavy fog or rain is in the forecast, the navigator must allow more time for the transit.
? Mooring Procedures: The navigator must take more than distance into account when calculating how long it will take him to pilot to his mooring. If the vessel needs a tug, that will increase the time needed. Similarly, picking up or dropping off a pilot adds time to the transit. It is better to allow a margin for error when trying to add up all the time delays caused by these procedures. It is always easier to avoid arriving early by slowing down than it is to make up lost time by speeding up.
? Shipping Density: Generally, the higher the shipping density entering and exiting the harbor, the longer it will take to proceed into the harbor entrance safely.
TRANSITION TO PILOTING
Stationing the Piloting Team
At the appropriate time, station the piloting team. Allow plenty of time to acclimate to the navigational situation and if at night, to the darkness. The number and type of personnel available for the piloting team depend on the vessel. A Navy warship, for example, has more people available for piloting than a merchant ship. Therefore, more than one of the jobs listed below may have to be filled by a single person. The piloting team should consist of:
? The Captain: The captain is ultimately responsible for the safe navigation of his vessel. His judgment regarding navigation is final. The piloting team acts to support the captain, advising him so he can make informed decisions on handling his vessel.
? The Pilot: The pilot is usually the only member of the piloting team not a member of the ship company. The piloting team must understand the relationship between the pilot and the captain. The pilot is perhaps the captain most important navigational advisor.
Generally, the captain will follow his recommendations when navigating an unfamiliar harbor. The pilot, too, bears some responsibility for the safe passage of the vessel; he can be censured for errors of judgment which cause accidents. However, the presence of a pilot in no way relieves the captain of his ultimate responsibility for safe navigation. The piloting team works to support and advise the captain.
? The Officer of the Deck (Conning Officer): In Navy piloting teams, neither the pilot or the captain usually has the conn. The officer having the conn directs the ship movements by rudder and engine orders.
Another officer of the ship company usually fulfills this function. The captain can take the conn immediately simply by issuing an order to the helm should an emergency arise. The conning officer of a merchant vessel can be either the pilot, the captain, or another watch officer. In any event, the officer having the conn must be clearly indicated in the ship deck log at all times. Often a single officer will have the deck and the conn. However, sometimes a junior officer will take the conn for training. In this case, different officers will have the deck and the conn. The officer who retains the deck retains the responsibility for the vessel safe navigation.
< br />? The Navigator: The vessel navigator is the officer directly responsible to the ship captain for the safe navigation of the ship. He is the captain principal navigational advisor. The piloting team works for him.
He channels the required information developed by the piloting team to the ship conning officer on recommended courses, speeds, and turns. He also carefully looks ahead for potential navigational hazards and makes appropriate recommendations. He is the most senior officer who devotes his effort exclusively to monitoring the navigation picture. The captain and the conning officer are concerned with all aspects of the passage, including contact avoidance and other necessary ship evolutions (making up tugs, maneuvering alongside a small boat for personnel transfers, engineering evolutions, and coordinating with harbor control via radio, for example). The navigator, on the other hand, focuses solely on safe navigation. It is his job to anticipate dangers, keep himself appraised of the navigation situation at all times, and manage the team.
< br />? Bearing Plotting Team: This team consists, ideally, of three persons. The first person measures the bearings. The second person records the bearings in an official record book. The third person plots the bearings. The more quickly and accurately this process is completed, the sooner the navigator has an accurate picture of the ship position. The bearing taker should be an experienced individual who has traversed the port before and who is familiar with the NAVAIDS.
He should take his round of bearings as quickly as possible, beam bearings first, minimizing any time delay errors in the resulting fix. The plotter should also be an experienced individual who can quickly and accurately lay down the required bearings. The bearing recorder can be one of the junior members of the piloting team.
? The Radar Operator: The radar operator has one of the more difficult jobs of the team. The radar is as important for collision avoidance as it is for navigation. Therefore, this operator must often “time share” the radar between these two functions.
Determining the amount of time spent on these functions falls within the judgment of the captain and the navigator. If the day is clear and the traffic heavy, the captain may want to use the radar mostly for collision avoidance. As the weather worsens, obscuring visual NAVAIDS, the importance of radar for safe navigation increases. The radar operator must be given clear guidance on how the captain and navigator want the radar to be operated.
