One of the interesting things that this article draws out, is how difficult it is to steer a decent (straight) course in fog. I have found that except when racing, it is much better to use the autopilot. As there is (except in very unusual circumstances)virtually no wind in fog, so one is likely to be motoring. Helming when motoring is a real bore, so the autopilot makes sense, it also means that chartplotters, radar screen, radar bearings etc do present a confused picture. The added advantage is that one presents an unambiguous course and speed to others watching you on their radar! On a ships bridge in fog, targets that wobble about all over the place are difficult to plot. Mind you 20 Kts in thick fog is criminal behaviour, whatever the MAIB may have said in this case!
I cant think why the yacht did not attempt radio comms as soon as he saw him ahead on the radar.
Just a thought, especially for yachts without radar, (me) and mixing it with shipping, and then poor viz, I wonder if CG wouldn't mind knowing my position, course and speed which I could update every 20mins. My position could then be plotted and shipping in the vicinity could be warned.
Yup & in fact if you put out a Securite Transmission yourself giving your position course speed when crossing a shipping lane you'll do everyone (including your life insurance co) a big favour.
I've done it in the past and the CG have picked up on it a given a general broadcast with my details.
A couple of years ago I heard (whilst sitting on a mooring in the Alde) a yacht put out a similar call. half an hour later, a US Warship that was clearly near the area, ordered a cargo ship to stop and allow the yacht to clear the separation zone before continuing on its route.
BTW if you ever have the pleasure of listening to the US Navy (and incidentally Lykes Lines - whose officers are US Navy Reserve & Annapolis trained) communicate on VHF, they are quite wonderful, precise, polite, quick and very very firm about what they expect to happen, I hope grey funnel line are as good but I doubt it.
When going to the Netherlands avoid at all costs the "Roundabout" separation zone off Rotterdam, its a real nightmare with ships all going here there and everywhere! Its clearly marked on the charts.
If its your first visit to the Netherlands, you will find it is absolutely wonderful!
One great trip is the MAST OOP (up) route from say Veere up to Amsterdam, takes a day or so and is a great way to see the Holland area and all its small towns!
Can't agree more with David about the delights of cruising in Holland, and especially the "Standmast" route between the Delta and Amsterdam. It gives you a great feeling of power when they lift the motorway bridge at Schipol for you - and even more when they lift the railway bridge at the Central Station in Amsterdam! (Both only happen once a day, in the early hours of the morning.)
Crossing the North Sea is usually much less frought than crossing the Channel, although it is a lot further. You hardly see any ship traffic except in the designated lanes, but again I agree with David: avoid the roundabout!
Once we did a long offshore race which used one of the buoys at the edge of the roundabout as a turning mark, and as we crossed the "deserted quarter" of the North Sea, the sky lit up with red tracer fire. There was a warship doing a live firing exercise. We called the Coastguard, and they stopped it pretty quickly. So yes, it pays to talk to the Coastguard and let them know where you are!
It sounds to me that this Raymarine course was a great del more useful than the one day RYA radar course. I did this recently and was extemely disappointed. On the one hand the presentation by the tutor was poor, and he was not very familiar with the Lightmaster simulation software we were all using, but more importantly the syllabus as set by the RYA seems to be very out of balance. Far too much time was wasted in irrelevant details like transmission frequencies and the fact that metal boats give better echoes than wooden ones. What a surprise! Surely this kind of thing could be left to the student to read up. The real meat of it, especially as I would have thought that most people with radar would also have a plotter so do not primarily use their radar for navigation, is how to interpret the radar screen for the purposes of collison avoidance in poor visibility. Yes, this was dealt with, but it only formed (a relatively small) part of the day. Surely this is where the emphasis should be on the RYA course and the kind of "what if" simulations that Cathy describes would be invaluable. Come on RYA, get your act together and review the radar course!
There is another incident of East Coast near Lowestoft - where a yacht altered course INTO collision - basically no plot or real understanding of Radar.
Both Vessel and Yacht were joint to blame in the report - vessel made small alteration to clear, was still at sea speed, yacht didn't plot or interpret radar correctly and altered into collision course.
These incidents all to well illustrate what was termed RAC in the Merch. years ago - Radar Assisted Collision. In early days of radar fitted to ships - training was very poor, many in fact receiving no instruction on use.
Modern radars even yachts have good means to plot, BUT those who say "put EBL on target" forget a fundamental item - ONLY if compass stabilised display will you get good idea of CPA. Yes if the target tracks along the EBL - then of course it will cross your centre spot - BANG.
Radar is becoming a common item on many yachts now and I hope that people take time to learn how to use it even if only basic.
