Does any one plot a course on a paper chart?

[jfm]

I look at paper charts but never put pencil on them. Just move the cursor on the plotter, join the dots electronically, and the autopilot drives the boat along the course. If I need to know my position I look at the plotter. I look at a second totally independent GPS to see that it says the same as the first, now and again, to confirm the GPS is working ok.

I cant understnad why you bother working out EPs. Whatever you compute, the GPS is the correct answer. If you dont trust the GPS, an EP wont help you. If a GPS computer goes nuts, it will likely give you a nutty position in Birmaingham and then it's obviously bust so at that point you start EP calcs from your log book. A GPS is unlikely to be just a bit out, like 5 miles. And if it were you would (mistakenly) believe the GPS not your EP. So the solution to worries over GPS set failure is to carry multiple GPS sets.

I agree you need a log on long trip. If all the computers bust you need to work out an EP. I dont like having the electronics store the log, because if they bust you lose the data. I therefore have a paper printer (the Navtex) that prints position, heading, course, speed, time, every 15 mins. If the electronics bust, I have paper record. And it's a much better record because the info is printed characters, same format, precise time intervals, etc. TCM you have this too only your printer is in the cupboard above the downstairs TV and you never remeber it's there and never turn it on.

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[Artie]

I live in Guernsey so whenever I go further than Jersey or Alderney I work out a route on Paper charts and transfer the way points to the GPS. ( I lost all electronics in the middle of a storm this summer half way between Alderney and the Needles) Every 15 mins I have SWMBO or whoever else is with me mark out position on the rhum line on the chart. More importantly I record on my dictophone - Time, Pos, speed course etc which means that if we end up in the drink I am able to say on the hand held where I was last recorded (that is assuming I do not have time to grab the EPERB!.

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[tcm]

Re: ooh

yesh, i know it is there but it has run out of paper. Also forgotten how to turn it back on. Also a bit boring looking at long bogroll. "Where tf are we?" "well, at 10:35 erm french or bst or UT we were at um er somewhere else, exactly, and before that we were at another place else ". Excellent.

Non-tidally, can't beat a stack of gps's. That learner loaned me his and the git has pinched it back so i am down to four again.

Even tidally, you will get there with gps and no tide tables and at 20+ knots it will make sod all difference cos of the whamming time at the throttles will easily overtake Captain 2B Plastic Ruler who will (as proven hereabouts) fail to know how to allow for easterly or westerly variation or deviation "i always remember - Total Westerly Add True Magnetic And Variation East - TWATMAVE" erm..

Note: none of the above should have any bearing on my YM theory test taken recently, results due soon. Q1: plot this fix. Q2: work out an EP. Q3 caluclate a CTS. Q4 calculate the tide in salcombe. Time allowed : 2 HOURS!!

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[jfm]

Entertaining logs

It might be a bit borig looking at bogroll, but ferchrissakes what do you expect? Do you want it to entertain you? Praps link the NMEA feed to internet so it can print a few jokes in between log entry (Eg "This is your navtex printer. The fact you are reading this means all your GPS is down becos Dubya turned it off. Sorry mate I forgot to collect the data so I dont know where t f you are either")

Agree stack of GPS is best. Incl 2x battery powered. Whatever any ragboater says, when GPS is working the easiest and most accurate way to get your position is multiple GPS sets. The log - whether hand written or boring autoprint - has only one useful intrinsic and irreplacable purpose, which is to allow you to calc EP if the entire GPS network shuts down (and you happen to be in the middle of ocean - if anywhere in med you can just head north and you will reach civilisation before you run out of food).

 

[MainlySteam]

As a raggie owner (but of biboatal persuasion), what a refreshing thread, nothing like a bit of speed to make you concentrate on the fundamentals.

I have come to conclusion that raggies have so much time on their hands getting from A to B they have to spend it working out EP's and then spend their time worrying and working out why that does not match the GPS fix. Obviously at sailboat speeds things like current can be very important but it seems many even think you have to work out an EP to get that too (how, I don't know).

Maybe it is a bit like driving a fast car - you tend to place more attention on watching where one is going, rather than looking back analysing why you are not where you thought you were.

John

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[Gtdog]

One of the scary problems with GPS is that when the system wobbles it does so slowly, this leads to a gradual loss of accuracy.
Delivering a boat to Falmouth recently the Gps position was over .5nm off, thankfully the 1/4 hourly plots showed this gradualy occuring, by Plymouth I had transfered to the chart plot done at home.
Chartplotters and GPs systems in general can lead to a very false sense of security, as we become over reliant upon the little screen.


<hr width=100% size=1>Work? You call this Work?

 

[jfm]

GTDog, was this a prob with the global system, or just the GPS receiver that you were using?

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[bob_tyler]

As a raggie I wouldn't care on a trip like that if my EPs were only .5nm out. I'd be happy within a mile or so (except in v poor visibility.

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[Steve_D]

Blimey

I use GPS all the time. on the boat, walking, cycling, nav in the car and I have never had an error more than a few metres. When I'm out it is always swiched on and I check with it continually so that I'm happy that what I am seeing matches the plotter/readings.

Was there any military around I understand they can do local "theater" jamming and introduce an error I believe that other things such as power lines etc can cause problems as well. Other than obstructions I can't think of abything else that would cause such an error.

REgards


Steve D

<hr width=100% size=1>No. I was right the first time....

 

[Steve_D]

Re: Yes!!

I use the GPs backed up by the mark 1 eyeball and on longer trips a "pre-flight" nav plan on paper

I have a colleague that has one but doesn't switch it on cos he don't want to be dependant on it "its just there for emergencies" so there he is, thick fog, not entirely sure where he is cos the fog crept up from behind, Time to break out the GPS mmmm "what does that button do?", "whats the beeping?", "where did I put the manual. no it all right dear everything is under control"

I cant make him understand that he needs to be COMPLETELY happy with its operation an "emergency" is not the time to be learning how it works.

personaly I have two, one fixed but will run off batteries, one handheld but will run off boat power. both GPS' and Handheld VHF will run off the same cells (AA) spares kept sealed in grab bag all waterproof to IP7 and all with integral ariels

<hr width=100% size=1>No. I was right the first time....

 

[MainlySteam]

We have GPS going on the boat at least 30 hours a week. Current one is 7 years old and I have never been able to doubt it, ever.

Due to the dependance of non-military users on GPS (including aircraft in many countries for area navigation and non precision approaches), and the assurances that service will be maintained outside of hostile arenas, I would suspect that any problem seen on ones own vessel is almost certainly to do with the on board equipment and its installation (receiver, antenna, power supply, on board interference).

John

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[DavidJ]

GPS units do go wrong. My Raymarine antenna (only just over a year old ) went into intermittent failure then failed completely. It showed "no signal" rather than a wrong one. Fortunately total failure happened in the harbour but it was sobering that although I have a handheld backup I had not punched or paper recorded any waypoints. I had charts so would not have been completely stuck but in a Med chop is not the time to program the handheld.
Raymarine have a 2 yr guarentee so new replacement made with no fuss.

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