john_morris_uk
Well-Known Member
You’re making assumptions about the accuracy of the charting that is sometimes unwarranted in waters outside Europe.
Radar used or not?
- Thread starter Cheeky Girl
- Start date
tty
Member
When I'm single handing having the option of setting a 3 to 5 mile guard alarm gives added security when sleeping, making dinner, or anything else that takes me from watch. Night passage becomes a lot less dangerous and I can get underway in early morning fog. It's also nice to be able to tap a target on my plotter and see its course, speed and intercept.
lustyd
Well-Known Member
Not really, a chart plotter tells you what should be there, not what is there and that’s assuming everything is up to date and set up correctly. The rocks don’t move...unless you set the geode wrong. If it’s truly dark (and the lochs can be very dark indeed) then useful to have something showing what is there rather than what should be there in theory. More so given that the canyon like nature of a steep sided loch reduces gps accuracy. It’s the difference between proceeding with extreme caution and proceeding with confidence. Obviously you’d use the two together for the reason of underwater rocks mentioned above.
RichardS
N/A
Graham376
Well-Known Member
I have never understood why so many people have radar or plotter down below where they can't be seen from the helm. Everything we need to see is under the sprayhood.
LadyInBed
Well-Known Member
It strikes me that people choose to praise or lambast navigational aids just to re-enforce their argument of the day!
When I suggest that a CP gives a better representation of what is around you than just using GPS (and presumably a chart) I am told in effect that the drawings on a CP and chart are almost a figment of some cartographers imagination, and that the GPS signal from the Sats are so badly degraded that they can't be trusted. How wide are these Lochs and how tall are the banks that would cause this to be a problem?
I agree that the display on RADAR of the sides of a Loch are impressive, but when the Loch gets so narrow that the other aids output are suspect then I could equally use a torch to see the sides [tongue in cheek].
When I suggest that a CP gives a better representation of what is around you than just using GPS (and presumably a chart) I am told in effect that the drawings on a CP and chart are almost a figment of some cartographers imagination, and that the GPS signal from the Sats are so badly degraded that they can't be trusted. How wide are these Lochs and how tall are the banks that would cause this to be a problem?
I agree that the display on RADAR of the sides of a Loch are impressive, but when the Loch gets so narrow that the other aids output are suspect then I could equally use a torch to see the sides [tongue in cheek].
Graham376
Well-Known Member
We've had chart inaccuracies but in nearly all cases it been with shifting banks which radar obviously doesn't show but, it will show channel buoys which have been moved since chart updated.
Never Grumble
Well-Known Member
How did they not know? Wasn't it obvious?
lustyd
Well-Known Member
My point was that charts show what should be there while radar is real time showing what's definitely there. I only realised that distinction after my own "should I bin the radar" thread. I certainly do trust a well configured and up to date plotter, but I trust it more with a real time overlay of what's out there!
john_morris_uk
Well-Known Member
Each to their own. I enjoy sailing the boat but I rarely steer by hand. Having the plotter and radar below is no hardship and we usually keep a plot of some sort going on a paper chart. I’ve seen people so glued to the plotter visible at the helm that they forget to look up. I’m sure you don’t fall into this trap but for when we want pilotage info instantly I use Navionics on my phone or we have the facility to use an iPad as a repeater of the main Raymarine display below.
john_morris_uk
Well-Known Member
You’re probably right. But a good navigator uses and cross checks all available information. We entered New Grimsby Harbour (Scilly Isles) a few years ago in the pitch black. It’s completely unlit and I was using plotter, echo sounder, Navionics and Radar to cross check that we were ok and safe. It’s very eery closing a rocky coast hearing breakers all around and entering a narrowish inlet with cliffs/hills either side in the blackness. Radar and GPS and sounder all agreed with the charting so we were safe.
Graham376
Well-Known Member
Not surprised, some people are clueless. On another forum, a guy was asking where his holding tank was likely to be and where the galley seacock was located. He'd only had the boat for seven years!
AntarcticPilot
Well-Known Member
Or even within Europe in regions where the sea-bed is mobile, such as the bars of rivers like the Deben and Ore, or estuaries such as the Humber.
johnalison
Well-Known Member
My radar works well but struggles to see the sea bed.
Never Grumble
Well-Known Member
It must have been my naval training that meant in the first two weeks of ownership I crawled round on my hands and knees establishing what everything was!
john_morris_uk
Well-Known Member
I agree. But the absolute confidence that some people seem to have in their plotters and it’s electronic charting is still worrying. I suggest that everyone who goes aground in a catastrophic unintended way thought they ‘knew’ where they were. Quite often by believing what the plotter says without either looking up or looking at all the other data (like the echo sounder) that’s in front of them. But I am drifting the thread.My radar works well but struggles to see the sea bed.
AntarcticPilot
Well-Known Member
But in the areas I mentioned, the banks are uncovered at half-tide, and also show distinct scattering patterns even when covered. I've had the opportunity of seeing the latter effect in the Humber from the bridge of a research vessel moored in Hull docks - the pattern of the shoals was more evident than the return from a coaster in the river!My radar works well but struggles to see the sea bed.
Daverw
Well-Known Member
We are on the Humber and agree that the mud banks just under show up as surface patten quite often
johnalison
Well-Known Member
So you reckon that you can detect a shoal on radar from the change in wave pattern or lack of? I can't say that I have ever tried but it sounds like an interesting exercise next time I get a chance. I can think of some of the Belgian banks that would give a good return but our local ones are more like ripples.
TernVI
Well-Known Member
I recall reading that the majority of yachts which have actually managed to collide with ships in UK waters had radar.
I suspect that excludes the cases where the yacht is moored and gets hit by things like IOW ferries...
I think it's quite hard to safely operate in a multi-vessel colregs situation by radar alone if you are not very practiced.
Most people seem prone to telling themselves the radar image is consistent with what the chartplotter says.
I suspect that excludes the cases where the yacht is moored and gets hit by things like IOW ferries...
I think it's quite hard to safely operate in a multi-vessel colregs situation by radar alone if you are not very practiced.
Most people seem prone to telling themselves the radar image is consistent with what the chartplotter says.