How many here can take info of a radar and actually run a paper plot, calculate time to CPA, and distance CPA .... calculate effect of proposed alteration ? Etc.
Me with a serious struggle!!! Add another target or 2 then I d be stuffed.
Be lost without ARPA doing the work for me, especially in a busy traffic area. Indeed probably go as far as to say impossible unless you have a bridge type setup with plenty of space and at least one other person to continue lookout/helm/radio watch/navigation.
If anyone is interested in an old publication, I don't think Joe Shell will mind people having a copy from me if it saves lives .... it's the Cadets Plotting Manual from the 70's when I was trained. Then contact me via : nluther"at"solent-life.co.uk replace "at" with @.
It is based on a PPI type radar that we used chinagraph pencil on - but the rules and method still stands. The exercises in it are intended that you use a radar plot sheet. It's good background knowledge to the art of Radar use.
For those interested - you can buy Radar Plot Sheets in a folder but they tend to be designed for a resonable size plot table as on a ship. So you can substitute an A4 raph paper booklet. Using drawing compasses you can draw in your own circles based on the graph paper scale. Using graph paper makes the job actually easier once you get the hang of it, in fact near enough free-hand plot if you also draw on compass rose radials. With practice you could plot in quick time on your knee in cockpit if your radar does not have autoplot ... verify if it does !!!
Hi Nigel. I'm all for doing things properly, and have certinly read the instructions on doing paper plots, but I endorse Wolfie's comments. When sailing two up on a yacht, caught out in fog, in practice we rely on MARPA and are too busy keeping on old fashioned lookout to do paper plots. Fully accept that MARPA isn't foolproof - though so long as the boat is on autopilot it works extremely well!
Also don't hesitate to tell the Coastguard your position. We were once caught out by fog right in the middle of the Dover Strait TSS, in the days before we had radar. Dover CG appealed for visibility reports, and I was right in there, seeing it as a way of broadcasting our position to other shipping. They then, as David said, gave a general broadcast with our details.
Don't misunderstand me ... I know full well that often hands are too full to do paper plots etc.
My point is that Radar is sold across counter and often ftted with no real idea of how to use it - or limited knowledge that can actually be dangerous.
Spot on Nigel, this is precisely why it makes sense to steer by autopilot in poor vis, then the true bearing of the target is easily monitored.
And I still use a china-graph pencil on my display, it works just as well on an LCD screen as it did on a CRT display!
Another tip is to take the bearing and distance of the target and plot it as a waypoint on your chart plotter. If you do this every five minutes or so you will see exactly what the real (True motion) vector of the target is! This coupled with ones own course and speed (Track as they insist on calling it in the plotter manuals) enables an absolutely precise plot to be maintained, and it requires no paper (plus of course it keeps a permenant copy which could possibly be useful as evidence at a later date.)
I really do agree about the lack of user knowledge and experience that most yachtsmen have with both Radars and Plotters.
Periodicly I make myself do what I had to do when I took my Radar Ticket in the mid '60s, con the boat blind - I have a remote control autoplot (brilliant by the way! Esp when raining!) - so I can manouvre the boat relying totally on electronic means.
A few weekends ago, when we had bad fog and almost zero visibilty, I sailed from Walton Backwaters to Ramsholt on the River Deben The first thing I saw after leaving Pye -End buoy was the Horse buoy inside the Deben. (And yes I did call Harwich VTS on the VHF just to double confirm it was clear when I crossed the shipping lane.)
You should all have a go, it doesn't need top be foggy and you leave a crew on deck in case you are concerned you'll get it wrong. Its only by practising that it will become second nature and easy to do when it really matters!
David .... you will know as I - that effective Collision avoidance is easiest made with Relative Motion plot ... not true motion. This is where many even professionals fell foul of plotting when models as Situation Display Radars appeared ... also why many older masters required youngsters to take compass bearings of other vessels to make sure they didn't fall foul !!
The truest reference to determine collision potential is compass bearing - but that is not possible in reduced viz.
I've been following this thread with some interest. To be honest, however, I'm getting confused by some of the comments made. I have only had radar on my boat for a short while and have not yet had cause to use it in earnest in conditions of limited visibility. It's also an older set and I don't have Marpa.
As I explained in an earlier post I attended an RYA radar course and was greatly disappointed. It didn't focus on just the issues that this thread has been developing. I have been reading up on the subject, not easy in itself as there don't seem to be any really detailed books out there, but remain a little confused at points.
Cathy, would it be possible to commission another article on this topic which spells out how to do it in A-B-C terms and also lists the potential errors that can be made? For example I thought that, sailing shorthanded, with radar set to Head-up, I could put an EBL on a target and if it moved off that then I was OK, but I think it has been suggested that this is not sufficient.
