Proceedings Of The Marine

SUM 2015

Proceedings magazine is a communication tool for the Coast Guard's Marine Safety & Security Council. Each quarterly magazine focuses on a specific theme of interest to the marine industry.

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59 Summer 2015 Proceedings For example, navigators must know the components of reporting interval, GPS antenna position, or even GPS fail- ure represent to AIS operation when combined with other electronic navigation aids. The navigator must also under- stand the various AIS sensors and be aware that inaccurate input and/or upkeep of AIS data felds will result in errone- ous information. That said, adding AIS to a navigational aid, such as a buoy, dramatically increases the amount of information available on a charted object. One single ATON can confrm what is seen out the window with three forms of electronic identi- fcation (radar return, RACON, and AIS) on the radar, and positional identifcation (AIS ATON symbol) overlaid on an ECS/ECDIS. While this corroboration can certainly be viewed as a beneft, training must reinforce avoiding fxat- ing on single sources of information. AIS Virtual ATONs Virtual ATONs are digital information objects that do not physically exist, but can be used to mark recent hazards or VTS call-in points, or can be placed in areas that have environmental or operational requirements. They enhance safety by providing timely notifcation and information on a screen that is visually apparent to the navigator. However, radar and some ECDIS might not display AIS ATONs, and even then, their display may vary by manufacturer. 6 This display capability limitation could cause confusion, appear as a lack of information, and potentially under- mine confdence in ECS/ECDIS and other bridge electronic navigation systems. This challenge can be reduced through training in AIS use, along with real, synthetic, and virtual AIS ATONs. Navigators must also realize that not all vessels have access to the information available via AIS. This will cer- tainly be a downside, but must be considered in the con- text of watchstanding. The threat of GPS signal disruption, management course, while taught in the later parts of many curriculums, is generally the principal course requiring integration of all the sources of information on the bridge. Bridge Information Management While it is important that mariners-in-training receive instruction on electronic navigational aids, it is also impor- tant that they don't overly rely on these tools. For example, in a National Transportation Safety Board (NTSB) ground- ing report, the probable cause was determined in part to be overreliance on the automated features of the integrated bridge system. On the vessel's trip from Bermuda to Boston, the bridge crew failed to recognize the GPS had reverted to dead-reckoning mode, and had been in this mode for hours. The navigators also failed to identify visual cues, such as shore lights, blue and white water, and ATONs, as the vessel neared land. The vessel ran aground 17 miles off its intended track, a day and a half after departure. 3 However, in the case of a bridge allision, the NTSB found the opposite was true, as the bridge team and contract pilot focused on visual aspects of the span's height and bridge lighting to mark the navigation span, while not referencing the vessel's electronic chart display. 4 Cases such as these emphasize the continuing need to teach integrating the visual lookout with electronic navigation aids. Further complicating bridge information management, information is used differently, based on the user's experi- ence level. 5 Sometimes what is seen out the window isn't interpreted correctly; sometimes what is seen electronically isn't interpreted correctly. Therefore, the emphasis on cross- checking electronic aids must continue to evolve in training programs. This involves teaching several skills. For example, stu- dents must refne the skill of transitioning between manual and electronic navigation. Additionally, mariners must be trained to check the validity, accuracy, and reliability of different forms of navigation and must develop the habit of quickly scanning displays for information while main- taining a visual lookout. This type of training reinforces technology's role, which is to assist in the decision-making process, not to dominate it. AIS ATONs As far as aids to navigation are concerned, adding AIS to ATONs is a logical progression beyond the requirements for AIS Class A units and provides integration opportunities with radar/ARPA and ECS/ECDIS. AIS allows vessel iden- tifcation; and, in some cases provides a greater look-ahead capability, especially in confned waterways. With the evolv- ing role of AIS, educators should pay particular attention to training in its use and interpreting the data it provides. Promoting safe navigation with the electronic chart display and information system includes integrating the visual lookout with radar and ECDIS scanning techniques. Photo courtesy of the author.

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