Rob Posted March 28, 2011 Report Posted March 28, 2011 http://www.bbc.co.uk/news/world-europe-jersey-12867753 Quote
Mike Fox Posted March 28, 2011 Report Posted March 28, 2011 Just read this and had a few initial thoughts: - So what speed does the sea-cat travel in fog? - Was the French fishing vessel moving or anchored when hit? - Did the French fishing vessel have a radar reflector (almost certainly yes)? - What chance do we have in fog if the sea-cat can hit something that size? Mike Quote
ChrisE Posted March 28, 2011 Report Posted March 28, 2011 Just read this and had a few initial thoughts: - So what speed does the sea-cat travel in fog? - Was the French fishing vessel moving or anchored when hit? - Did the French fishing vessel have a radar reflector (almost certainly yes)? - What chance do we have in fog if the sea-cat can hit something that size? Mike I read the report and was surprised that the cat had hit anything. Pre 9/11 I was allowed up on the bridge of the ferries and was impressed just how much their radar could see even in the thickest of fogs. Still, I suppose there's always human error.... I'm gald that no one was hurt. Quote
duncan Posted March 28, 2011 Report Posted March 28, 2011 Just read this and had a few initial thoughts: - So what speed does the sea-cat travel in fog? - Was the French fishing vessel moving or anchored when hit? - Did the French fishing vessel have a radar reflector (almost certainly yes)? - What chance do we have in fog if the sea-cat can hit something that size? Mike I read the report and was surprised that the cat had hit anything. Pre 9/11 I was allowed up on the bridge of the ferries and was impressed just how much their radar could see even in the thickest of fogs. Still, I suppose there's always human error.... I'm gald that no one was hurt. I think you will find that one of those on the fishing vessel died. Fog and large waves, such that the radar echo gets confused, are a rare occurrence in most waters but around the CIs you get a lot of standing waves in otherwise benign conditions. Whether this was a factor or not isn't clear. Equally it's easy to assume that the boat was a small craft, such as many of ours or even smaller - again unclear at the moment. If it was a small open boat it may well not have had a radar reflector in an elevated position - but then again I can normally pick up a pot buoy in calm conditions, let alone a boat of any description, but heavy rain or a swell/waves and things simply disappear... A difficult time for all involved. Quote
TomBettle Posted March 28, 2011 Report Posted March 28, 2011 I'm gald that no one was hurt. Sadly they were. One of the French fishermen has been killed. On a selfish note, I hope that the ferry is still running as I am due back from Jersey on her on the 19:30 sailing next Saturday! Quote
Rob Posted March 29, 2011 Author Report Posted March 29, 2011 Seems that it was a 30ft Whelk Fishing Boat - so not small! Question: Does Radar on a high bridge pick up close objects or does it pass over the top? i.e. what is the vertical beam spread like? No doubt there are 100 variations! Rob Quote
duncan Posted March 29, 2011 Report Posted March 29, 2011 Seems that it was a 30ft Whelk Fishing Boat - so not small! Question: Does Radar on a high bridge pick up close objects or does it pass over the top? i.e. what is the vertical beam spread like? No doubt there are 100 variations! Rob the simple answer will be that it depends......... generally the higher the radar the more distance it can see, and the better it sees at distance. lower radar is much better at short distance the tighter the beam width in both vertical and horizontal the better the definition, but obviously for vertical, the more important that the angles all work. this is one of the reasons that yachts need to make the right compromise between height and unit power; they also have huge problems in any sort of 'sloppy' conditions. given the French involvement we will see a very detailed and blunt analysis of cause. It is however confusing for a number of reasons - 1. the boat that was hit is both a reasonably large radar target (and generally a good one too) and unlikely to have had the speed to significantly contribute to the collision. 2. Condor creates a significant wake at speed and aims to give a significantly larger clearing distance than most vessels would 'bother' to do. 3. The fuel costs to Condor associated with slowing down to go nearer, rather than go wider, doesn't make financial sense 4. Condor is a very stable radar platform, equipped with excellent technical equipment and, most importantly, runs at such speeds that it uses radar clearance all the time ie it's not an occasional user! All of the above suggests that this particular combination is the most unlikely poor visibility collision you could envisage....so what the hell happened??? Quote
ChrisE Posted March 29, 2011 Report Posted March 29, 2011 Whilst it is true that the higher the radome the greater the range, you'll will lose targets once close to them if using conventional radar which has a dead zone close to the ship. As I said earlier, the Condor has very sensitive radar so how they missed a 30' ship I don't understand. I'm sure the inquiry will find he answers. Quote
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