The ‘Ship's Wheelhouse of the Nineties’

Abstract

In this Journal (vol. 42, p. 60). Schuffel, Boer and van Breda present a very comprehensive scientific investigation into bridge design and manning. The cross-track error during transit is selected as a criterion for overall safety. However, there are some questions left unanswered, and the article appears to address only part of the problem. Without doubt, the bridge design and location of the equipment are of the utmost importance, but the wheelhouse layout cannot be treated separately from instrument performance, nautical procedures and crew competence.The simulator experiment deals only with open-water conditions in an area with good Decca coverage; no reference is made to open ocean or to restricted waters. The automatic positioning proposed by the authors will need at least GPS to be available on a worldwide basis and can even then not be used in restricted channels until a worldwide coverage of differential GPS is available. 1On p. 62 it is, possibly by accident, stated that ARPA and radar are superior to the human eye for detection. Operational experience has shown that radar is vastly superior to the eye for navigation, range and bearing measurement, instrument error monitoring, etc. but has very poor performance for the detection of small targets in clutter conditions. The integration of all the conventional ship's instruments (p. 63) into the same display as ARPA and radar appears to invite confusion and will also be vulnerable in case of a display breakdown. Common practice in existing high-tech bridges is to locate these displays in an overhead console over the front windows of the wheelhouse, where they are clearly visible from the two conning positions. Figure 2 shows a picture of a conning console with a large chart table with an optical plotting device. Is it the authors' intention that actual chart work should be performed at the conning position, or should the passage plan be detailed enough to provide sufficient data for cross-track monitoring ? Has it been considered whether the large table in the front console could be replaced by a small size paper chart or an electronic plotter, to present the passage plan data in the form of, for example, turn radii, parallel indexing data or nav lines on the radar or ARPA display? In future, the ECDIS will probably prove to be very useful for the purpose.The remaining cross-track errors from the experiments seem to be rather large under the circumstances. Could part of these errors be caused by less than optimal turn planning and control? There is no reference in the article on this subject.There is now substantial operational experience available from ships with highly automated cockpit bridge layouts. Since 1974, the Silja Line has operated large highspeed ferries on a year-round basis between Finland and Sweden.2 Ten of the 11 hours transit are spent in the very narrow Aland archipelago. At present, the third-generation ships (36000 g.r.t., 22 knots service speed) are in operation, and the fourth-generation ships are under construction. Their record ...