? Plot Supervisors: On many military ships, the piloting team will consist of two plots: the primary plot and the secondary plot. The navigator should designate the type of navigation that will be employed on the primary plot.
All other fix sources should be plotted on the secondary plot. The navigator can function as the primary plot supervisor. A senior, experienced individual should be employed as a secondary plot supervisor. The navigator should frequently compare the positions plotted on both plots as a check on the primary plot.
There are three major reasons for maintaining a primary and secondary plot. First, as mentioned above, the secondary fix sources provide a good check on the accuracy of visual piloting. Large discrepancies between visual and radar positions may point out a problem with the visual fixes that the navigator might not otherwise suspect. Secondly, the navigator often must change the primary means of navigation during the transit . He may initially designate visual bearings as the primary fix method only to have a sudden storm or fog obscure the visual NAVAIDS. If he shifts the primary fix means to radar, he has a track history of the correlation between radar and visual fixes. Finally , the piloting team often must shift charts several times during the transit. When the old chart is taken off the plotting table and before the new chart is secured, there is a period of time when no chart is in use.
< br /> Maintaining a secondary plot eliminates this complication.
Ensure the secondary plot is not shifted prior to getting the new primary plot chart down on the chart table. In this case, there will always be a chart available on which to pilot. Do not consider the primary chart shifted until the new chart is properly secured and the plotter has transferred the last fix from the original chart onto the new chart.
? Satellite Navigation Operator: This operator normally works for the secondary plot supervisor. GPS accuracy with Selective Availability (SA) on is not sufficient for navigating restricted waters; but with SA off, GPS can support harbor navigation, in which case it should be considered as only one aid to navigation, not as a substitute for the entire process. If the team loses visual bearings in the channel and no radar NAVAIDS are available, GPS may be the most accurate fix source available. The navigator must have some data on the comparison between satellite positions and visual positions over the history of the passage to use satellite positions effectively. The only way to obtain this data is to plot satellite positions and compare these positions to visual positions throughout the harbor passage.
? Fathometer Operator: Run the fathometer continuously and station an operator to monitor it. Do not rely on audible alarms to key your attention to this critically important piloting tool. The fathometer operator must know the warning and danger soundings for the area the vessel is transiting. Most fathometers can display either total depth of water or depth under the keel. Set the fathometer to display depth under the keel. The navigator must check the sounding at each fix and compare that value to the charted sounding. A discrepancy between these values ??is cause for immediate action to take another fix and check the ship position.
Harbor Approach (Inbound Vessels Only)
The piloting team must make the transition from coastal navigation to piloting smoothly as the vessel approaches restricted waters. There is no rigid demarcation between coastal navigation and piloting. Often visual NAVAIDS are visible miles from shore where Loran and GPS are easier to use. The navigator should take advantage of this overlap when approaching the harbor. Plotting Loran, GPS, and visual fixes concurrently ensures that the piloting team has correctly identified NAVAIDS and that the different types of systems are in agreement. Once the vessel is close enough to the shore such that sufficient NAVAIDS (at least three with sufficient bearing spread) become visible, the navigator should order visual bearings only for the primary plot and shift all other fixes to the secondary plot, unless the decision has been made to proceed with ECDIS as the primary system.
Take advantage of the coastal navigation and piloting overlap to shorten the fix interval gradually. The navigator must use his judgment in adjusting fix intervals. If the ship is steaming inbound directly towards the shore, set a fix interval such that two fix intervals lie between the vessel and the nearest danger. Upon entering restricted waters, the piloting team should be plotting visual fixes at three minute intervals.
Commercial vessels with GPS and / or Loran C, planning the harbor transit with a pilot, will approach a coast differently. The transition from ocean to coastal to harbor approach navigation will proceed as visual aids and radar targets appear and are plotted. With GPS or ECDIS operating and a waypoint set at the pilot station, only a few fixes are necessary to verify that the GPS position is correct. Once the pilot is aboard, the captain / pilot team may elect to navigate visually, depending on the situation.