Can you navigate without using GNSS?

zoidberg

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'A long time ago on a passage far, far away'.....

.....I was asked by a friend who'd just taken delivery of a very nearly new 10m Danish trimaran to help him navigate it from The Solent to Oban, for the Scottish Islands Peaks Race. Hugely generous in many ways, he was extremely penny-pinching in others, but when he handed me a plastic folio containing a 'wet pulp' of the charts he'd used the previous year, still soaked and just a soggy mush, it was clear he rather expected meticulous me to fork out for new charts.....

I decided that was an expensive presumption too far, so turned up with my nav bag full of 'nav stuff'....and off we went. He left the actual nav to me.....

I didn't open a chart or raise a pencil ( that he saw ) all the way down SW, then round the corner, and all the way up the Irish Sea. I had a couple of Passage Plans which he saw and peered at, and a well-worn copy of NP109 NW Europe Standard Nautical Charts Catalogue which I would open at the relevant - but very small scale - page from time to time.... gaze around the horizon, tap the paper with a forefinger, plonk a 'Fix' symbol and time onto the page..... then suggest a course correction and offer an ETA for the next significant waypoint.

Of course I was right, of course he had no idea what technique I was using, and of course he had no intention of questioning my competence for he knew he'd then have to do the nav himself..... with his useless soggy charts.

He was sweating quite a bit as we passed along the Antrim coast, despite the tide-set, and even up into the Sound of Jura.... but by golly he was sweating blood as we neared the roiling entrance to The Gulf of Corrievrecken, the notorious Dhorus Mhor - and beyond, the sluicing, swirling tight rocky passage of the Sound of Luing..... which he feared.

"Are you still 'all right' with the navigation? Have you been here before?" he finally spluttered. "Yes, I'm quite happy," I replied. "I know where we are, I think" naming some of the craggy islands around. "And we're going up through there," I added, waving in a general way at the barrier of rocky islets up ahead. He wasn't reassured in the least.....

He wasn't to know, for he hadn't studied the large-scale chart in detail ( as I had ) that one could pass easily either side of Fladda with its quite conspicuous sector light, or east of Dubh Sgeir, or even west of nearby Belnahua isle..... easily, that is, with a following tide, for the stream there runs at over 7 knots at times. I didn't mention the shallow patches just to the south - he didn't 'need to know', and we had a trimaran - but he certainly 'clocked' the impressive boils, swirlies and upwellings there.

He wasn't to know I DID have the latest large-scale chart BA2326 scale 1:25000 marked-up, folded and ready but hiding in my sleeping bag with all the pilotage planned and noted in the end-papers of a couple of paperbacks I had with me. Besides which, as I told him later, I had done a V-Force style 'route study' and memorised all the necessary courses, hazards, clearing bearings, tidal info etc. 'for the whole route' - and Plans B and C. Whether he believed me or not is quite another story.

Of course we shot through, 'cork out of a bottle' style, and on we flew into Oban Bay and a mooring at the club there. He was certainly glad to get ashore....and beetled off to Nancy Black's chandlery in town, where he bought himself all the new charts he could carry!

:cool:
 
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AntarcticPilot

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Tilman used a far quicker and simpler method - one that works for any latitude for which you have a paper chart of a similar scale. He had the small scale chart of the North Sea as we had sailed up it.

Prick through the latitude and longitude lines, turn the chart over, and draw them using a pen and the parallel rulers. Name them for the longitudes that you want to sail through. Using the Light List, mark the lights and their characteristics. Result, in this case, a chart of the Irish Sea. Navigate to keep on the right side of the lights and a safe distance off.
Yes, that works. Shifting longitude like that is fine on normal aspect Mercator (won't work on Transverse Mercator). What doesn't work (and it once gave me a great deal of trouble!) is to take a plotting sheet at half the desired scale and relabel the latitude lines at twice the original interval. The relationship between latitude and the y-coordinate is non-linear (extremely so in the polar regions), so it fails in ways that are difficult to handle. Longitude is easy; it's linear with the x-coordinate, but latitude is not.
 

