callamity at Maryport marina

[pheonix]

yesterday at hw there was a gate failure at maryport marina the ensuing tidal wave wiped out a nmber of finger pontoons causing the sinking destruction and damage to several craft.luckily my boat suffered only cosmetic damage

 

[Searush]

Ouch, what a mess. Did the gate simply burst then? I always thought such gates were closed on the ebb to keep a certain depth so that boats float. Are you suggesting that the gates normally close on the flood?

 

[jonjo]

Ouch but I am confused.

Why did a multihull suffer so much, I would have thought fin keelers would come off worse given abnormal water levels.

 

[Searush]

http://www.timesandstar.co.uk/freak_wave_causes_massive_damage_at_west_cumbrian_marina_1_619690?referrerPath=2.1943/2.2850

It seems that the gates fell down causing the 6' tidal wave? Something tells me that the journos know nothing about marinas, water or tides. More pics on the above link, but not a pretty sight.

 

[Thistle]

Ouch, what a mess. Did the gate simply burst then? I always thought such gates were closed on the ebb to keep a certain depth so that boats float. Are you suggesting that the gates normally close on the flood?

I wonder if the lock didn't open at the correct time and was suddenly forced open as the tide level rose outside.

 

[pheonix]

gates left closed at hw

Ouch but I am confused.

Why did a multihull suffer so much, I would have thought fin keelers would come off worse given abnormal water levels.

as said the gates were left closed during adverse weather at HW CATCH GAVE WAY AND GATE DROPPED OPEN the gate during normal opps is closed at LW water inside holding gate shut at this point there was a rush of water causing a huge wave that ripped through the first few pontoons lifting the pontoons and craft and presumably giloutining the stern of the cat the pontoon with the cat then broke away from its pilings cascading into the next row of craft sinking some boats and destroying others

 

[Searush]

Uhh- oh. So the marina staff tried to use a gate designed to hold water in (where pressure holds it against the frame) to actually try to keep water out - in strong wind & wave conditions. This would mean that only the securing catch would be holding it - and that ain't designed to to hold that force. Sounds like criminal negligence to me. This is going to cause a BIG stink. Who owns the marina?

 

[Lakesailor]

I was at Workington yesterday and it was fair breezy. 50mph winds. I wonder if that was part of the problem?

 

[Rooster]

When I kept my boat there, I don't think many of the marina management knew much about marinas, water or tides, never mind the journos!!
Do hope everybody safe and this mess can be resolved quickly and peeps back out sailing in the near future.

R

 

[jonjo]

Uhh- oh. So the marina staff tried to use a gate designed to hold water in (where pressure holds it against the frame)

Right, got it now, thanks.

@pheonix - The full stop key is bottom right.

 

[earlybird]

Uhh- oh. So the marina staff tried to use a gate designed to hold water in (where pressure holds it against the frame) to actually try to keep water out - in strong wind & wave conditions. This would mean that only the securing catch would be holding it - and that ain't designed to to hold that force. Sounds like criminal negligence to me. This is going to cause a BIG stink. Who owns the marina?

For as long as I've known Maryport Marina, which is some 12 years, the gate has been kept shut in severe conditions in order to protect the boats within. Clearly, something went badly wrong yesterday, but the staff would only have been following what, to them, was normal practice. Note that the gate had very recently been re-furbished, and this occasion was probably it's first test.

 

[Searush]

Lock gates are always designed so that the water pressure behind them holds them more firmly closed - ie failsafe. Using them in the "reverse" direction where water pressure is forcing them open against a simple latch is simply dangerous.

Were the refurbishers warned of this misuse of the gates? Was the misuse of the gates "agreed practice" - and who agreed it? I trust the H&S people are investigating this - lives could easily have been lost on a BH weekend.

Afterthought;
If the gates are required to be used as a wave breaker, then there should be a sluice panel that allows the pressure & water level to remain equal on both sides. This could be closed if the level outside goes below the required level inside, or it could simply be high enough in the gate to be above the required level. Seemples

 

[jason -and the arguenauts]

The lock gates in Cardiff bay are occasionally used to keep very high storm tides out and prevent flooding. As far as I can see there are no locks / catches on them.

 

[earlybird]

According to today's news reports, Maryport Marina claim that the gates are designed for these conditions, and have been operated in that manner for 20 years. The recent refurbishment did involve new locking mechanisms, designed by consultants, who have been on site to-day. An inquiry is under way.
I had a look this-morning. The gate locking is done by hydraulically operated bolts, engaging the top of the gate. The anchor bolts which attached these hydraulic mechanisms to the lock walls have broken out of the concrete.
I could only see from some distance away, but the anchor bolt arrangement appeared less substantial than I would have expected, given the overall size of the gate and the battering it gets, but no doubt the enquiry will decide in due course.
In the marina, clearing up was in progress, but it still looks as if a large bomb has exploded in the N. part of the basin.

 

[Searush]

Concrete has very poor resistance to shear stress does it not? That is why you drive wedges under a slab before whacking it with a hammer when you need to break it up. Perhaps it was poor design after all then.

I still think that level equalising sluices would have significanlty reduced the stress it was under when "reverse loaded".

 

[earlybird]

[QUOTE

I still think that level equalising sluices would have significanlty reduced the stress it was under when "reverse loaded".[/QUOTE]

I agree that would seem an improvement. Perhaps the gate could be modified. It must be many months before Maryport is back to anywhere near normal. Meanwhile, I think there might just be an exodus of boats, those still afloat anyway, to Whitehaven Marina, just down the road. That has a lock as well, but it's got 2 sets of gates.

 

[Elessar]

The lock gates in Cardiff bay are occasionally used to keep very high storm tides out and prevent flooding. As far as I can see there are no locks / catches on them.

very different. That design of gate isn't held closed by the water because of the way they rotate around a pivot, a hydraulic ram keeps them shut (and open) the worst that could happen is that the seal is prized open to let water seep in. To fail totally they would have to completely exceed they design strength and fall to bits, and they are designed to keep best part of a 15m tide in so an extra meter or so in the "wrong" direction in extreme weather is childs play for them!

 

[Searush]

(snip) . . . to Whitehaven Marina, just down the road. That has a lock as well, but it's got 2 sets of gates.

They are also likely to be designed for holding water in & will probably both close firmer at low water. However, they WILL have sluices to fill/empty the lock, which means that the lock can be filled to support the outer gates against bad weather & high tides. The inner gate will be at risk, but not likely to be subjected to additional wave action.

I must have a peep on Google earth!

 

[jimi]

Lets hope Noah was'nt moored there .. or that'll be another 2 year saga!

 

[Searush]

Whitehaven seems to have swing gates, which appear to be designed to take pressure from outsid of the lock. Looks far less likely to fail to me. It is also within a reasonably well sheltered outer harbour. Some lessons for Maryport?