Archaeologists dig up rare medieval waterwheel

[Adsos Letter]

Source: East London Advertiser
Mike Brooke

ARCHAEOLOGISTS have uncovered a rare medieval tidal mill on the River Thames.

The discovery was made at Limehouse Reach in East London, where a team has been excavating peat soil on the foreshore at Greenwich Wharf, opposite the area known as Millwall on the Isle of Dogs.

It is remarkably well preserved in riverside peat deposits, archaeological experts from the Museum of London revealed today.

They believe it is the foundations of London’s earliest-found medieval tide-powered mill.

The huge structure, measuring 30ft by 36ft at its base, would have had a wheel diameter of 16ft, an incredible size for a wooden structure of this type which represents an extraordinary example of medieval engineering, dated to the 12th century. Analysis of tree rings has dated the trees used for its construction to 1194.

http://www.eastlondonadvertiser.co.uk/content/towerhamlets/advertiser/news/story.aspx?brand=ELAOnline&category=news&tBrand=northlondon24&tCategory=newsela&itemid=WeED16%20Feb%202009%2020%3A43%3A49%3A903

[petronius]

1. That paper has the best headline ever: "Lanuage is no barrier"

for an article about a play in Japanese. :rofl:

Still haven't found the water wheel yet - your link got a bit truncated...

[Adsos Letter]

2. Sorry about the link...it should work now...

the headline bit is funny! :D

[petronius]

3. Yep, it works

That's a really cool find (although the article would be improved by pictures or a sketch). Tidal power seems like a much more complex and less obvious engineering problem than a mill on a stream...

[Adsos Letter]

4. One of my ongoing gripes...

is the lack of accompanying photos or drawings in these stories.

I was just reading something the other day (in passing on a broader topic of English history) about the vulnerability of stream and river powered mills to drought conditions...I had never thought of that aspect before.

[petronius]

12. I can see how that would be a concern. I'd guess that the larger the river

the more reliable the flow would be.

On the other hand, tidal mills would be dealing with a narrower range of water levels (with a stream you can channel in water from as far upstream as you need to produce the proper head) and would be vulnerable to storm surge.

[Dover]

5. Interesting...thanks! And here's a link explaining what the "Domesday Book" was all about.

http://en.wikipedia.org/wiki/Domesday_Book

Domesday Archives Available Online
http://www.domesdaybook.co.uk/

Would love to see a picture of the wheel when they assemble it. So it was run by the tides?
Sounds very sustainable to me. Here's a picture of a tidal mill I found online that might be
similar to the one found (and a link to a Wikipedia article on that subject):



http://en.wikipedia.org/wiki/Tide_mill

[Hardrada]

6. Check with Senator McCain!

[Morning Dew]

7. You bring some wonderful info.

I don't read all of them but they're appreciated.

[Adsos Letter]

9. It is my pleasure Morning Dew...

some stories are more interesting than others, of course...but it's a big world out there, in both Time and Space. :hi:

Thankyou for the kind words. :hug:

[aquart]

11. Very appreciated.

I LOOK for them.

[Dover]

14. dupe..n/t

[EFerrari]

8. Hey -- did you see my post for you about The Invention of Air

about Joseph Priestly, Adams, Franklin? It seemed to have all the stuff you're reading about right now. I caught a BookTV segment and thought of your reading list. lol

http://search.barnesandnoble.com/booksearch/isbnInquiry.asp?r=1&ISBN=9781594488528&ourl=The-Invention-of-Air%2FSteven-Johnson

[Adsos Letter]

10. No, I didn't! Do you have a link, or shall I search?

Right now I am reading arguments over the historiography regarding the causes of the English Civil War.

It seems there was a lot of political/religious machinations, with attendent shouting, pouting, and bitter recriminations...and sporadic periods of violence and accompanying bloodshed, and banning...sort of like DU during the primaries. :D

[EFerrari]

13. I stuck a link up in there. If you liked the primaries

you might enjoy this. It was a letter between Franklin and Priestly that sparked the famous correspondence between Franklin and Adams. Priestly did all kinds of stuff like help found the Unitarians and figure out that this big invisible nothing was air. He sort of made science American.

[Adsos Letter]

15. Thanks for the link; I'll bookmark for later, as I will shortly be going in ...

to place my ice-cold feet against my wife's nice warm legs...might be a topic of conversation, if I survive the experience... :D

[Dover]

16. The modern version

Lunar power could play a significant part in the UK's energy mix. The Moon's gravitational pull on our oceans means the British Isles are surrounded by strong tidal flows and engineers are aiming to tap them with undersea turbines. But maintaining underwater tidal mills could be difficult.

One group thinks it has the answer. Swanturbines has deliberately simplified its design to minimise the risk of problems. The Swansea-based team recognises that the harsh sub-sea environment can take its toll on moving parts and control sub-systems so it has eliminated those elements more likely to require regular maintenance or repair. The result, it claims, is a cheaper and more versatile solution than its rivals'.

'We've gone for a direct drive, low-speed permanent magnet generator,' said Swanturbines' co-founder Dr Ian Masters. 'It gives a single moving part, which is an advantage. We looked at all the things that one could have, such as pitch control, pitch motors, the whole drive train. We said to ourselves, "Let's leave all those things out and do something else to reduce the risks."'

The team has spent five years developing its answer. The key is fault-tolerant electronics which generate DC. The electric current is fed to units on dry land, which are easily accessible by maintenance and repair crews, and where it can be converted to more useful flows.

The one remaining moving part, the rotor itself, can be maintained by raising it to the surface. A patent granted to the Swanturbines designers reveals that the pylon on which the rotor sits could be telescopic and raised above the waves simply by pneumatic or other means.

One of the Welsh turbine designs could generate 350kW when fitted with a rotor up to 15m in diameter. 'Tidal turbines are much slower moving than wind turbines but the sea is 800 times denser than the air,' said Masters. 'Ours will turn at about 12rpm.'

A one metre diameter prototype has been towed by Swansea University's research vessel for tests at a range of flow speeds and rotational speeds. Swanturbines is now seeking investment for the first full scale demonstrator, planned to be installed off the Swansea shore. 'It will be in the order of a small number of millions of pounds,' said Masters...cont'd

http://www.theengineer.co.uk/Articles/Article.aspx?liArticleID=296542

[Adsos Letter]

17. Great article!

Necessity combined with a profit...the Mother of invention.