AntarcticPilot

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'A long time ago on a passage far, far away'.....

.....I was asked by a friend who'd just taken delivery of a very nearly new 10m Danish trimaran to help him navigate it from The Solent to Oban, for the Scottish Islands Peaks Race. Hugely generous in many ways, he was extremely penny-pinching in others, but when he handed me a plastic folio containing a 'wet pulp' of the charts he'd used the previous year, still soaked and just a soggy mush, it was clear he rather expected meticulous me to fork out for new charts.....

I decided that was an expensive presumption too far, so turned up with my nav bag full of 'nav stuff'....and off we went. He left the actual nav to me.....

I didn't open a chart or raise a pencil ( that he saw ) all the way down SW, then round the corner, and all the way up the Irish Sea. I had a couple of Passage Plans which he saw and peered at, and a well-worn copy of NP109 NW Europe Standard Nautical Charts Catalogue which I would open at the relevant - but very small scale - page from time to time.... gaze around the horizon, tap the paper with a forefinger, plonk a 'Fix' symbol and time onto the page..... then suggest a course correction and offer an ETA for the next significant waypoint.

Of course I was right, of course he had no idea what technique I was using, and of course he had no intention of questioning my competence for he knew he'd then have to do the nav himself..... with his useless soggy charts.

He was sweating quite a bit as we passed along the Antrim coast, despite the tide-set, and even up into the Sound of Jura.... but by golly he was sweating blood as we neared the roiling entrance to The Gulf of Corrievrecken, the notorious Dhorus Mhor - and beyond, the sluicing, swirling tight rocky passage of the Sound of Luing..... which he feared.

"Are you still 'all right' with the navigation? Have you been here before?" he finally spluttered. "Yes, I'm quite happy," I replied. "I know where we are, I think" naming some of the craggy islands around. "And we're going up through there," I added, waving in a general way at the barrier of rocky islets up ahead. He wasn't reassured in the least.....

He wasn't to know, for he hadn't studied the large-scale chart in detail ( as I had ) that one could pass easily either side of Fladda with its quite conspicuous sector light, or east of Dubh Sgeir, or even west of nearby Belnahua isle..... easily, that is, with a following tide, for the stream there runs at over 7 knots at times. I didn't mention the shallow patches just to the south - he didn't 'need to know', and we had a trimaran - but he certainly 'clocked' the impressive boils, swirlies and upwellings there.

He wasn't to know I DID have the latest large-scale chart BA2326 scale 1:25000 marked-up, folded and ready but hiding in my sleeping bag with all the pilotage planned and noted in the end-papers of a couple of paperbacks I had with me. Besides which, as I told him later, I had done a V-Force style 'route study' and memorised all the necessary courses, hazards, clearing bearings, tidal info etc. 'for the whole route' - and Plans B and C. Whether he believed me or not is quite another story.

Of course we shot through, 'cork out of a bottle' style, and on we flew into Oban Bay and a mooring at the club there. He was certainly glad to get ashore....and beetled off to Nancy Black's chandlery in town, where he bought himself all the new charts he could carry!

:cool:
Ever considered that you might be just a teensy, weensy bit evil :devilish::devilish:? Mind I reckon the owner deserved it!

As you say, as long as you miss the rocks you're generally OK in the Sound of Luing - but it doesn't look like you are!
 

DownWest

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Mentioned this before, but, when very young, I was tasked to get a Fairey Atalanta back from Northern Sardinia. Not bonkers enough to sail it via the Atlantic, I built a trailer and found an ex military 4x4 to tow it. Then, trained down to Rome and the ferry to the island. Very scarey bus ride to the north. Spent 10 days getting the boat ready( it had been sunk, not mentioned..) Then set off for St Tropez. No charts, due to the sinking (motor u/s too) But blagged a school atlas and drew up the area on a big sheet of paper. Long and Lat lines, then squiggled in the bits like Corsica. We had a leaky RAF compass in a box and a Walker log. So DR was the only way.
After several days, I thought we must be close, then, in the morning mist, saw the bit I had been aiming for. Not bad for an amateur.. That was in '69.
 

zoidberg

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Ever considered that you might be just a teensy, weensy bit evil :devilish::devilish:?