It's all very well for "old salts" to lament the lack of experience/understanding of others with regard to radar, its uses and limitations, but how are we to change that situation when the RYA radar course is next to useless, its booklet worse than useless, and the only book I can find (Tim Bartlett's) is good but perhaps too basic on colision avoidance? I'm very willing to learn but how do I do it?
(a) almost every radar nowadays offers stabilised displays (north up or course up) if the owner has the wit or the wallet to connect his radar to a compass.
(b) with a stabilsed display even the simplest EBL test will quickly tell you whether there is a risk of collision, or whether the approaching ship will pass ahead or astern
(c) A4 plotting sheets are readily available, published by Amberley Marine (try www.bookharbour.com, amongst others)
(d) a dry-wipe marker works better than a chinagraph, and is easier to obtain.
(e) It is hard to think of anything much less relevant to collision avoidance than True Motion. You want to know whether the approaching vessel is likely to hit you -- not which bit of seabed he is going to pass over on the way!
(f) The RYA radar course syllabus includes nothing at all about frequency, but aims to achieve a good working knowledge of collision avoidance plots. (Graham, if you would please respond to my earlier attempts to contact you, I might be able to do something about the problem you experienced. But if you just want to slag off the RYA, I can't)
(g) I guess Graham is referring to my old Fernhurst book. But there are several alternatives, some older, some newer, some more superficial and some more detailed. The Fernhurst book is (deliberately) at the more user-friendly end of the range. You wouldn't expect me to plug a commercial competitor (would you?) but if you want a little more detail, try the Adlard Coles book of Electronic Navigation. If you want a lot more, try The Radar and Arpa Manual by Bole and Dinely or the Radar Handbook by Skolnik.
I'm sorry, I wasn't aware that you had attempted to contact me earlier. My email is graham@loveland.org.uk
As to the "frequency" issue page 4 of the RYA's "An Introduction to Radar" does have a section on frequency, albeit small. My concern is not in any way to slag off the RYA (I also recently attended the one day radio course to update my old VHF certificate to DSC and felt that that was a very good course), but to make the point that in my opinion there is an imbalance in the course syllabus. My point was that although collision avoidance is covered, it does not occupy anything like as large a place in the syllabus as it deserves, given that colliison avoidance is surely the main use most of us make of radar these days. In addition I was making the point that the kind of "what if" simulations that Cathy was describing on the Raymarine course sounded much more useful than what we did on the course.
Thanks for the other book recommendations. I have looked in the books sections of several chandlers and found nothing much at all on radar. Perhaps I should have tried searching on "Radar" on Amazon, but would not have known what to expect from any given volume.
Whilst I agree in principle about the use of relative bearings as opposed to True Motion for collision avoidance, that is only a small part of the probem.
What I like to understand is exactly what the target is doing, what speed, what course and where it is in relation to for example shipping lanes, buoys channels, pilot stations etc etc, then one can often predict what its likely movements are. It is also important to establish whether its speed and course are constant, using a cheap yacht radar and inprecise course sterring it is almost impossible to guage real relative motion.
Armed with both the relative and true motion information it is possible to reach a properly informed decision.
David - I don't disagree with what you want from it ... but I think given average Yacht radar - the list of data you want is probably pushing many limits (operators I'm talking about).
Relative data referenced to your known position in relation to specific geographic / marine mark is sufficient data to make a VHF call and ID the vessel or to CG. Predicting a vessels movements is not on my list !! having been a yachty since a young child and also 17 yrs as Merchant Navy Officer standing bridge watches ... latter being the guy who left Standing orders !! Don't misunderstand me - I know there are many others with far more experience / knowledge than I and I know that I make errors, don't know all - still learning.
I just feel that particularly via this thread that simple is better !
I wonder if there is a conflict in terminology here, because if your equipment can't show relative motion reasonably accurately, it certainly won't be able to produce anything remotely resembling an accurate true motion display -- even if there were any practical purpose to be gained by doing so.
And surely it is significant that the MAIB report into the Wahkuna/Nedloyd Vespucci collision criticised the container ship for using a ground-stabilised display rather than sea-stabilised. If highly trained professionals make such a fundamental mistake, what are the chances of a part-timer or amateur doing so?
For most yachtsmen, without the resources of a trained bridge team, with a small scanner and small display, and oftetn with little or no dedicated radar training, I think there's a lot to be said for keeping the procedures as simple and reliable as possible.
Incidentally, all RYA radar instructor courses since the Wahkuna incident have made the point that assessing the CPA is not enough -- in a near miss situation, it is essential to be able to assess whether the approaching vessel is likely to pass ahead or astern
