This conversation has been immensely educational for me and I’d like to say again how grateful I am to you guys for helping to enlighten me. I will pass on my knowledge and maybe this knowledge will help make things a little safer and more convenient out there.
One thing I never realized before this conversation, and which I’m trying to get my head around, is the fact that you guys think in much longer distances and much bigger time horizons than we do.
I’ve gotten some conflicting advice (which is only natural) – a lot of people have said “know the Colregs by heart and live by them, learn to use your bloody navigational gear, and there won’t be any problem”. Others have said something like “don’t make a grandmaster chess game out of it – in open water, stay out of the way as much as you can, use common sense, be as visible as possible, use your VHF, buy a transmitting AIS, and we’ll mostly avoid you if you were too stupid or unaware to keep clear in the first place.”
I do know the Colregs by heart and do know how to use my nav equipment, and [I]thought [/I]that following the rules (especially the rule that if the give-way vessel doesn’t give way in plenty of time, the stand-on vessel must maneuver) was the right way to behave at sea. But I now start to think that some of my assumptions were wrong. In open water, I now understand that you have probably worked out the whole encounter long before I even know you’re out there. It makes me wonder whether it makes sense to wait for 2 miles to maneuver. If at 5 miles off, maybe even 10 miles off, we are on 0 CPA courses, then probably you’re not ever going to manuever, is that right? I am guessing that at 5 miles away, you were long, long ago fully committed to whatever maneuver you made or didn’t make, something hard for us to understand – even one mile away [I]seems [/I]like a long ways to us.
Looking back on my real experience in the English Channel (so probably hundreds of encounters with ships) there were probably hundreds of other encounters which I was simply never aware of – you saw me from over the horizon, made a small alteration of course, and we never came near to each other. My radar will not detect you from more than 12 miles off or so, and I don’t think I can see you from much more than that, either, from my deck which is only 1.5 meters above the water. But I have a large radar reflector which is near the top of my 75 foot mast, so with your powerful radars I bet you can see me for and hour or more before I ever know you’re there.
I always thought that it would be wrong for me to maneuver spontaneously if I am the stand-on vessel – I am obligated to hold course and speed, at least for a while, under the Colregs. I always thought that the purpose of that was to allow the give-way vessel the first chance to work out the crossing. Now I start to think that these thoughts are occurring too late to be of any value – if it’s still a 0 CPA situation five miles out it’s already too late to “give you a chance” to work out the crossing. Maybe at 5 miles off I should just heave-to until there is no potential issue and not overthink it. But this is not what the Colregs say I should be doing.
What I have always taught young sailors is that being a stand-on vessel is not anything like having the “right of way”. There is no such thing as “right of way” at sea. Standing on is not a right, but an [I]obligation [/I]for one vessel to hold still so that the other vessel can work out the proper manuever to resolve the situation – if both vessels maneuver at the same time, no one can work it out, and they may simply maneuver into each other. Now I start to think that this may be to some extent empty theory with limited application to encounters between yachts and commercial shipping – simply because of your longer time and distance horizons, and because of the great difference in speed between us.
Another thing I have learned is that it is absolutely paramount for us to be capable of determining whether or not a 0 CPA situation exists. I imagine a horror scenario is if a yacht doesn’t realize and can’t calculate that you have long since set a course which has you crossing a mile or two ahead of him, and makes a sudden manuever a mile or two off which screws up the crossing, in the mistaken belief that he is avoiding a potential collision which doesn’t exist. I guess a lot of recreational sailors don’t really know how to use their HBCs and don’t really know much more than “oh there’s a big ship over there; quick let’s get out of the way” – and this thought is occurring to them far too late for any really safe manuever. We try to pound it into their heads that they must know the Colregs and must use their HBC’s, but it doesn’t always stick there.
Hmmmm.
We have a crappy version of ARPA called MARPA, which, however, does not actually work. It does not work because it needs precise heading data, and most of us have crappy fluxgate compasses which do not give data sufficient to get usable information out of MARPA. Gyro stabilized electronic compasses and GPS compasses are very expensive and few of us have them. For the same reason, our radars do not give us reliable bearing to target data unless you average a series of logged bearings – very tedious. Our radars are really only good for two things – detection of targets we can’t see, and precise range measurements (which of course is extremely useful).