capnsensible
Well-Known Member
The whole point of stop and anchor is that it's easy. Works for me.....
What did PhillM do wrong?
- Thread starter Tomahawk
- Start date
Tomahawk
Well-Known Member
..
Ain't necessarily so..
On the East Coast it is always shallow so your anchor can do something.
On the West Coast of is often very deep or too deep to drop the hook ... then hard and dry in a sharp hurry.
And given that context, I can understand why PhillM wasn't looking at the echo sounder all the time.
Ain't necessarily so..
On the East Coast it is always shallow so your anchor can do something.
On the West Coast of is often very deep or too deep to drop the hook ... then hard and dry in a sharp hurry.
And given that context, I can understand why PhillM wasn't looking at the echo sounder all the time.
Wansworth
Well-Known Member
Was off the Galician coast with no engine ,no wind no e ho sounder in thick fog,so I anchored using all the rope I had attached to the second anchour.........morning and the fog cleared and we where about a mile off the Cies islands,anchoring works!
Tomahawk
Well-Known Member
Fair point..
But consider how long it takes to deploy every rope on the boat? Time and more to go bump whilst sorting them out perchance?
But consider how long it takes to deploy every rope on the boat? Time and more to go bump whilst sorting them out perchance?
Baggywrinkle
Well-Known Member
GPS in car navigation systems don't work like they do on boats. Vehicle GPS improves accuracy by using a map-matching algorithm. As it's a car it assumes you will be on a road, so it starts from a GPS position, collects track information from the vehicle odometry (gyroscopes, wheel speed etc.) to create a track and then goes to the point on the map indicated by the GPS and tries to match the recorded track to a segment of digitised road. This is then weighted to ensure you don't skip backward and forwards from one road to a parallel road but it does still on occasion happen if the fix becomes less accurate. What you will probably find is that the GPS 'track' was out by a few metres but was consistent, but the track from the vehicle odometry matched the parallel road geometry much better so the icon jumped.
Another problem with vehicle GPS compared to boats is reflected signals from buildings which degrades the GPS accuracy in heavily built up areas.
The vehicle odometry and map-matching is the reason why an OEM navigation system will track you accurately in a tunnel whereas a TomTom, Garmin or Bolt-On navi will not be as good.
Wansworth
Well-Known Member
Some where on reels and others hanked,oI kept a tight ship!,
RichardS
N/A
We notice when we're on the Eurotunnel train that sometimes the satnav puts the car icon bang on the railway track shown on the map for 5 or 10 seconds but then it suddenly decides that a car can't run on a railway track so it flips the icon over 100 yards to stick in on the nearest stretch of road. A few seconds later it decides that the road is too far away, so we're back on the railway etc etc.
Richard
PhillM
Well-Known Member
Thanks for the contiunued discussion here. All very useful. A few points:
1) I have NOT been into Plymouth so did not know my way in. Next time I shall wait for daylight before entering a strange port.
2) I had made a paper based pilotage plan. My Plotter was backup (and it failed). Also, by the looks of it did my manual pilotage plan. I have to say that its ages (at last a year) since I went into anywhere I didn't know. Perhaps I've got complacent. Certainly, in the past I would have had a set of waypoints in my handheld GPS as backup to my pen and paper exercise. Not sure why I didn't consider that necessary for this trip. Hmm just thinking about that statement, using the HH with Wpts was before I brought a plotter .... hmm
3) I considered anchoring but, a) I had not prepared where in advance and b) there are a lot of restricted areas inside and outside Plymouth. Lesson learned about preparing an anchorage as a backup.
1) I have NOT been into Plymouth so did not know my way in. Next time I shall wait for daylight before entering a strange port.
2) I had made a paper based pilotage plan. My Plotter was backup (and it failed). Also, by the looks of it did my manual pilotage plan. I have to say that its ages (at last a year) since I went into anywhere I didn't know. Perhaps I've got complacent. Certainly, in the past I would have had a set of waypoints in my handheld GPS as backup to my pen and paper exercise. Not sure why I didn't consider that necessary for this trip. Hmm just thinking about that statement, using the HH with Wpts was before I brought a plotter .... hmm
3) I considered anchoring but, a) I had not prepared where in advance and b) there are a lot of restricted areas inside and outside Plymouth. Lesson learned about preparing an anchorage as a backup.
lw395
Well-Known Member
This was a TomTom, not a fixed system with any odometry.
Yes they use map matching techniques and various rickery like putting you on the correct side of the road according to drive on the left or right countries, but the root of the mater is that the fix was somehow more than 100m adrift, so the wrong road was nearest.
This happens with GPS. When you don't have a particularly good aerial, it happens more.
I have designed products with GPS modules in, if you log their output for long enough you will find spurious results.
FlyingGoose
Well-Known Member
Hindsight is a wonderful thing when we look back , we have all done it and we knew better when looking back , this is how we learn through our faillings , it is always hopeful that those failings are minimal .
You have learned and will do thinks diffrently and by posting you have allowed us to share in your learing and some of us will take heed and adjust our own thinking
So TY for posting it is not easy to come on here and show failings that we have all done but most never want tot own up to :encouragement:
lw395
Well-Known Member
Yes there are a lot of places you would not want to anchor. In fact ISTM that safe and sensible places to anchor a small boat in poor vis and go to sleep in Plymouth Sound would be about 2% of the area. not really something to take pot luck on.
