General Chat

It's possible that the Mary Rose might have survived if heavy lead ballast had been placed inside the vessel along its keel line or (and) if the vessel had been built much wider.

I thought the Mary Rose fell over because of overloading in the artillery sense?

Bobtarian, you are RIGHT!
Handover occurs after successful sea trials. One of Henry VIII laws promulgated after the less than successful sea trial of the Mary Rose when dispute arose as to the bill.

thought snagging was primarily assigned to nylons. stockings, tights, and the like!
(although "a run" might be more appropriate!)

Hmmm "Houston.........we have a snag..........."

doesn't ring as well as the original...

That's explained in the article I've put a link to, Bob.
As is the reality of what the Navy intends to do :-D


...one of my brothers was a proof reader - less is more

Oh yes, I know what snagging is - also used in the building trade.

Hmmm Lignum vitae, to the rescue methinks..(if that is where the leaks are...)

one would think(maybe naively) that the sea trials would be conducted BEFORE the official Handing over?
Bob

I can't remember this happening at Swan Hunter. Shaft alignment and seals were of the utmost importance in all ships and engineers made sure they were fitted perfectly.

,"snagging" is just a shipyard term for faults to fix list.

It is v pleasing that the fault sees to be well within the sort of range that sea trials are meant to discover.

setting up marine propellor shafts on large vessels requires massive precision if leaks and vibration are to be avoided. VLCC containers and roro ferries are more concerned about leaking lubricating oil on account of strict env controls in ports. the bilge pumps can easily deal with any water ingress.

the prop shaft can be fitted with split bearings at extra expense and complexity. The advantage is that revisions and repairs can be carried out in situ no dry dock needed. That makes sense for warships. No doubt some old salts at the Admiralty remembered the fate of the Bismark.

now some guys are going to be busy with the digital successors to dial gauges and feelers working out who got their sums wrong.

After the French carrier "Charles de Gaul" was launched there were a series.of major problems with the prop shafts which make the current QE problems a storm in a teacup.

One of my rellies was a senior commissioning engineer for the Royal Navy.

Seeing as the damn ship cost £3.1 billion.you would have thought the shipbuilders could have got it right 1st time.

No, it is 'snagging', and they hope to be able to fix it without going into dry dock.

http://www.bbc.co.uk/news/uk-42406138

the leak is trivial in the context of the size of the ship and bilge pump capacity. otoh sea trials are designed to detect these problems prior to handover from the builders BAe.

the fault lies with incorrectly installed gland packing no snagging on anything. nowhere near the cost of a misaligned prop shaft but still requires dry dock and a big bill. The crew are said not to like Scotland.

the ship is due in Hampton Roads Q3 2018 to work up the F35 jets so they'll need to get on with fixing the leak or postpone it.

hearts of oak?

It's quite a common occurrence - not just with boats, but any construction - hence 'snagging'.
The bit that leaks was constructed in Govan, but they reckon (hope!) it could be fixed whilst still at sea.

that might have worked ok for Para Handy and the "Vital Spark" or even "Compass Rose" but this time there is going to be serious passing of the buck.
:-0

"Na thats all right guvnor it'll bed in with wear" "I'll just nip the gland up a bit wiv me grips" ;-)

The usual cause of a shaft seal leak is that the engine mountings are not correctly aligned - the tolerances are extremely tight. Any leaks will get worse and if ignored will result in "no engines". These leaks never show up until the vessel is under way.

The problem is widespread from amateur yachts to ...um ... aircraft carriers.
Fixing it for a Volvo engine on my ancient yacht was an engine out job and a fairly significant leak from my bank account.

I would imagine that the HMS Queen Elizabeth will also dent a bank account somewhere far, far away quite badly. That's the trouble with building a ship in section all over the place and expecting ultra tight tolerances to be met. OK in theory but ...

Never mind by the time the leak is fixed the MOD might have saved enough money for some F35 aeroplanes. Or the carrier will have been sold to Brazil / China / France. The Indian scrapyards might consider it as a project.

Or Comrade Jezza will have joined the Russian Federation and the carrier leak will no longer be our problem.

Our brand new aircraft carrier has sprung a leak :-( :-(