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Old 31 October 2001, 12:34   #1
Country: UK - Scotland
Town: Highlands
Boat name: Quicksilver
Make: Quicksilver
Length: 3m +
Engine: Mariner 15hp
Join Date: Aug 2001
Posts: 1,771
Needles Lighthouse - UK's Leaning Tower of Pisa


This will only mean someyhing to other BIBOA members. In Winter Riblines there are two pictures of Hot Lemon III powering past The Needles Lighthouse, see pages 4 and 16. Is there something wrong with the lighthouse? In the first picture it is leaning sharply to the left, in the second it is leaning sharply to the right!

Is this a usual phenomenum. Perhaps the owners of Hot Lemon III can explain all?

Keith Hart

Small boat - BIG truck
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Old 02 November 2001, 12:42   #2
Country: UK - Isle of Man
Town: Peel
Boat name: Jane L
Make: Scorpion
Length: 8m +
Engine: 315 Yanmar
MMSI: 235077935
Join Date: May 2000
Posts: 200

Although I am not connected with Hot Lemon, I did
take the pic you refer to on page 16 of Fiblines, and can explain ....

You will notice that the lighthouse bends in the direction of travel in each picture. This happens to all inanimate objects when they are struck by the air pressure wave generated by a high speed Rib such as Hot Lemon which, as we all know, travels at a terrific rate of knots.

The effect that this shockwave has lasts only for a tiny fraction of a second and, although is sometimes captured on film, is rarely visible to the naked eye. For this reason you may not have witnessed such an event.

I understand that the Thrust SSC land speed record holders generated similar air pressure waves when approaching the speed of sound.

To better illustrate the effect I have attached (I hope) another picture taken on the same day. This (I think) is a Fabio Buzzi job and was impressively quick without being too large. I couldn't help noticing a number of well known Rib owners drooling over it, and some were even lucky enough to go for a quick spin.

I would guess that it was travelling half as fast again as Hot Lemon, and you can see what happened to the lighthouse as a result.

Does this answer your question ?
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Old 02 November 2001, 14:14   #3
Country: UK - England
Town: Iver, Bucks, UK
Boat name: Prime Rib II
Make: Humber Ocean Pro
Length: 6m +
Engine: Mercruiser 1.7 diese
MMSI: 235086032
Join Date: Jul 2001
Posts: 443
Well this really is a lot of rot. This has nothing to do with air pressure. As anyone with a modicum of knowledge would know this relates more to Einsteinís Special Theory of Relativity, which as you may know came before his General Theory of Relativity and is the key to understanding the phenomenon exhibited in the picture above. As you may be aware, as the speed of motion increases, (relative to a fixed point) a degree of either stretching or compressing occurs. Obviously this change of apparent size is too small to be observed in the normal course of events. However, when the speed of a given object approaches the speed of light, then any static object, as observed by the observer, (or in some cases The Sunday Times), will appear to shrink. This would normally go unnoticed for two reasons.

1), The amount of shrinkage is normally too small to see, due to the small relative speed difference of the two observing points, (not so in this case since the whole point of this is a rather fast 'Hot Lemoní), and
2), The 'shrinkage' is normally uniform, thus no leaning would be apparent. The strange 'bend' in the lighthouse therefore is obvious and all due to the angle of the camera, since it is not capturing a vital clue to this anomaly!

It is correct that the bending only happens for a fraction of a second, however, as you will observe in the photograph, there would appear to be no sign of any building work being done to the structure. This is crucial in the understanding of the phenomenon. There was in fact a good deal of scaffolding and wooden boarding around the bottom of the lighthouse at the time, which was not in view. Since this will stop any form of 'Einstein contracting/stretching', the lighthouse did not move at the bottom. However, since there was no scaffolding or boarding at the top, this did allow the structure to contract, (due to the speed of Hot Lemon), momentarily at the top. Thus a 'lean' was observed. This phenomenon is known as 'Planckís Constant'. If anyone would like any more information about this, I will be at the BIBOA AGM in a week or so and would be glad to oblige....... if they buy me a pint.
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Old 02 November 2001, 14:32   #4
Country: Other
Make: FB 55
Length: 10m +
Join Date: May 2001
Posts: 1,711

Sheeesh, you guys smoking some good sh*t, or what?!
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Old 05 November 2001, 00:43   #5
Country: Greece
Boat name: SUN KISS II
Make: Nuova Bat 9 Falcon -
Length: 5m +
Engine: Outboard Mercury 115
Join Date: Jun 2001
Posts: 639
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To all participants,

I am trying to understand what exactly are you talking about !!!
To clear up some things. If we had a photo of that rock, like the above, without trying to catch the speeding rib, what would we notice ? The light house is acually vertical, or is something missing from the posted picture ?????
Michael a.k.a "Bat Falcon"

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