I can do evil. It's a lifestyle choice.... :giggle:

As for 'missing the rocks'.... that was my dayjob for HMQueen.

I'm likely the only ex-RAF nav who, with his long-suffering pilot, had an 'Airmiss' filed against him by the Captain of a Polaris submarine....sneaking out of the Lower Clyde in fog..... er, 'somewhat reduced visibility'..... doing 360kts at 'cough, cough' altitude .....several white things whipped past the right wingtip.
We found out an hour or so later during a stand-up interview at RAF Kinloss, our destination for the night, that MoD(Navy) had been raising all kinds of hell with MoD(AirForce) down in London, and that the noise could be heard in in the Nimrod Station Commander's office up there in Morayshire.

After a very competent and professional bollocking from a Very Senior Officer i/c the Nimrod Fleet, it emerged that the sneaky Polaris lot had not told anyone that they'd be passing that way, so we didn't know to avoid them. The initial threat made to impound our aircraft and make us walk home ( Cornwall! ) was tempered after a few minutes to "I expect there will be a bill forwarded for cleaning of some RN Officers' underwear.... Right, lads, the O'Mess bar will be open now. Come and have a beer and tell me it all again."

:)
 

AntarcticPilot

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I can do evil. It's a lifestyle choice.... :giggle:

As for 'missing the rocks'.... that was my dayjob for HMQueen.

I'm likely the only ex-RAF nav who, with his long-suffering pilot, had an 'Airmiss' filed against him by the Captain of a Polaris submarine....sneaking out of the Lower Clyde in fog..... er, 'somewhat reduced visibility'..... doing 360kts at 'cough, cough' altitude .....several white things whipped past the right wingtip.
We found out an hour or so later during a stand-up interview at RAF Kinloss, our destination for the night, that MoD(Navy) had been raising all kinds of hell with MoD(AirForce) down in London, and that the noise could be heard in in the Nimrod Station Commander's office up there in Morayshire.

After a very competent and professional bollocking from a Very Senior Officer i/c the Nimrod Fleet, it emerged that the sneaky Polaris lot had not told anyone that they'd be passing that way, so we didn't know to avoid them. The initial threat made to impound our aircraft and make us walk home ( Cornwall! ) was tempered after a few minutes to "I expect there will be a bill forwarded for cleaning of some RN Officers' underwear.... Right, lads, the O'Mess bar will be open now. Come and have a beer and tell me it all again."

:)
Better an AirMis than an Accident Investigation!
 

glynd

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I liked one of the details from the Falklands / vulcan raids.
They didn’t have any charts of the southern Atlantic, so they used a northern hemisphere one and flipped it upside down
 

zoidberg

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This leads me to think that the vast pile of out of date Admiralty Charts under the bunk mattresses will not be thrown out.

I have a double handful of those.... including some that are in black and white, with little sketches along the bottom. ;)
 

xyachtdave

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I'll offer this with great respect to the much more competent navigators than I on YBW.

Yes I think could find my way about without the reassuring screen at my chart table but I reckon I wouldn't enjoy my sailing as much.

I go sailing in my free time, not navigating.

Passage planning reminds me of my not yet started/done homework on Sunday evenings as a child.....

The theme tunes to The Last of the Summer Wine, Open All Hours and Songs of Praise still bring a shudder to my spine!
 

LadyInBed

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I go sailing in my free time, not navigating
Same here, sail for the freedom and to visit places. Navigation is necessary to get you there, but now with the advent of the chart plotter, the navigation bit can almost be reduced to - set a wp and tell the autopilot to goto wp, then get on with trimming sails, enjoy the tranquility and maybe do a bit of fishing for dinner.
 
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