john_morris_uk
Well-Known Member
Hmm. That’s a thought. My harness is clipped onto it.
I’m on the ferry again tomorrow. Let’s see what happens when I go through security from the French side.
Taking your Lifejacket on a ferry
- Thread starter john_morris_uk
- Start date
I’m on the ferry again tomorrow. Let’s see what happens when I go through security from the French side.
john_morris_uk
Well-Known Member
Got in my return ferry this morning. I got to the bag scanning queue and got waved through without my bag being scanned. Hey ho…
rogerthebodger
Well-Known Member
I cannot understand why a CO2 life jacket would be dangerous on a ferry. On an airplane yes. I took my dive buoyancy aid in the cabin for a flight to Perth then on to Melbourn and Great Barrier reef with no issues
Cerebus
N/A
The whole thing sounds strange.
The ferry operators would provide some obscure reason or excuse I think.
I took a pocket sized digital barometer on a flight across the Atlantic and it showed just how low the pressure in the cabin was; lower than anything I have ever seen ever whilst on land or at sea. I was amazed to see such a low pressure.
ashtead
Well-Known Member
If you are travelling on Wightlink while sinking isn’t a common occurrence they have a whole raft of other excuses latest today is broken down vehicle on loading ramp (no tow trucks?)!
Cerebus
N/A
I would have expected a tractor or 4x4 to be nearby at least.
Not exactly proper planning.
colind3782
Well-Known Member
On a normal airliner the cabin pressure is equivalent to being at an altitude of 8,000'. A couple of the later models (A380?) are pressurised to a lower altitude, 5,000' I think and some of the smaller corporate jets to 2,000' or thereabouts.
john_morris_uk
Well-Known Member
Is that economics or some other reason?
colind3782
Well-Known Member
It's to do with the structure of the fuselage as the inside pressure has to be balanced with the outside pressure so as not to stress it too much.
wonkywinch
Well-Known Member
Economics, ie cost and weight of building structure strong enough for multiple pressurisation cycles.
Cabin altitude ideally would be sea level for passenger comfort so the 5,000 to 8,000 feet is a trade off. 10,000 feet is the maximum altitude, above that, we need oxygen, especially older or infirm people.
Several Comet accidents were related to metal fatigue caused by pressurisation cycles.
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john_morris_uk
Well-Known Member
I don’t quite follow that. At 30,000 feet plus there will be a pressure difference. Also the clue is in the name ‘pressurised’. I was wondering why they choose the equivalent height that they do.
john_morris_uk
Well-Known Member
That makes perfect sense. Thank you.
penberth3
Well-Known Member
Structural strength (and weight) depends on the pressure difference. Lower cabin pressure - lighter aircraft - cheaper.
Sea Change
Well-Known Member
I had a yacht delivered by road to Mallaig, and went across on the ferry from Skye as a foot passenger. I did get a few funny looks going up the gangplank, wearing a lifejacket and carrying a rolled up dinghy on my shoulder...
mjcoon
Well-Known Member
You'd think they would just tell you to jolly well wear the oxygen masks... Ryanair?
justanothersailboat
Well-Known Member
Ryanair? Oxygen's extra!
Objecting to lifejackets on a (ferry) boat seems crazy and awful to me and is clearly a bit of a problem in some sailing one-way trip scenarios. But I wonder if there is a sort-of-not-crazy-if-you-squint-hard-enough reason: maybe they're worried about nervous, panicky passengers doing something unexpected, maybe during a real emergency, and finding some way to make it worse. An unlikely event, but I imagine it features more prominently in their safety planning than one-way trips by yacht crew.
(In the same way as I bet airlines won't be thrilled if a nervous flier has a parachute in a cabin bag... then again, they might think you're a D B Cooper wannabe. That could be worse)
Objecting to lifejackets on a (ferry) boat seems crazy and awful to me and is clearly a bit of a problem in some sailing one-way trip scenarios. But I wonder if there is a sort-of-not-crazy-if-you-squint-hard-enough reason: maybe they're worried about nervous, panicky passengers doing something unexpected, maybe during a real emergency, and finding some way to make it worse. An unlikely event, but I imagine it features more prominently in their safety planning than one-way trips by yacht crew.
(In the same way as I bet airlines won't be thrilled if a nervous flier has a parachute in a cabin bag... then again, they might think you're a D B Cooper wannabe. That could be worse)
penberth3
Well-Known Member
I guess the passengers would pay for their own oxygen, at so much per Therm?
wonkywinch
Well-Known Member
At cruising altitude, the cabin altitude in a B787 is around 6,000 feet, 840mb or 12psi.
The doors are each about 2.5 sq m (26 sq ft or 3875 sq in). There is approx 46,000 lbs of air pressing on that (plug) door, ie almost 21 tonnes.
Despite what the popular press might have you believe, it would be impossible to open the door in flight.
Fr J Hackett
Well-Known Member
What's the outside pressure
wonkywinch
Well-Known Member
At 41,000 about 2.5 psi so delta is 9-10 psi so better knock 20% off my calcs.
Been almost 3 years since I flew the 787
