Radars and Parallel Index Lines

31st October 2006

Radars and Parallel Index Lines

Initial Report

Report Text:

Some radars, although type tested have a severe navigational limitation that I have observed, which I wish to bring to your attention.

I encounter a wide range of radars with very little opportunity to familiarise myself with their operation before I am using them in earnest. I receive regular radar updating training and know what I want a radar to do, but increasingly, I am unable to do so due the complexity of different knobs and menus that are used by all the various radar manufacturers.

The perception amongst ‘armchair critics’ is that parallel indexing techniques (PI) are employed at all times irrespective of the visibility. I find that on a large number of radar installations that I come across it is increasingly difficult, if not near impossible, to simply set up a PI. I note that when I refer the problem to the Navigating Officer or Master, they more often than not, also struggle as well.

There is clearly a mismatch between the perception of what navigators are required to do and what is actually achievable. Current type testing has not kept pace with the technical innovations that are being applied by software engineers and embraced by the marketing department.

I have been using marine radars professionally for many years and whilst there have been some considerable overall improvements, there is now too much complexity presented by all the numerous radar manufacturers and little uniformity that would help mariners use the equipment easily and safely. Conversely, airline pilots who are type tested to fly certain aircraft will find that each cockpit they encounter is the same as the last, which gives an ‘intuitive’ feel to the use of all the equipment – something that due to poor design is alien to the mariner!

CHIRP Comment:

Parallel Indexing (PI) is a simple and highly effective navigational technique for monitoring a vessel’s track and all navigating officers should be able to use it as a fundamental skill.  If difficulties are experienced in setting a PI up on particular radar types this should be reported through your Safety Management System, so manufacturers may be informed.

There have been a number of accidents in the past; such as the “Exxon Valdez”, where the use of PI may have provided early warning of danger.  It is a matter of concern to the Maritime Advisory Board that some radar equipment may not facilitate the use of this technique.

This report was accompanied by a detailed study of several radar types detailing the steps required to set up a PI and outlining the difficulties experienced. The report and attachments have been sent to the Nautical Institute for discussion with the International Electrotechnical Commission (IEC) and also to the Maritime Ergonomics Special Interest Group (MarESIG).  MarESIG have published the issue on www.maresig.org.

The recently published CHIRP report on Marine Operating & Maintenance Manuals addresses the complexity of navigational systems in part and suggests standard document formats have a role to play in promoting efficient familiarisation and operation of equipment, however there is also an argument for specifying and prioritising basic functionality such as PI.

Design and operational issues such as these are important and CHIRP is well placed to bring these issues to the attention of those in a position to do something about them.  Many manufacturers are keen to learn from end users, so if you want your voice to be heard, CHIRP!


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