halcyon
Well-Known Member
Falmouth harbour ( including Carrick roads ) is reputed to be the third largest natural harbour.
Brian
Second Biggest Natural Harbour in the World
- Thread starter Romeo
- Start date
Falmouth harbour ( including Carrick roads ) is reputed to be the third largest natural harbour.
Brian
BlackPig
N/A
The Clyde is big. Including Loch long etc. Why is it not on the list must be a lot bigger than Poole.
AntarcticPilot
Well-Known Member
And, of course, it is ALL (north of Arran, anyway) officially a port.
Bru
Well-Known Member
Wot he said
Seajet
...
Me too, even if 99% of it is too shallow for Dylan's Duck Punt !
johnalison
Well-Known Member
I'm sure Falmouth was the second largest when I were a child, to Melbourne. But then, it may have shrunk or new lands discovered.
Birdseye
Well-Known Member
What about MIlford Haven?
RichardTaylor
Well-Known Member
Would the Med would surely qualify as a harbour? (being an inlet off the Atlantic Ocean)?
Coaster
Well-Known Member
The Milford Haven waterway is roughly the same area as Poole Harbour. Look at them on mapping of the same scale.
As said by others, the answer to the OP's question depends on arbitrary definitions.
Perhaps we could make a start in the definitions by stipulating the bodies of water must have been called 'Port', 'Harbour', 'Haven' or the equivalent, for at least 100 years, and that 'Bay', 'Cove' etc. are excluded.
alant
Well-Known Member
Seattle/Tacoma is pretty large.
GrahamD
Well-Known Member
The second immutable childhood truth about Poole Harbour is that the total length of the harbour's coastline is 100 miles. Life was so much more certain then.
Seajet
...
I'd have thought Poole's circumference must be a fair bit more than that, but I'm only guestimating as I'm not based there, just enjoy visiting.
AntarcticPilot
Well-Known Member
Sigh!
I'm afraid that any geographer will tell you that the length of any coast is infinite, or at least unmeasurably long. Saying "such and such a coast is 100 miles long" is meaningless unless you state the scale and accuracy with which you measure. The same goes for islands in an archipelago; there are infinitely many, unless you add criteria like "big enough for a man and a goat". A further complication for marine coasts is that the answer is different moment by moment as the tide changes!
A very interesting read on this subject is "The Fractal Geometry of Nature" by Benoit M Mandelbrot (http://www.amazon.co.uk/Fractal-Geometry-Nature-Benoit-Mandelbrot/dp/0716711869), but be prepared for moderately hard maths.
Seajet
...
Sigh,
I was quite obviously talking about the circumference of a clearly defined harbour, not the planet it's attached to...
I was quite obviously talking about the circumference of a clearly defined harbour, not the planet it's attached to...
alant
Well-Known Member
Are you using chart datum?
Seajet
...
Alant,
no, Sod all that tecnology and Cartography nonsense; I was planning a sponsored trip by a thousand Duck Punts each equipped with a solar powered depth sounder, waterproof chart & crayon, calibtrated depth stick and support boat but now you've spoiled the surprise so we'll have to do it the old way, with lifting keels and taking a note when and where we come to a ginding halt !
no, Sod all that tecnology and Cartography nonsense; I was planning a sponsored trip by a thousand Duck Punts each equipped with a solar powered depth sounder, waterproof chart & crayon, calibtrated depth stick and support boat but now you've spoiled the surprise so we'll have to do it the old way, with lifting keels and taking a note when and where we come to a ginding halt !
AntarcticPilot
Well-Known Member
What I said applies to ANY coastline, be it of a harbour, lake or whatever. It might (but only might!) not apply to a man-made harbour with engineered walls, but any natural coastline is infinitely (or at least, unmeasurably) long. The reason is because natural coastlines are fractal in nature; that is, if you measure the length with different sized rulers, you get different answers. The shorter the ruler, the longer the length, down to the sub-atomic scale (where things break down and go quantum).
Here's a piece I once wrote about the problem:
In the mapping unit, we are often asked to quantify geographic objects. Questions like “How big?” or “How far?” we generally can answer. But there is a class of question that can’t be answered in a straightforward manner. “How long?” and “How many?” frequently don’t have a meaningful answer without additional information. I’ve just been asked “How many islands are there in the South Georgia archipelago?” Well, our spatial database says 1,025 – but this figure is meaningless.
The problem is that most natural objects have fractal dimensions. Think of it this way. If I digitise the coastline of South Georgia using an image with a resolution of (say) 60m, it means the smallest object I can see is ~100m across. Groups of islands will get merged into one object and isolated small islands won’t be visible at all. But if I increase the image resolution the number of separate islands goes up. And so it goes on, down to the microscopic scale. Therefore any number for “How many islands?” has to be qualified – e.g. “How many islands larger than x square metres?” Even then, closely spaced islands may not be distinguished. There is also the problem that the answer changes according to the tide!
The length of coastlines suffers from exactly the same problem – the higher the resolution, the longer the coastline. Indeed, Benoit Mandelbrot of fractal fame has shown that the measured length of any coastline approaches infinity as the resolution increases! So fractals aren’t just the pretty pictures you see in books about chaos – they have a real and practical impact on what is measurable, and what is not.
Seajet
...
Seems pretty simple to me, I'd just measure around the rim.
If really bothered a retired bloke with a pedometer and GPS would do, no need to fund a classful of irritating graduates on a year long thesis !
If really bothered a retired bloke with a pedometer and GPS would do, no need to fund a classful of irritating graduates on a year long thesis !
Kelpie
Well-Known Member
Seems pretty simple to me, I'd just measure around the rim.
If really bothered a retired bloke with a pedometer and GPS would do, no need to fund a classful of irritating graduates on a year long thesis !
What is 'the rim' though??
AntarcticPilot
Well-Known Member
Precisely!