Call yourself a navigator?'

scotty123 said:
Wasn't it all 'aim for a landfall' (not a specific harbour), then turn port/starboard to get to your destination?
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I remember when I was doing my cadetship as a deck officer being advised that Navigation was not a precise science so it was not necessary to employ the bendy parallel rulers to get the perfect fix. On long passages we always took noon sites and we had to practice starsites and azimuths as part of our training. All worked out long hand with 5 figure logs and a "Sights" book in which I had prepared a proforma sheet to use to capture everything on. Sometimes it was pretty good, other nights the lines were all over the place
 
Minn said:
I most certainly have seen a small(ish) boat navigated accurately with a sextant, a deck watch, a Walker Excelsior log and a lead line, for several thousand miles including little known coastlines.

https://comlay.net/tilman/voyages/1974-spitzbergen/
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FWIW I've read all Tilman's sailing books and met Bob Comley and seen him talk. Astonishing adventures. (Well for Tilman I guess it was an astonishing way of life.) FWIW greatest respect to you all from this weekend sailor.
 
CamR said:
I remember when I was doing my cadetship as a deck officer being advised that Navigation was not a precise science so it was not necessary to employ the bendy parallel rulers to get the perfect fix. On long passages we always took noon sites and we had to practice starsites and azimuths as part of our training. All worked out long hand with 5 figure logs and a "Sights" book in which I had prepared a proforma sheet to use to capture everything on. Sometimes it was pretty good, other nights the lines were all over the place
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Our company and I suspect many others navigated “according to Hoyle”, as you describe, but had “standard passages” which were all built around making safe landfalls on prominent features. We had to re-think these after GPS. Not only were they adding miles but on one occasion when we were trialling one man bridge operation the Mate dozed off after a full day’s cargo work and made a rather too perfect landfall just short of the lighthouse he was aiming for. It wasn’t a disaster but it was embarrassing and the end of one man bridge operations...
 
I’ve just done a passage from Plymouth to the Solent.

About 3 hours after passing south of Portland Bill I went below to complete the log. The fairly old Garmin plotter at the nav station showed the boat icon about a mile east of the entrance to Weymouth. In my 25 years as a recreational sailor this was my first witness of a GPS failure.

The boat had another Garmin plotter near the helm and this was showing correct. When on others’ boats, I carry a Lenovo Tab with VMH Raster charts. With 3 of us on board, including the ubiquitous Dumb Phones, we had access to GPS on 7 devices.

I still used a hand written night pilotage plan for entrance through Needles Channel.

Upon arrival and after turning the power from the panel off and on again, the plotter in question burst back into life. Earlier, it had shutdown using its on-off switch but then refused to respond any further.
 
davidjackson said:
I’ve just done a passage from Plymouth to the Solent.

About 3 hours after passing south of Portland Bill I went below to complete the log. The fairly old Garmin plotter at the nav station showed the boat icon about a mile east of the entrance to Weymouth. In my 25 years as a recreational sailor this was my first witness of a GPS failure.

The boat had another Garmin plotter near the helm and this was showing correct. When on others’ boats, I carry a Lenovo Tab with VMH Raster charts. With 3 of us on board, including the ubiquitous Dumb Phones, we had access to GPS on 7 devices.

I still used a hand written night pilotage plan for entrance through Needles Channel.

Upon arrival and after turning the power from the panel off and on again, the plotter in question burst back into life. Earlier, it had shutdown using its on-off switch but then refused to respond any further.
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"Pilotage plan"?
Don't you just use the sectored lights of the Needles & Hurst LH's?
 
Mark-1 said:
FWIW I've read all Tilman's sailing books and met Bob Comley and seen him talk. Astonishing adventures. (Well for Tilman I guess it was an astonishing way of life.) FWIW greatest respect to you all from this weekend sailor.
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Reading about the voyage to Svalbard reminds me of my own early career - I helped to produce one of the earliest accurate maps of NordAustlandet, and worked on Svalbard through the 80s - my first trip there was in 1972!
 
AntarcticPilot said:
Reading about the voyage to Svalbard reminds me of my own early career - I helped to produce one of the earliest accurate maps of NordAustlandet, and worked on Svalbard through the 80s - my first trip there was in 1972!
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Incredible, I suspect there was a bit more ice there back then.
 
AntarcticPilot said:
Reading about the voyage to Svalbard reminds me of my own early career - I helped to produce one of the earliest accurate maps of NordAustlandet, and worked on Svalbard through the 80s - my first trip there was in 1972!
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Did you re-survey Hecla Cove? I ask because I particularly recall the legend "Surveyed by Lt Parry, RN, 1827" on the chart we used. It was quite something to anchor in Parry's cove, named after his ship, and to do so using his chart!
 
Minn said:
Did you re-survey Hecla Cove? I ask because I particularly recall the legend "Surveyed by Lt Parry, RN, 1827" on the chart we used. It was quite something to anchor in Parry's cove, named after his ship, and to do so using his chart!
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No, we didn't - the main island, Vest Spitzbergen, was well mapped (by Arctic standards!) by the Norsk PolarInstitutt. They didn't have aerial cover of NordAustlandet, where we were going to carry out geophysical surveys. That was the impetus for our mapping.
 
A Norsk PolarInstitutt vessel which I would describe as a slightly glorified sealer, much like the Sysselman’s yacht, but with two small choppers on the after deck (it was too small for them to land or take off from - they must have been put over the side with a derrick) came into Hecla Cove whilst we were there but they didn’t seem to be surveying anything. Anyway, Parry’s work was good enough (by Arctic standards!).
 
