Goodwin Sands

[Hallberg-Rassy]

Any sign of line or net entanglement? Some of the cuts & injuries in those Ocean Conservation Namibia's videos were harrowing. A single of fishing line cutting right through the seals' flesh.

If you are landing everything becomes rather more critical, and you would need to be confident that you weren't going to be 'parking' your boat on either debris that could damage it or a severe slope that could make it fall over.

Yes, my question was what happens when the tide comes in and the sand starts to turn?

 

[LittleSister]

Yes, my question was what happens when the tide comes in and the sand starts to turn?

I don't understand what you mean by 'the sand starts to turn'.

 

[Hallberg-Rassy]

I've read it does not react like a normal beach but that some or all of it becomes like quicksand.

 

[Gary Fox]

There's an interesting book called 'Heroes of the Goodwin Sands', about historic rescues over the last century or more.
Nigel Calder wrote a book about the channel area, which has some tales, and there's another book called 'The Narrow Sea' with some more info. I'm fascinated by the area, partly because one night I nearly got wrecked, and probably killed, on the Goodies..quite a few years ago...
Really weird things happen due to the vertical circulation of millions of tons of sand, containing the debris of thousands of wrecks since the dawn of seafaring.
. One spooky one I heard was thousands and thousands of sheep bones suddenly appearing on the surface, from an old livestock carrier which went aground. There are literally huge ships circulating down there, and masts appear and disappear. It is a fascinating place. A couple of years ago a WW2 German aircraft was salvaged, there will be more.

 

[Gary Fox]

I've read it does not react like a normal beach but that some or all of it becomes like quicksand.

Yes so I have read, and timing and local knowledge are vital for the games of cricket and so on.

 

[Tomahawk]

Indeed it can.
Once it is super saturated the sand particles become partially buoyant. The mass becomes semi liquid whan agitated.
The practical effect is that a vessel settles on the liquid sand and under its weight begins to sink into the sand. But once the movement stops at low water or hard aground, the sand settles in s potentially vice grip holding the keel in ds the tide starts rising.

 

[Flynnbarr]

There must be a way through the sands ?.......I was trundling down to Dover and saw a sailing boat go straight across them a few years back.

 

[Tomahawk]

There is the Gull Stream between the large banks and the shallow off the Pegwell Bay. Well bouyed and safe
Or go down the inside via B2 and stay close to the beach

You could go through the Kellet Gut but why would you want to?

 

[C08]

Indeed it can.
Once it is super saturated the sand particles become partially buoyant. The mass becomes semi liquid whan agitated.
The practical effect is that a vessel settles on the liquid sand and under its weight begins to sink into the sand. But once the movement stops at low water or hard aground, the sand settles in s potentially vice grip holding the keel in ds the tide starts rising.

In the Porthmadog Yacht club a number of us were talking about the mostly nasty bars in Cardigan Bay and which were the worst i.e Porthmadog, Aberdovey, Barmouth, Cardigan etc. One of the older memebers recounted the tale of the twin keel yacht that ran out of water on Porthmadog Bar so when well dried out ran out the anchor with lots of chain and walked off to the yacht club to have apint while awating to the tide to refloat the boat. Not at all concerned as winds were light and on shore. Anyway one of the club members took him back in a dinghy and the boat was gone presumably sunk and swallowed up by the sands that according to tales of old had consumed many boats in the past.
At the time despite all the protestations of the truth of the tale from a number of older club members I was very sceptical about the "sands swallowing up a yacht".
When I was a little older and wiser having had worrying times having dried out I am now inclined to believe the sand becoming liquified by the returning tide. Once at Porthmerion where the boat (an old heavy Macwester 26) dried out very nicely on the sand near the beach concrete feature but as the tide returned the boat sank so that the sand was level with the side decks before she came up and floated. Another time in the Mersey Estuary near Spike Island the returning tidal bore knocked the boat over to about 45 degrees and I was very concerned the boat would go over before she floated.
I am much less sanguine about drying out nowadays even with a cat!

 

[LittleSister]

Once it is super saturated the sand particles become partially buoyant. The mass becomes semi liquid whan agitated.
The practical effect is that a vessel settles on the liquid sand and under its weight begins to sink into the sand. But once the movement stops at low water or hard aground, the sand settles in s potentially vice grip holding the keel in ds the tide starts rising.

I don't believe that.

 

[Hallberg-Rassy]

CO8,

Truth be, that's more what I was expecting. Especially the fear of one keel dropping first, and shifting sands catching the sidedecks.

Unless the Welsh have a habit of stealing boats from half-cut English sailors and spinning such yarns!

Frightening really.

 

[Bru]

I don't believe that.

Believe it! Tomahawk is right

Doesn't just happen on the Goodwins (once known as Ye Shippe Swallower!) but elsewhere too

The sailing barge Defence went on the Buxey sands off Essex in bad weather late 1800s. Went they sent out to salvage her 48 hours later only her mast was showing above the sand. She's still there, somewhere

 

[Tomahawk]

 

[LittleSister]

I believe liquefaction happens. I don't believe liquefaction happens when the tide's going out, and then becomes solid when the tide is coming in.

The strange thing is that boats float on liquids!

 

[Keith 66]

Liquefaction happens in all sorts of soils, common in earthquakes & plenty of videos on you tube to attest to that. As to sandbanks a couple of bloke i used to know were out off old Leigh near the ray & got caught out in a heavy thunderstorm, one told me the rain was so heavy that the sand became liquid like quicksand & they realised that if they stopped moving they were in deep trouble.
The other place where this is common is Morecambe bay, my cousin kept a fishing boat off the promenade & she sank in a storm back in the early 80's, sand swallowed it, she has popped up a couple of times only to disapear again after a few days.

 

[Cantata]

Liquefaction is a useful asset employed by CG rescue teams getting folk out of the mud. Teams have (or certainly had in my day) fire extinguishers filled with water, with long lances on the hose to inject water round a trapped person's legs so they can be pulled out more easily.

 

[38mess]

Is this why a lifeboat comes out now if a boat goes around on sand? I wonder

 

[Hallberg-Rassy]

Example of liquidification

I have no idea of the science of what is going on in that video (I note how far the tide is out), but I have to say at certain points it reminded me of an old girlfriend I had.

And that was a terrible mistake, and messy to extract myself from too.

 

[Bru]

I believe liquefaction happens. I don't believe liquefaction happens when the tide's going out, and then becomes solid when the tide is coming in.

The strange thing is that boats float on liquids!

It can happen anytime but it's most likely to happen when the tide is rising and the sand becomes waterlogged. Then all it takes is agitation, such as a boat pounding even gently as it floats to start the process

As the tide goes out and the boat begins to settle the sand is still saturated and down you go. Then as the water drains from the sand it solidifies

Where it gets interesting is that whilst you might think that the boat would float to its marks in the liquefied sand, it doesn't. It keeps on getting sucked down. I don't claim to understand this process but it is a well documented occurrence

 

[LittleSister]

'Objects in liquefied sand sink to the level at which the weight of the object is equal to the weight of the displaced soil/water mix and the submerged object floats due to its buoyancy. . .

It is impossible for a human to sink entirely into quicksand due to the higher density of the fluid. . .

IN POPULAR CULTURE
Quicksand is a trope of adventure fiction, particularly in film, where it is typically and unrealistically depicted with a suction effect that causes people or animals that walk into it to sink and risk drowning. This has led to the popular perception that humans can be completely immersed and drown in quicksand; however, this is physically impossible.'

Quicksand - Wikipedia