Guess the Place

[Dave Smith]

My pleasure Martin . That is why I like reading auto & biographies, a lot of people have had most interesting lives. A love of the sea is in the blood I think, so sad for you that it was not to be. When I was at school, scouts, ATC, RAF, ALL were Imperial Units- so no confusion. Even threads were BA, Whitworth BSF, BSC &  BSP ( British!). All gone now, although Pipe stayed for some time along with the diameter of iron pipe- not Napolionic! I don't know what it is now? Way off thread( pardon the pun) I'm afraid but maybe more of KHF's than John & I find it all interesting?

[MartinR]

Hi Shoot99.  Interesting to compare that to today's charts.  It really shows how the sand and mud moved in the estuary over the last half century.

[shoot999]

I don't know why but creeks always give me the jitters.  What lies beneath and all that  .   Looking at the chart I think I would find navigating waters like that a nightmare.

Not exactly plain sailing once you left the creeks and rivers John.  This was what I was working with during the sixties and seventies.   

[grandarog]

John,Its the height of the bit of the bottom that is above water level when the Tide goes out. There's a lot showing around the shores of Upchurch and Lower Halstow at Low Tide.

[John Walker]

More fascinating information from you Martin.  A great and varied career.   So sorry to hear of your health problems.

A question from me.  What is meant by 'Drying Height'.

[MartinR]

You were right, a fathom is 6'.  However for most practical purposes that's 2m for those who prefer Napoleonic units to Christian ones.*

• 4₅ = 4.5 m
• 2₆ = 2.6 m drying height.
• 42 = 42 m, note that the 2 is full size.

Heights and depths are referenced to the Lowest Astronomical Tide (LAT) which is the lowest that the tide can get purely due to astronomical effects, though weather may take it lower.  The predicted low tide at 2320 today is 1.5m, so you need to add that to the charted depths.
A very interesting set of guesses about my career!  After a short period in Middlesbrough Public Libraries I worked for 5 years at Whitley Bay High School as a lab technician.  Most of my life though has been working with computers, rising from operator through system programmer to system management.  Virtually all the work has been on behalf of the MoD, so any more information is inappropriate here.  We were taught about maps at school, in the scouts, ATC and OTC.  I've studied a bit about surveying just for interest.  I seriously considered the Senior Service when at school, but there were questions about my health.  I've tried to spend time on boats as much as possible, without a lot of success until I was made redundant when I bought an old yacht.  I've trained as Day skipper (theory and practical) and Yachtmaster (theory) but can't really take it further due to failing health.  Thinking me RN!  That's must rank as today's best complement. 




*Sarcy comment nabbed from "The Model Engineer".

[John Walker]

Was it a NatWest bank? Just guessing as you searched those for the Gillingham GTP.

Not a NatWest but I like your thinking 


Try HSBC ...

[Dave Smith]

Martin. Yes, very interested particularly as there seems to be a bit of a mish mash of units used. And even these seem a bit inconsistent e.g. 1 fathom I always thought was 6 ft. but you say, or 2 m? And the water depth on that chart is in 1/10's of a meter. Very confusing unless you are fully aware of all the different uses! I thought at first that your knowledge of maps was due to being a surveyor in your native Yorkshire but your photo leads me to think Royal Navy, ending up at HMS Pembroke & settling in Rochester?   

[johnfilmer]

Was it a NatWest bank? Just guessing as you searched those for the Gillingham GTP.

[John Walker]

That also looks like a bank somewhere.

It was a bank once upon a time.

[MartinR]

That also looks like a bank somewhere.

[John Walker]

I don't know why but creeks always give me the jitters.  What lies beneath and all that  .   Looking at the chart I think I would find navigating waters like that a nightmare.


Right - next GTP.


Where is this door?

[MartinR]

OK, a bit of technical information on charts here, just in case anyone is interested.:

A chart will always show the latitude and longitude since that is how navigation is done.  It is crucially important that the latitude scale running down both sides is used and never the longitude scale across the top and bottom.  The lines of longitude (NS) converge at the poles and so will never be 60 nm apart except at the equator.  Most charts will not show nautical miles, you just read from the longitude scale.  Furthermore, the scales are in degrees, minutes and decimals of a minute.  Positions are given in this way too.  One minute is a nautical mile, 1/10 of a minute is a cable's length and 1/1000 of a minute is a fathom (6' or 2m).  For instance one of the navigation buoys in the mouth of the Medway is at 51°25'.813N, 000°43'.945E.  Note also that the latitude is always given as two figures (ie 00 to 90) whereas the longitude is given as three figures (ie 000-180).

See any book on navigation at Day Skipper level or above.

I've enclosed a tiny part of one chart showing Walton Creek, Essex.  Notice on the right hand side 51°52'N and 51'.5.  The second, lower value is minutes only and the "ticks" are tenths of a minute, near enough 600'.  Notice also the ticks across the bottom are much closer than down the sides.  The figures in the water are depths in metres and tenths (in smaller type).  Underlined values are drying heights.

[Dave Smith]

Thanks from me too Martin. Interestingly, where I worked in 1960+, the Research manager was on the British Metrics Committee, changing everything to SI units. He said at that time that Meters & Millimeters were the standard, not Centimeters. Of course the nautical mile ( knot = n/m per hour)is relative to the division of the earth into degrees, minutes & seconds, so is more logical than meters.

[John Walker]

Really interesting info MartinR. You obviously know your maps. Thank you.