With few exceptions – such as in traffic separation zones or restricted areas – ships are generally free to choose their own route from port of departure to port of destination. Tankers and ships carrying hazardous cargoes will be more restricted. However, when it comes to ships subject to SOLAS rules (and any other craft the flag state decides) there is a requirement under SOLAS Chapter V Regulation 34 for a passage plan to be prepared for the voyage.
The actual wording of Regulation 34 is; “Prior to proceeding to sea, the master shall ensure that the intended voyage has been planned using the appropriate nautical charts and nautical publications for the area concerned, taking into account the guidelines and recommendations developed by the Organization” (Resolution A.893(21)).
It goes on to say;
The voyage plan shall identify a route which:
- takes into account any relevant ships’ routeing systems
- ensures sufficient sea room for the safe passage of the ship throughout the voyage
- anticipates all known navigational hazards and adverse weather conditions; and
- takes into account the marine environmental protection measures that apply, and avoids, as far as possible, actions and activities which could cause damage to the environment
Poor or non-existent passage planning is the fifth highest cause for PSC detentions according to figures from the Paris MoU.
A passage plan can be prepared in one of two ways – conventionally using paper charts and publications or electronically using an ECDIS or specialist software products such as NAVTOR’s NavStation which can also be supplied as a digital chart table. Typically, a passage plan will be produced by the Second Officer on most ships but could be prepared by another senior officer and in either case should be signed off by the Master.
Passage planning is a process that requires skill and meticulous research. It is not something that should be taken lightly as it carries responsibility and the consequences of getting it wrong are serious. It can be time consuming especially if done conventionally and the voyage is long or involves navigation through hazardous waters. When done properly, a plan done using paper charts can take several hours to rough out, check and produce.
Having decided upon a basic route, the navigator must check that all of the charts covering the route in various scales are available on board and have been updated and corrected using all relevant tracings and Notice to Mariners. Using the updated charts, Pilot books, tide tables and atlases, lists of lights and fog signals, sailing directions, weather forecasts and many other sources of information the navigator will refine the route making particular notes of any hazards that will be encountered and detailing contingencies.
Whether a route is safe or not depends also on the draught and trim of the ship which can change as bunkers are consumed or taken on board, the type of cargo, the ship’s manoeuvring characteristics just as much as the route itself. If the ship is on time charter and the charterer has been allowed to instruct the ship to use a third-party routeing service, then the proposed route should also be checked and not blindly accepted.
The passage plan is not merely a paper exercise, details of the route and actions to be taken under changing circumstances are all recorded as part of the plan. It should include details of any hazards that might be encountered such as adverse currents and winds, precise locations of any rocks or wrecks that need to be avoided and even where security threats are likely to occur. The ship may have standing orders for the Master to be informed when particular situations arise or when the ship is approaching a particular place where for safety reasons it is deemed necessary to have a larger bridge team present.
Once underway the plan should be followed and monitored constantly so that course changes occur at the designated waypoints (or more specifically at the wheel over point needed to make the turn depending upon ship speed etc) and any deviation should only be permitted with the authorisation of the master. When navigating using paper charts, it is good practice to have the chart covering the vessel’s present position on the chart table so that in an emergency all relevant information is to hand.
In a modern ship practising e-navigation, the passage planning is made easier in some respects but it would not be sufficient just to expect to enter departure and arrival ports, basic ship information and draught and expect the ECDIS or specialist software to do all the calculations and produce a detailed passage plan. The navigator still needs to mark the course, enter waypoints, set parameters and mark no go areas, mark abort points and point of no return just as with paper charts. The software will highlight any critical points and the navigator should examine these carefully making changes to the route as necessary.
Although some models of ECDIS can be used for passage planning purposes, a more sophisticated answer is the NAVTOR digital chart table with its latest NavStation software version. Whereas the ECDIS screen is relatively small compared to a typical chart table, NAVTOR’s digital table has a 46” tabletop screen that can be overlaid in the same way as ECDIS can and give access to all of the electronic publications and other detail used during conventional passage planning.
The same software that is used in the digital table can be used on an ordinary computer, but the size of the chart table means working with it combines the best practices of conventional and e-navigation to be combined. With the NavStation digital chart table, the base layer is the appropriate ENC on which several layers can be overlaid. These cover such things as Admiralty digital publications, notices to mariners and digital versions of all of the other sources used for traditional passage planning.
Being able to zoom in and out on screens means that the switching between charts of different scales can be done without physically bringing more charts to the chart table. The size of the digital table – in comparison to an ECDIS – also allows routes to be compared using a split screen function. When satisfied, the navigator saves the route and prints out the passage plan for authorisation and use during the voyage. It will also be transferred to the ECDIS.
With conventional passage planning, any instruction to take specific action at a given point or time could be overlooked and lead to a hazardous situation occurring. Although an ECDIS and other e-navigation equipment can be programmed to sound alarms at such times there are mistakes made that are unique to ships practising e-navigation and it would be foolish not to recognise this. But then in in the 1950’s when radar was first installed on commercial ships there were cases of ‘radar assisted collisions’ but no navigator today would say that radar is not an essential.
There are two main reasons why ECDIS assisted incidents occur; one is poor training and incorrect use of the equipment and the other is over-reliance on the equipment and a belief that it is infallible. Neither of these has an easy solution but both could be addressed and the risk of the first reason minimised through use of shore centres where ships can be monitored in real time and information sharing allowing a second (or more) pairs of eyes to check for errors.
ECDIS and other software can undoubtedly perform the calculations quicker than most humans when checking a route for under keel clearances and the distance from areas to be avoided, but if those basic parameters have been inputted incorrectly, the machine may not recognise the fact. It should also be recognised by navigators that despite the confidence that an ECDIS can give because it is interactive and passage plans can be run through and checked, both paper charts and ENCs currently use precisely the same information. That information may be based on hydrographic surveys that took places long in the past. Reliability of hydrographic surveys can be observed in the CATZOC’s that are in the ENC cells (have to be activated in the chart portrayal settings)
As well as safety measures that need to be considered, modern passage planning also requires that environmental limitations may apply. These can relate to matters as diverse as where ballast water exchange is permitted, use of open-loop scrubbers restricted, fuel change over for entering an ECA, disposal of black water or garbage and more. Keeping track of all of these is as important as chart updating if penalties are to be avoided. Overlays of environmental information on NAVTOR’s NavStation is possible using an appropriate subscription service if an owner chooses.