Jump to content

Disasters at Sea


blackrose

Featured Posts

I really enjoy watching this programme and also Aircrash Investigation. Not sure why? Maybe from morbid curiosity but I think it's more to do with the way the investigators systematically uncover the causes of the disasters, which often include a series or chain of events.

 

Anyway, I'm just watching one where a 166m vessel capsized as a result of going into shallow water and hitting rocks and it just made me think about how strong steel canal boats are - at least in terms of plate thickness. I don't think I could puncture the 6mm plate on the sides of my 29 tonne widebeam even if I deliberately ran against rocks at full speed. 

 

For example, at 114,000 tonnes, how thick would the plate on a vessel like the Concordia need to be to have bounced off those rocks rather than being sliced open? That's a rhetorical question, you don't need to do the calculation, but I dare say a few feet thick and completely impractical. I know some commercial hulls are double skinned instead.

Link to comment
Share on other sites

2 minutes ago, blackrose said:

I really enjoy watching this programme and also Aircrash Investigation. Not sure why? Maybe from morbid curiosity but I think it's more to do with the way the investigators systematically uncover the causes of the disasters, which often include a series or chain of events.

 

Anyway, I'm just watching one where a 166m vessel capsized as a result of going into shallow water and hitting rocks and it just made me think about how strong steel canal boats are - at least in terms of plate thickness. I don't think I could puncture the 6mm plate on the sides of my 29 tonne widebeam even if I deliberately ran against rocks at full speed. 

 

For example, at 114,000 tonnes, how thick would the plate on a vessel like the Concordia need to be to have bounced off those rocks rather than being sliced open? That's a rhetorical question, you don't need to do the calculation, but I dare say a few feet thick and completely impractical. I know some commercial hulls are double skinned instead.

 

I think the idea is to have a crew and skipper that knows what they are doing. Unlike the Concordia. Thats the mitigation against having a relatively thin hull.

 

The momentum involved would likely split anything up to more than a few feet thick.

 

But I dont claim to be a physicist.

Link to comment
Share on other sites

4 minutes ago, The Happy Nomad said:

 

I think the idea is to have a crew and skipper that knows what they are doing. Unlike the Concordia. Thats the mitigation against having a relatively thin hull.

 

Yes in that particular case it wasn't a series of events that caused the disaster. It was having one idiot in command.

Link to comment
Share on other sites

15 minutes ago, blackrose said:

Anyway, I'm just watching one where a 166m vessel capsized as a result of going into shallow water and hitting rocks

 

 

Because the navigation (hydrographic) authorities had not issued a 'notice to mariners' informing them of a new shoal that had developed following dredging.

 

No one told the pilots.

Link to comment
Share on other sites

It is said that scale wise our modern narrow boats have thicker steel hulls than WW1 Dreadnoughts and I bet that scale wise they move through far shallower waters. That is with the lower section of the hull moving through the bottom of the water

Edited by Tony Brooks
Link to comment
Share on other sites

Steel narrowboats are massively over engineered, can't think of one that has sunk or had really bad structural  damage unless it was already in poor condition

Link to comment
Share on other sites

I really like Mentour Pilot on YouTube. He gets right down to the details of some really grim aircraft accidents. 

 

As long as you can ignore the sponsorship and occasional adverts the content is very good. 

 

Example. The Keg'erth air disaster. 

 

 

Edited by magnetman
  • Greenie 1
Link to comment
Share on other sites

7 minutes ago, magnetman said:

I really like Mentour Pilot on YouTube. He gets right down to the details. 

 

As long as you can ignore the sponsorship and occasional adverts the content is very good. 

Yes, I have been watching lots of his videos in recent weeks - you can just skip through the sponsorship bits.  There are a number of thought provoking messages that are relevant to the more challenging boating activities, for example

  • one pilot flies the plane, while the other fixes the problem
  • the way the crew work together (crew resource management) checking each other, offering ideas and suggestions, to avoid groupthink. Very much countering the "the captain is God" myth. 

 

PS I enjoyed this one - how to land a passenger jet if all the pilots are incapacitated. It rather looks as though getting onto the correct radio frequency is the hardest bit ...  

 

Edited by Scholar Gypsy
Link to comment
Share on other sites

For those interested in intrepid small boat, boating into an extremly hostile environment.

The story of the loss of the Berserk, a 14m steel sloop,  and her crew aboard in February 2011 after an storm forced them to leave an anchorage close to McMurdo Sound in Antarctica where they were awaiting the return of high speed mechanized dash to the South Pole. Coincidently in the same anchorage was HMNZS Wellington which was later dispatched in a multinational and disparit search effort. 

 

https://interactives.stuff.co.nz/2022/01/the-berserk-incident/

 

Very little was made of the incident of the time as this part of the world as the event was totally swallowed by the enormity of the Christchurch earthquake at the time.

This event was actually held by the captain, from the crew of HMNZS Wellington, as they were severly threatened by the enormous seas and topsides icing undertaking the search.

  • Greenie 2
Link to comment
Share on other sites

59 minutes ago, Captain Pegg said:

While the plate thicknesses of a narrowboat will be proportionally thicker than a sea going ship it is also the case that the steel in a narrowboat is most stressed when being lifted or sat on stocks.

 

That's the case for any vessel, not just narrowboats surely? The least stress on any hull will be while it's being supported by water. I think it's the same principal for aircraft wings as long as they're not doing aerobatics. They're more stressed on the ground than being supported by fast flowing air.

