DST - Decision Support Tool



COLREGS compatible Decision Support Tool - marine revolutionary Collision Avoidance system




System Features

    The risk reduction of groundings by ECDIS systems is already well established, as was shown by the 2007 DNV technical report. Further developments of Track Control systems and GAS (groundlingavoidance systems) are already available as mature products. In that respect, a well equipped modern ship can automatically navigate the globe with little margin for human error.

    Tools for Collision avoidance, on the other hand, are still lacking, and there is a large margin for human error in adhering and interpreting the COLREGS (International Regulations for Preventing Collisions at Sea). The situation becomes even more complicated nowadays due to the increasing traffic on the open seas and along the shipping routes. The introduction of very important tools such as ARPA and AIS, and the presentation of target related information on ECDIS and radar monitors, certainly help but are not enough. The OOW (Officer of the watch) still uses his instincts and react to changing situations in short notice. As a result, the consequences of possible human error can be catastrophic. To minimize such errors, a revolutionary system was developed by Totem Plus: the TOTEM DECISION SUPPORT TOOL.

    The TOTEM DECISION SUPPORT TOOL automatically analyzes the data of all targets and advises the OOW on the required action. The CPA (Closest Point of Approach) of all vessels is taken into account together with the stipulations of the COLREGS. If required, a “Course To Steer” advice will be given to the OOW automatically (see figure 1).

    The Course To Steer advice is based on analysis of data from all the ships in the vicinity, their CPA and TCPA (time to Closest Point of Approach), and their status according to the COLREGS. On the “Navigable Circle” the OOW can see clearly the dangerous sectors (in red), the change of course required (24 STBD !), the new COG (course Over Ground) and the new Course to Steer. All the information is calculated automatically and is continuously refreshed.

    COLREGS compatible Collision Avoidance Software: TOTEM DECISION SUPPORT TOOL, a New tool from Totem Plus. To offer the correct Advice, all AIS and ARPA targets within the required “Alert Radius” are constantly processed and analyzed for close proximity. The Alert Radius is set by default to 12 miles (open sea) but can be changed by the operator to other values (see figure). Same principle applies to the CPA (Closest Point of Approach), which is set by default to 0.4 miles but can also be set by the operator according to the prevailing circumstances. Other relevant values, e.g. Minimal Distance to act on Port Crossing, have default values that can be changed only by the Master. Minimal values that can be selected (e.g. minimal CPA allowed) are limited by specific vessel parameters such as ship’s length and turning radius. An example of a specific ship configuration can be seen in Table 1 (see table at the right side).

    In addition to the “Course to Steer” information, the system gives an alert on “Approaching from Port” situations or “Overtaken” situations. In such situations no “Course to Steer” advice is given as the ship is required by the COLREGS to maintain her course and speed as a “Stand On” vessel, and the approaching vessel should take action to give way. However, once the approaching ship is below the set distance the system advises the OOW on the necessity to give such ships a warning signal (see fig, 2). If the “Give Way” ship is below the threshold set for action - Action Distance - an advice on a new Course to Steer will be given in accordance with the COLREGS stipulations.

    There are several benefits to the TOTEM DECISION SUPPORT TOOL. First and foremost is safety. It provides an excellent tool to help and/ or reinforce decisions related to collision avoidance. In addition, it aids in taking proper action in due time and thus eliminates excessive helm and course alterations. Safe and efficient ship handling will result in fuel saving and schedule keeping.


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