The Holyhead Hum..?

[Tecsyn]

Do you have the departure and arrival times, so I can try to eliminate this or otherwise..? Is the Nordica the same as the HSS?

[Porty]

Do you have the departure and arrival times, so I can try to eliminate this or otherwise..? Is the Nordica the same as the HSS?

Yes she's in around 6.30am and 19.30pm.

[KnightRider]

Arrives approx anywhere between 05:50 and 06:30 most morning's apart from Sunday.Every night at 19:30, but most of the time she can be heard before she is seen. one person I know who lives in Porth Y Felin says that the vibrations/hum make the pictures on their wall move slightly.

[DCI Gene Hunt]

Sounds like i need to investigate this strange hum!

[Tecsyn]

Do you have the departure and arrival times, so I can try to eliminate this or otherwise..? Is the Nordica the same as the HSS?

Yes she's in around 6.30am and 19.30pm.

Ok that's not the cause then as I hear it through the night

[KnightRider]

hummmmm i wonder what it is? (boom boom tish)

[ben 10]

the description I gave? no-one's got it. It's the breaky. Problem solved

[Tecsyn]

the description I gave? no-one's got it. It's the breaky. Problem solved

How's that work..?

[ben 10]

Imagine a tunnel, very long, empty and hollow. Blow some wind down the tunnel through a few small holes and listen. Amplify it and there's your hum.

wind tunnel tec. The air within the hollow structure constantly shifting and travelling the length of the breaky. Sometimes at high speed with nowhere to go but into and with the walls.

[gazza]

I saw another theory out there that suggested storm waves battering the sea floor is causing the earth's crust to emit these vibrations...

http://physicsworld.com/cws/article/news/39815

[Tecsyn]

Imagine a tunnel, very long, empty and hollow. Blow some wind down the tunnel through a few small holes and listen. Amplify it and there's your hum.

wind tunnel tec. The air within the hollow structure constantly shifting and travelling the length of the breaky. Sometimes at high speed with nowhere to go but into and with the walls.

The breaky is not hollow...

[Nooks]

No, I didn't think so either. It's just loads of lumps of the mountain piled in innit?

[welshgalq8]

Imagine a tunnel, very long, empty and hollow. Blow some wind down the tunnel through a few small holes and listen. Amplify it and there's your hum.

wind tunnel tec. The air within the hollow structure constantly shifting and travelling the length of the breaky. Sometimes at high speed with nowhere to go but into and with the walls.

The breaky is not hollow...

Could it be the noise of the waves being deflected from it? Do you notice it when the weather is bad?

[ben 10]

it is hollow. I've seen pics of it's construction and there are massive massive trunks of wood that were used to build the framework and all the outside was constructed around them. The mountain was quarried for the stone to be built around the frame. I know it's 30ft thick in parts but it doesn't matter what size or thickness the walls are the interior is hollow and makes the holyhead hum.

[Nooks]

You can still see parts of the framework on places. As far as I know the framework held the train tracks. As you say the walls were built on each side but then I assumed the space between was filled in to give it strength.

Anyway, if it is hollow where does the sound eminate from?

[Nooks]

Just had another thought: If it is hollow then it would be akin to a giant organ pipe. The largest known organ pipe in the world is the 128ft bass tuba in Liverpool cathedral. it resonates at a frequency of just 4hz. You can't hear it (but baby, you feel it) so I'm just wondering what frequency the breakwater would resonate at? I could calculate it but time doesn't allow just now but it's got to be very very low. It wouldn't be a hum, more like a recurring draught.

[TreFFS]

I very much doubt that the Breakwater is hollow. To build such a structure would have involved a lot of unnecessary labour. The most there would be are occasional shelter rooms.

The wooden piles referred to by ben would have been in place simply to support the rails for the trains carrying the foundation rubble. The limestone outer "facing" did not come from the Mountain which is made of schists (sorry!) and quartzite stone/rock.

This is from an interesting article on the building of the Breakwater:

Rubble from the quarry was used to form the foundation, and it is more than 500 feet wide all along its length, and in some parts very deep. The actual rubble came from the Mountain, while the gigantic blocks of wall were brought from Moelfre by sailing boat. Laying the foundations were of course the most difficult and dangerous parts of the work, which was frequently, hindered by storms, and despite the care Mr. Jackson talks about 20 workmen lost their lives between 1849-1852.

It is noted that the pay of a stone-mason was ?/6 per day, and that of a labourer 2/6. The sanount of stone they moved was tremendous - 24,000 tons - laid in one week. Approximately 7,000,000 tons of stone was laid.

 A solid wall of stone was laid on top of the foundation, some 39ft high, of two decks, with a rail track laid on the lower, and a parapet on the seaward side. The swell of the sea was reduced considerably as soon as the stones reached sea level, and ships began to shelter more and more within the harbour, thus thoroughly justifying the building of the harbour even before its completion


http://www.holyheadbreakwater.com/BwBuild/index.htm

[taclar]

Could it be anything to do with the caves around Holyhead?  It would be possible if we're talking about hollow structures.  Fortean Times has done pieces on these strange 'hums' around the world, think they call it 'humadruzz'.  There's many theories been thrown into the pot as to what's caused it.   

[Tecsyn]

It's probably some industrial unit's blydi air-con! In the 70's the breakie was smashed through by a big storm - I saw it then, and there was no hollow bit... The sound is best described as though an artic lorry was parked, say 50 metres from my house with the fridge unit running...

[Shell]

Lidle have some kind of refrigerator fans of some size located on the back of the building.  These are noisy.  I'm sure Tesco and Iceland have the same.  Could it be these making the hum?

[Porty]

Will we ever know ?

[Nooks]

It's probably some industrial unit's blydi air-con! In the 70's the breakie was smashed through by a big storm - I saw it then, and there was no hollow bit... The sound is best described as though an artic lorry was parked, say 50 metres from my house with the fridge unit running...

...which brings me back to my earlier deduction - the Leisure Centre. Very noticable from Valley of the Rocks and I would estmate similar where you live Tecs. If I hear it over the weekend I'll record it on my phone and upload it into the tunes section!

[ben 10]

Will we ever know ?

I've herad it the staff sleeping down the port at night that make the hum.(sorry serious thread) (( not that serious really though isit?))

[Tecsyn]

Will we ever know ?

I've herad it the staff sleeping down the port at night that make the hum.(sorry serious thread) (( not that serious really though isit?))

Well, it keeps me awake at night Ben, and then I get angry, and people don't like me angry...

Shell, I suspect you are right. My next problem is how to isolate those potential causes and see if it stops... No doubt the sad people still monitoring what I say here will come and arrest me if any of those places burns down in the near future...