Edited by blackrose
Link to comment
Share on other sites

19 minutes ago, magnetman said:

It would be interesting to see what sort of crane would be used to lift a sea going ship. 

 

Dry dock v crane/travel hoist is quite an interesting topic.

 

 

Travel hoists that lift up to 1500 tonnes are now in service.

https://downeastboatforum.com/threads/the-world’s-largest-travel-lift.35376/

Edited by DandV
  • Greenie 1
Link to comment
Share on other sites

There’s been another big human error causing a ship disaster. A bulk carrier ran on the rocks off Mauritius broke up and spilt tons of oil on a protected area. The reason was because they wanted to get a mobile phone signal!

The main stress in ships is the hogging and sagging in the swell and they are designed to withstand it but still things happen. Ships still break the most resent being a Japanese container ship which sort of bent up and down in the swell before breaking in half. Narrow boats are unlikely to come across these forces.

  • Greenie 1
Link to comment
Share on other sites

2 hours ago, magnetman said:

Quite a good argument for single handed boating. 

 

I rather think this vindicates my approach of having a crew, but ensuring that it is comprised entirely of imaginary characters.

 

That said, my imaginary shipmate Wilson has started to act a little oddly since we left the T+M.

To be fair to the lad, I'm not sure how much one can reasonably expect from a football with a face painted on it in crayon.

 

  • Greenie 2
  • Happy 1
Link to comment
Share on other sites

I've always found that whenever anyone attempts to assist me things go wrong incredibly quickly because my way of doing it was technically correct and manageable without assistance.  

 

If you get it right in the first instance the only outcome of someone else getting involved is that it will go wrong.

 

Obviously in larger systems there is a need for more operational units so it could become complex. 

 

This is where automation will be a real boon in future. So much conflict can be avoided it will be a wonderful world. 

 

 

Link to comment
Share on other sites

3 hours ago, Scholar Gypsy said:

Yes, I have been watching lots of his videos in recent weeks - you can just skip through the sponsorship bits.  There are a number of thought provoking messages that are relevant to the more challenging boating activities, for example

  • one pilot flies the plane, while the other fixes the problem
  • the way the crew work together (crew resource management) checking each other, offering ideas and suggestions, to avoid groupthink. Very much countering the "the captain is God" myth. 

 

PS I enjoyed this one - how to land a passenger jet if all the pilots are incapacitated. It rather looks as though getting onto the correct radio frequency is the hardest bit ...  

 

I can land and take off a Boeing 737

100_8224.JPG

  • Greenie 1
Link to comment
Share on other sites

2 hours ago, blackrose said:

 

That's the case for any vessel, not just narrowboats surely? The least stress on any hull will be while it's being supported by water. I think it's the same principal for aircraft wings as long as they're not doing aerobatics. They're more stressed on the ground than being supported by fast flowing air.

 

I doubt it is because firstly ships are perhaps not lifted and docked in quite such a brutal way as narrowboats and also that they experience very different forces in service due to wave action than a narrowboat ever would, such that I think it's probable the highest stresses ever experienced by a sea going ship happen at sea and not in the dock. Hence the comparison may not be properly like for like.

 

BTW the Costa Concordia didn't weigh 114,000 tonnes. 114,000 (unitless) was it's gross tonnage and it's displacement would have been much less, although the largest ships ever built exceed 600,000 tonnes displacement fully loaded.

 

ETA - I'd also be very surprised if aircraft wings are more stressed under their own weight than they are by the dynamic forces of uplift and the effects of turbulence and changes in air density when flying.

 

Edited by Captain Pegg
Link to comment
Share on other sites

1 hour ago, Captain Pegg said:

ETA - I'd also be very surprised if aircraft wings are more stressed under their own weight than they are by the dynamic forces of uplift and the effects of turbulence and changes in air density when flying.

I imagine that fatigue loading under varying stress is far more critical than the static stress either on the ground or when flying in steady state conditions.

Link to comment
Share on other sites

7 hours ago, David Mack said:

I imagine that fatigue loading under varying stress is far more critical than the static stress either on the ground or when flying in steady state conditions.


The forces associated with activation of the control surfaces on the wings must be significant too.

Link to comment
Share on other sites

11 hours ago, Dav and Pen said:

The main stress in ships is the hogging and sagging in the swell and they are designed to withstand it but still things happen. Ships still break the most resent being a Japanese container ship which sort of bent up and down in the swell before breaking in half. Narrow boats are unlikely to come across these forces.

 

Depends on how much tidal work they do.

Link to comment
Share on other sites

10 hours ago, Captain Pegg said:

 

I doubt it is because firstly ships are perhaps not lifted and docked in quite such a brutal way as narrowboats and also that they experience very different forces in service due to wave action than a narrowboat ever would, such that I think it's probable the highest stresses ever experienced by a sea going ship happen at sea and not in the dock. Hence the comparison may not be properly like for like.

 

Yes the comparison may not be like for like. Similarly your scenarios may not be comparable either. Narrowboats aren't always lifted in a brutal way. Often they float into dry docks and are gently lowered. Some canal boats do encounter waves. I don't know how the <1m waves my boat has been though on the tidal Thames compare in terms of scale to an oil tanker at sea but I suppose any comparison could only ever be done on a case by case basis.

Edited by blackrose
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.