Author Topic: Can a ship float upside down / turned turtle?  (Read 946 times)

0 Members and 2 Guests are viewing this topic.

Online Isabelle Prondzynski

Can a ship float upside down / turned turtle?
« on: Mar 14, 2022, 09:56 PM »
I have just started reading the "Poseidon Adventure" by Paul Gallico. The film has been mentioned in the Forum several times, but have you read the book?

I have not got very far yet, but it seems to me that Paul Gallico must have tried at least to inform himself about large passenger ships.

Written in 1969... QE2 probably did not serve to provide the details.

Incidentally… can a ship really float upside down, even for a while?
« Last Edit: Mar 15, 2022, 08:49 AM by Isabelle Prondzynski »

Online Peter Mugridge

  • Queens Grill Diner
  • *****
  • Posts: 3587
  • Total likes: 3412
  • At Mach 2 three days after being on QE2...
Re: Can a ship float upside down / turned turtle?
« Reply #1 on: Mar 14, 2022, 10:25 PM »
Incidentally… can a ship really float upside down, even for a while?

Yes, it's possible - it all depends on how much air is trapped in the superstructure and what the center of gravity is.  In most cases, though, I'd expect a capsize rather than a turning turtle to be the outcome of any major instability, considering how much weight is usually low down in the hull.
« Last Edit: Mar 14, 2022, 10:27 PM by Peter Mugridge »
"It is a capital mistake to allow any mechanical object to realise that you are in a hurry!"

Offline skilly56

Re: Can a ship float upside down / turned turtle?
« Reply #2 on: Mar 15, 2022, 04:18 AM »
Ah - Peter. A capsize is the same as 'turning turtle'

All ships sink differently.
When the Bismark sank, she initially 'turned turtle', and at some point during the dive to the bottom, all the main battery turrets fell out of the barbettes. This then changed the hull's centre of gravity markedly, so she then turned upright again while still heading downwards, and hit the sea bed at quite a speed, and eventually stopped in the upright position. Her speed was adjudged to be about 20+ knots when she hit the seabed, defined by the depth and length of the large ditch she left behind her. As the seabed was sloping down at that point, she didn't lose her momentum very quickly.

However, some ships that were sunk in the battle of Jutland have been found on the sea bed totally inverted. Go figure?
And I have just read that the old US battleship 'Nevada' has now been found, 3 miles down on the seabed near Hawaii, with the bow & stern missing, but the main hull portion totally inverted. But she was shelled, bombed, and finally torpedoed by the American armed forces to try and sink her as she was so highly radioactive after being a main target in the nuclear bomb tests off the Marshall Islands.

Looking at the 'Endurance', which has just been found, she is sitting nearly upright at 3,000 ft down. The fact that all the masts & topweight was broken from the ship when she sank virtually ensured she would stay upright on the way down, even though one side of the hull had been pushed in so far it was actually aligned vertically above the keel. We know this from her captain having taken copious notes before the ship finally sank.

Most pax vessels, because of their vertical centre-of-gravity position (VCG), also end up sitting upright on the seabed so long as the hull hadn't been opened up and a lot of machinery weight had fallen out (eg- Mikhail Lermontov is sitting nearly upright in Port Gore, and didn't lose any weight. She gained weight through flooding).

Costa Concordia was different, because the lack of water depth prevented the hull finally assuming a free position on the sea bed.
« Last Edit: Mar 16, 2022, 08:02 AM by skilly56 »

Online Peter Mugridge

  • Queens Grill Diner
  • *****
  • Posts: 3587
  • Total likes: 3412
  • At Mach 2 three days after being on QE2...
Re: Can a ship float upside down / turned turtle?
« Reply #3 on: Mar 15, 2022, 09:28 PM »
Oh right, I had thought, until you wrote that, that strictly speaking capsizing was on the side and fully inverted was turning turtle.

I wonder if the original question could be answered by a computer simulation if it was set up with the correct weights and proportions...?

"It is a capital mistake to allow any mechanical object to realise that you are in a hurry!"

Offline PaulInuk

Re: Can a ship float upside down / turned turtle?
« Reply #4 on: Mar 25, 2022, 01:07 PM »
Only in australia

Offline Trevor Harris

Re: Can a ship float upside down / turned turtle?
« Reply #5 on: Mar 27, 2022, 09:47 AM »
Maybe? Surely not for long? At some point the heavy machinery at the bottom of the ship would end up weighing it down enough to sink completely?
Enjoyer of classic cinema, literature, and music.

 

Dutch sail training ship Astrid wrecked off Kinsale in Ireland

Started by Isabelle ProndzynskiBoard Sea Shanties

Replies: 3
Views: 2063
Last post Jul 29, 2013, 10:10 AM
by Isabelle Prondzynski
someone know this ship and her story?

Started by luzparisBoard Ships

Replies: 10
Views: 2052
Last post Jan 12, 2011, 09:30 PM
by Bob C.
Recent Visit to the ship (SS United States)

Started by TonyBoard SS United States

Replies: 4
Views: 1883
Last post Oct 04, 2019, 01:47 PM
by ChrisUK
Poll August 2020 : QE2 with a boat or ship as escort

Started by Isabelle ProndzynskiBoard Archived Topics (older calendars)

Replies: 19
Views: 1983
Last post Oct 01, 2020, 04:37 PM
by Rod
ps Waverley Techy Matters! (Info, Q&A on the technical side of the ship)

Started by Clydebuilt1971Board PS Waverley

Replies: 29
Views: 18097
Last post Jan 05, 2015, 06:04 PM
by June Ingram