On arrival on the Bridge, I was welcomed by two guys verbally and gastronomically.
The gastronomic part was demonstrated by the Norwegian coffee and Waffles.
These I consumed whilst chatting, predominantly, with the guy who did the
steering and used the radars. It's my lucky day - the 13th - but yesterday was the
Friday!
I had previously heard from my Dutch lady-friends that there isn't a `big wheel' to
steer with (just a little one!). This, indeed, proved to be the case. There is a `10cm Radar'
continuously surveilling the scene and plotting targets onto a display, normally with a 6-mile
range with OUR position offset to the bottom of the screen. He doesn't usually employ the
`range rings', but when he does they are normally separated with half-mile spacings.
Judging by his answers, there is no MTI (Moving Target Indicator) facility and no PC
(Pulse Compression) either. When attempting to demonstrate possible answers, his `controls'
only changed the `gain control' with the inevitable loss of small targets !! Whichever way the
boat weaved ( and it weaved about a lot!) `straight ahead' was always at the top of the screen.
`Boxes' of data could be created at the side of the main map, - and selected `targets'
would have their data displayed. He also selected `clutter plots' to prove the answers were
reasonable. That is probably the reason why NO `MTI' techniques are used on the Radar -
MTI is essential when most targets on the screen are aircraft. However, the most likely things
to run into one's own boat here are not moving targets, but any one of the estimated 100,000
islands up the coast on route. Clearly, the navigator/pilot has to see all of these on his screen
- well, - the nearest ones anyway!! This is not the `clutter' of the radar screens for controlling
aircraft,- but significant obstacles that one must miss. The rain clutter appeared as `wispier'
smudges on the display.
The boat is under manually-assisted autopilot almost the whole way! It is not
programmed for the whole journey (Heaven forbid!!) but manually SET (not by a big wheel
or keys) by a small knob by twiddling between thumb and fore-finger. Once twiddled, the
boat continues on that heading no matter what the sea is doing. The heading is displayed in
digits alongside the speed digits which the autopilot also controls (normally set to
approximately 15 knots).
To enable the digital heading-setting to have a `meaning', that course is displayed on
the screen - and unerringly is threaded through the myriads of islands. His course-setting
activities (which involved a rapid twiddle to the desired heading) sure explains the high roll-
rates that I'd noticed from the discomfort of my own cabin!!
He only comes off the automatic pilot's pre-settings when` docking' or precise channel-
following (where the submerged channel boundaries are not even visible to the passenger! -
except for peering downwards into the water off the side of the boat when it is light. There
were many such occasions during the long expedition.
I did not witness any noticeable processing of the Sonar system which they
undoubtedly use. The submerged channels have to be navigated very carefully, sometimes by
lights, sometimes by markers - sometimes by sonar !
My query on radio-beacons wasn't understood (he understood light-beacons) and it got
the same response as my question on Satellite Navigation. On the latter, however, he did
show me the GPS (Global Positionning System) equipment and its display. The display had
push-button controls and a sort of `windows technology' assistance in the computer dialogue.
My questions about identifying and distinquishing targets from clutter may not have
been understood. A specific question, such as "How did you identify that target on the screen
as a boat and NOT a small island?", produced an answer (accompanied by a pointing gesture
to his right) of "I could see it over there!"
Following up my questions about recognition in conditions of fog and darkness (i.e.
distinquishing between clutter and targets) I could not acquire any satisfactory answers. I feel
sure that had we both spoken the same language technically, matters might well have been
improved on the assumption that he was a technical man and not just a user (driver) of the
equipment.
Questions about EMC were not really understood either for the same reason. The
severe interference on the 10cm radar display prompted my questions on this.
Altogether, an interesting diversion from previous sightseeing was had - and it gave
me different perspectives on `motoring along the coast' and ship-board radars as opposed to
airborne and ground-borne radars with which I have become more familiar. I was very
indebted to my Norwegian friends for this.