First time I sailed into Plymouth at night it was very disorientating, despite having sailed in and out in daylight, and sailed out once years ago in the dark, and sailed dinghies there some years before.
Portsmouth can trip you too, if you approach from a less familiar direction. I know a good bar story about a well known yotty sailing up to a channel mark and finding the wrong name on it.
john_morris_uk
Well-Known Member
I can believe that from my occasions sailing there...
"Is that seagull walking or swimming?"
"Walking"
"Ready about"
humbug716
Well-Known Member
With regards to anchoring in Plymouth Sound, I boarded a yacht which had anchored in fog for safety reasons north of the breakwater. Even the sound of warships manoeuvring around them later that morning didn't wake them up. They in the middle of the main track north of the breakwater fort.
FairweatherDave
Well-Known Member
Sorry Phil, I'm the guilty party in 1) . I misread ......you wrote have been past Plymouth. I would agree with Plymouth being such a big entrance alternative back ups are less essential. Equally I have been in on the ferry at night and was impressed at what a large complex place it is, day and night.
BTW I wasn't implying you did not have paperbased pilotage plan. I think the point is if you get disorientated I would dive to the plotter/GPS to get back on track, and that is the thing you could not do.
KompetentKrew
Well-Known Member
I think two weeks ago I found a C-Map chart on my B&G Vulcan about 150m out. Wasn't anywhere remote, either - Rotterdam or south coast of UK.
JohnGC
Well-Known Member
In Plymouth;
- You will always find QHM very helpful and always on watch. VHF 14 call-sign "Longroom".
- For anchoring locations the anchoring and mooring guide from the Royal Western Yacht Club is a good resource, worth studying and having to hand. https://rwyc.org/anchorage-guides/
John
- You will always find QHM very helpful and always on watch. VHF 14 call-sign "Longroom".
- For anchoring locations the anchoring and mooring guide from the Royal Western Yacht Club is a good resource, worth studying and having to hand. https://rwyc.org/anchorage-guides/
John
Kukri
Well-Known Member
I have been a true East Coaster. Ten foot bamboo pole marked in feet in the shrouds, bower anchor ready to drop, kedge anchor lashed on the foredeck with its warp stopped down on top of it, dinghy ready to launch, one eye on the echo sounder, lead and line handy...
(But with a deeper draft and deeper waters some of these precautions can be relaxed.)
The other gadget that I had was a slide under the companion hatch with a folded paper chart under a sheet of perspex - this was a gadget invented in the days of Albert Strange and today's version would indeed be the plotter in the cockpit.
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lw395
Well-Known Member
I may be a Luddite.
I still like to have copies of the pilotage info on paper I can use in the cockpit. In the Solent, Check Charts.
Further afield, photocopies of almanac pages in clear plastic sleeves.
The passage plan is a folder/ring binder of such sleeves.
Fr J Hackett
Well-Known Member
I am late into this thread but as I see it the fundamental problem was that at some point you lost track of your position and continued to sail unable to confirm your position. You had indeed negotiated possibly more by luck than judgement the western entrance, you did earlier make the sound decision of not attempting the eastern entrance.
Your reliance on the plotter to confirm your position was your downfall because once it failed and you no longer were aware of your position your only course of action was to drop the hook as soon as you could and call for help, both this options have been discussed.
What can you do to improve matters, get an external GPS arial to feed your plotter, I understand you have a small vessel but there is one piece of kit that would have ensured that you could have identified your position and land, a Radar. It does everything you needed and more from your problems with vessels at Start Point to identifying the entrance and breakwater especially if linked to your plotter with a reliable GPS feed.
Lastly going into Plymouth it would have been wise to have a chart of the entrance and to plot your position on it especially in reduced visibility and at night. I suggest that you get one for Baltimore.
I am not being critical as like virtually everyone here I have made similar mistakes during the learning process and been lucky enough to survive them unscathed, I also know Plymouth very well.
Best of luck for the future and the Jester challenge. See if you can fit that external GPS aerial
Your reliance on the plotter to confirm your position was your downfall because once it failed and you no longer were aware of your position your only course of action was to drop the hook as soon as you could and call for help, both this options have been discussed.
What can you do to improve matters, get an external GPS arial to feed your plotter, I understand you have a small vessel but there is one piece of kit that would have ensured that you could have identified your position and land, a Radar. It does everything you needed and more from your problems with vessels at Start Point to identifying the entrance and breakwater especially if linked to your plotter with a reliable GPS feed.
Lastly going into Plymouth it would have been wise to have a chart of the entrance and to plot your position on it especially in reduced visibility and at night. I suggest that you get one for Baltimore.
I am not being critical as like virtually everyone here I have made similar mistakes during the learning process and been lucky enough to survive them unscathed, I also know Plymouth very well.
Best of luck for the future and the Jester challenge. See if you can fit that external GPS aerial
Kukri
Well-Known Member
I spotted Force 4 in Lymington selling off chinagraph pencils... needless to say I bought a fistful.
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