Estimated position

I did say more than 12 hours from land (so let's say 80nm), not just out of sight of it. So anticipating an ocean passage once clear of departure dangers and excluding the approach to land at destination.

As I said I don't know of any good reason why one would want to do so except for the pleasure of it. In fact, many have posted in other threads (maybe this one too, I have not reread it all to check though) that at sea they only plot a position of any kind once a day (and that was certainly very common practice before GPS).

John
 
as one who could also be construed as missing a key enjoyment in boating (from the contribution on this thread) I absolutely agree with Chris E (inc the Mountgay) from the inference available from your early post to the acceptance of your second.

I would add that I go places and routes with my plotters that many with more traditional methods would shun - however rather than simply heading in with a forward looking sonar (pah!) I 'enjoy' working through the tidal height and current implications, factoring in the degree of detail the chart (plotter) is presenting me including rock v sand (the former changes charted depth less often!), waves and even wash............likelwise when snugging up in an anchorage I will enjoy the exercise to calculate the lowest depth I can expect under the skeg for tidal height and swinging whilst sipping my M&C and watching the sun go down.
Finally I am nearly always single handed, have no autopilot and have to actually stop the boat (engine neutral) when leaving the helm................
 
I note my position every few minutes on my chart plotter, well every time I look at it actually. Do you think you turn on the electric gizmos then forget them till you arrive?
Unless you are using the rolling road feature of a chart plotter you have instant position everytime you look at it, not every hour or so or when you remember to plot it on your paper chart.

"Oh look we're here" short period of time"Oh look we're here" short period of time"Oh look we're here" short period of time "Oh look were here"..... Power failure "we were there just a minute ago". " Get the charts out".......
 
I am not anyway gifted at Maths (or arithmetic), but I find I do like making the basic mental calculations of: If I am travelling at xx knots and have yy miles to go then I have another zz hours to go. and also the calculation of distance travelled. Oh, and also the distance to and from a waypoint / bouy / known mark.

It serves three purposes, gives me a sense of progress, a broad idea of where I am and also lets me know when I am getting mentally tired when doing simple sums becomes a problem and that I should be aware of this when making decisions / it's time to have a kip / something to eat!
 
I'm a bit like your colleague, I'd rather sail, but haven't the time (until I retire), as I have no interest in racing, nor day boating. We like to cruise and explore, time is limited, and the mobo facilitates this. We did a 1100m cruise this summer that would have taken three times as long under sail alone. So for now our sailing will be limited to charter, and the mobo for the rest of the year coastal and inland.
 
No no,

You're missing my point.

It makes no difference to me how people choose to navigate, all I'm saying is that it's safer to keep a note of position not reliant on electronics (ie, written down somewhere) so that if there is a power failure, the mast falls down, the gps aerial knocked over etc then an approximate position can easily be worked out.

Isn't it part of good seamanship to be prepared for the unexpected?
 
We were on a maiden voyage with our new boat back from Les Sables D Olonne (France) to Ile d Yeu (approx 30 miles) last year, weather deteriorated a bit and POP. All electronic systems go off! PLOTTER, GPS, LOG & DEPTH, AUTOPILOT. Out comes the H/H GPS and paper charts and on we press - no panic - no sweat.

Turned out to be a popped fuse inside the autopilot which powers all remaining gear.

Fuse failed due to stray strand of wire inside a junction box inside the wheel mounted instrument pod - presumably moved a bit when we dropped off a wave.

Took me all the next day to find the autopilot, fuse and short.

(We always keep a H/H gps and spare H/H radio in a small metal biscuit tin - helps guard against lightning strike blow-up).

Just goes to show - s**t happens and you need a backup plan!
 
Best Estimate of Position

Amusing stuff. Bunch of navi-religious fanatics.....

Does it matter what gear you choose to spend your pennies on and have on board, provided you can use it to gain the 'necessary mental picture of place and hazards' sufficient to keep out of the dwang?