I remain intrigued by the techniques used by then-Major Ewen Southby-Tailyour RM when he surveyed the coves and inlets around much of The Falkland Islands in about 1979.
His notes formed the basis of his pilotage book 'Falkland Islands Shores', with an important supplement by Peter and Annie Hill.
 
zoidberg said:
I remain intrigued by the techniques used by then-Major Ewen Southby-Tailyour RM when he surveyed the coves and inlets around much of The Falkland Islands in about 1979.
His notes formed the basis of his pilotage book 'Falkland Islands Shores', with an important supplement by Peter and Annie Hill.
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The Hills' supplement is a free download from the RCC Pilotage Foundation, and E S-T writes that he did his surveying from a dinghy, a warship, a yacht.. and by swimming!
 
Minn said:
Did you re-survey Hecla Cove? I ask because I particularly recall the legend "Surveyed by Lt Parry, RN, 1827" on the chart we used. It was quite something to anchor in Parry's cove, named after his ship, and to do so using his chart!
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Just to expand on my brief earlier answer. In remote regions, it is most unlikely that terrestrial topographic mapping would be done by ground parties; it simply isn't cost-effective. What happens (and this was our procedure in the Antarctic) is that once an area has been identified as requiring mapping, the first part would be to obtain a number of ground control points (GCPs) - these days, by sending a field party out with a survey-grade GPS; in past times (pre 1980s - Transit was used before GPS; we used Transit in 1983!) this would be a trigonometric survey tied either to a pre-existing survey network or to astronomical fixes. In parallel, there would be an airborne photographic survey acquiring photographs with sufficient overlap for photogrammetry (at least 50%; usually more). The map would then be made using photogrammetric techniques to measure elevation and plan position - these days (since 2000) it would be done using a suitably equipped PC; in days of old by using a specialized photogrammetric plotter. The number of ground control points required isn't all that high; the main criterion is that they be on points readily identified on aerial photos. The point is that GCPs need not be on points such as peaks that are identifiable at great distances horizontally as in conventional survey, so the GCPs for aerial photography can be acquired without heroic efforts to scale inaccessible peaks etc.

To the best of my knowledge most of the rocky islands of Svalbard have been mapped using these techniques; NordAustlandet and Kvitoya are the exceptions because photogrammetry doesn't work on uniform snow-covered surfaces such as the icecaps of those two islands. These days satellite techniques are used, which don't work so well on the steeper terrain of the other islands.

Using this technique means that large areas can be mapped without excessive investment in field parties - a few hours flying time can map hundreds of square kilometres of ground, and most of the work takes place in a nice warm office! And the ground party can usually do it's work in a few days of workable weather, rather than months.

Hydrographic survey is most unlikely to happen at all in such areas except on an opportunistic basis by expeditions such as Parry's. There simply isn't any impetus for routine surveying of remote areas; commercial or naval vesssels don't go there, and people such as Tilman are presumed to go at their own risk! However, Tilman should have had access to perfectly adequate topographic maps of everywhere except NordAustlandet, and HinlopenStretet was also pretty well mapped - it was the parts of NordAustlandet further east that were not well mapped. We had adequate maps of VestSpitzbergen in 1972!

Apologoies for my spelling of Norwegian names - done from memory, so may be faulty!
 
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AntarcticPilot said:
Just to expand on my brief earlier answer. In remote regions, it is most unlikely that terrestrial topographic mapping would be done by ground parties; it simply isn't cost-effective. What happens (and this was our procedure in the Antarctic) is that once an area has been identified as requiring mapping, the first part would be to obtain a number of ground control points (GCPs) - these days, by sending a field party out with a survey-grade GPS; in past times (pre 1980s - Transit was used before GPS; we used Transit in 1983!) this would be a trigonometric survey tied either to a pre-existing survey network or to astronomical fixes. In parallel, there would be an airborne photographic survey acquiring photographs with sufficient overlap for photogrammetry (at least 50%; usually more). The map would then be made using photogrammetric techniques to measure elevation and plan position - these days (since 2000) it would be done using a suitably equipped PC; in days of old by using a specialized photogrammetric plotter. The number of ground control points required isn't all that high; the main criterion is that they be on points readily identified on aerial photos. The point is that GCPs need not be on points such as peaks that are identifiable at great distances horizontally as in conventional survey, so the GCPs for aerial photography can be acquired without heroic efforts to scale inaccessible peaks etc.

To the best of my knowledge most of the rocky islands of Svalbard have been mapped using these techniques; NordAustlandet and Kvitoya are the exceptions because photogrammetry doesn't work on uniform snow-covered surfaces such as the icecaps of those two islands. These days satellite techniques are used, which don't work so well on the steeper terrain of the other islands.

Using this technique means that large areas can be mapped without excessive investment in field parties - a few hours flying time can map hundreds of square kilometres of ground, and most of the work takes place in a nice warm office! And the ground party can usually do it's work in a few days of workable weather, rather than months.

Hydrographic survey is most unlikely to happen at all in such areas except on an opportunistic basis by expeditions such as Parry's. There simply isn't any impetus for routine surveying of remote areas; commercial or naval vesssels don't go there, and people such as Tilman are presumed to go at their own risk! However, Tilman should have had access to perfectly adequate topographic maps of everywhere except NordAustlandet, and HinlopenStretet was also pretty well mapped - it was the parts of NordAustlandet further east that were not well mapped. We had adequate maps of VestSpitzbergen in 1972!

Apologoies for my spelling of Norwegian names - done from memory, so may be faulty!
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Thanks for taking the trouble to post this, really interesting.
 
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