I discovered I still had a Consol chart in the depths of my underbed chart stowage, at home. That brought back lots of memories from my early racing days, pulling good fixes out of the ether when it was blowing a hooly and no-one else on board could hold a protractor on a chart-table. ( Pilots - couldn't count above 'One, two three, a lot...' )

I also remember a friend with the latest, top-of-the-range Raytheon Integrated thingy - which worked fine. He got out of the habit of looking out and running a mental plot, we got into a humungous rainstorm in close waters up around Mull, and his Raytheon thingy promptly ran off the edge of the installed chart cartridge. The whole screen went grey, to match the world outside.... Problem was, he couldn't find the rest of the cartridges, knew he knew not where the h**l we were, and panicked big time!

I was useless, with hysterical giggles....

Navigation is a thinking skill. The decisions are made by exercising the muscle between the ears. No-where else.

The kit - be it ould sextant or head-up integrated tactical holographic display - merely provides info. Sometimes duff info....... Sometimes no info......

Rant over, over.



/forums/images/graemlins/cool.gif
 
OK - Im telling you you are wrong.
If on passage we do it - helps to pass the time.
The rest of the time we just use modern technology

Claymore_July_06_115.jpg
 
Where the instruments are all powered from the autopilot computer then it is good practice to leave that power source intact but ALSO put 12 v (or whatever the appropriate voltage is) on the DC to the instruments outside of the autopilot computer.

So, using the Seatalk bus as an example, one just connects 12 v to the 12 volt line in the Seatalk cable anywhere one wants (as well as the supply to the computer). This means that if the autopilot computer should fail and so not maintian the supply to the instruments (or the fuse in it blows) there is still power to the instruments.

In our own instance, the autopilot computer and linear drive is on one breaker and the parallel power source is on another so a fault on one throwing the breaker will not bring the whole system down. Either or both will drive all the instruments, but only one drives the autopilot computer as well.

John
 
That too is how our instruments are wired, Autopilot + Instruments on one breaker and the GPS/Plotter on another. However we also have a cockpit plotter with integral GPS, not connected to the pilot or instruments and running off a different battery bank entirely.

But then, like Kev said we are also usually monitoring DTW, BTW, SOG and COG because once clear of inshore pilotage the cockpit plotter screen is switched from chart to GPS data information screen. Even my memory allows a pretty good idea of the last BTW/DTW I remember from which to plot a position on a paper chart IF it were ever necessary. Spacial awareness maybe!

I do hope though that when armagedon does come I will remember where the torch, or the backup candles and matches are so I can find the pencils - oh and the pencil sharpener. /forums/images/graemlins/smile.gif
 
In my case it would not have made any difference how it was powered because it failed due to a short circuit between the seatalk 12V+ and ground in a junction box and the log, wind, depth & gps were on this. The fuse going in the autopilot was the safe fail component. Had it been powered any other way then another fuse would have failed (or wire burnt out). Incidentally, the wiring (and short) was factory standard fitment.

My point was that things can and do go wrong and you should always have a back-up plan which we did have. We reverted to a H/H gps and paper charts, we could also have coped with total GPS loss aswell, because we had a log entry about 15mins before black-out and we knew our approximate speed (got to remember we had no speed/dist reading either, which is where the h/h gps came in useful).

Incidentally, later on the trip (about a month later) our VHF failed too, but we had 2 h/h vhfs as backup and connected one of these to our main aerial with an adaptor we had on board. We also had a backup aerial and a fishfinder which served as a backup depth indicator, wired totally separate. We now also have a 2nd GPS (NMEA) from an old plotter which provides position data to our VHF(DSC) which is wired separately to the nav gear.
 
Claymore, that is exactly what Ive been saying. There is no argument, so far as I'm concerned, about how you choose to gather information, it's just whether it is a good idea to make a note of that information elsewhere than on a screen.

And I'm talking about on passage, not on pilotage; on pilotage you can always work out where you are by looking out of the window.

If you are very familiar with the waters and I'm not, your pilotage may be my passage making but that matters not one jot so long as we can both figure out where we are when the lights go out!
 
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