Model Boat Mayhem

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: Oh Heck!  (Read 3046 times)

boatmadman

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,718
  • Location: South Cumbria
Oh Heck!
« on: June 13, 2009, 06:28:58 am »

Think they overpumped the ballast tanks!
Logged
if at first you dont succeed.....have a beer.....

DickyD

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 9,497
  • www.srcmbc.org.uk
  • Location: Southampton UK
    • SRCMBC
Re: Oh Heck!
« Reply #1 on: June 13, 2009, 09:53:05 am »

You missed these two Ian



Logged
Richard Solent Radio Controlled Model Boat Club http://www.srcmbc.org.uk

portside II

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,523
  • tugs at rest
  • Location: Howden.East Riding of Yorkshire.England Near the banks of the river Ouse
    • goole model boat club indi site
Re: Oh Heck!
« Reply #2 on: June 13, 2009, 12:31:57 pm »

Will yours do that ?  {-)
daz
Logged
I like to build my boats to play with, not to just look pretty,so they dont !

boatmadman

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,718
  • Location: South Cumbria
Re: Oh Heck!
« Reply #3 on: June 13, 2009, 01:59:29 pm »

Hope not Daz  :o
Logged
if at first you dont succeed.....have a beer.....

BarryM

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,692
  • Location: West Lothian
Re: Oh Heck!
« Reply #4 on: June 13, 2009, 03:08:28 pm »

Logged

Navy2000

  • Guest
Re: Oh Heck!
« Reply #5 on: June 13, 2009, 10:02:22 pm »

They were very lucky that no one died during this event. I guess that the crew knew some thing was wrong and moved to locations to get off the boat quickly.

Duane
Logged

over_powered84

  • Guest
Re: Oh Heck!
« Reply #6 on: June 15, 2009, 03:56:01 pm »

They were very lucky that no one died during this event. I guess that the crew knew some thing was wrong and moved to locations to get off the boat quickly.

Duane
It Was Lucky For The MS3 Crew But Unforunate For Her Sister Ship MS1 Which Lost All Hands, I Wanted To Build The Blue Swan Thinking No-One Would Have Done That Before Little Was I To Know Someone On Here Done Her Lol, So i Now Have Another Project On The Boards....*Top Secret*
Logged

Bryan Young

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 6,893
  • Location: Whitley Bay
Re: Oh Heck!
« Reply #7 on: June 15, 2009, 05:44:27 pm »

Although the pics by themselves are "impressive", and on the assumption that somebody is now looking for another job, I have a question.
Is there a demarcation line (however finely drawn) as to when a surface vessel becomes a sub-surface vessel? U-Boats were designated as "boats" with a submersible ability.
The type of vessel (mega heavy lift and "semi" submersible) shown in the pics must share some of the stability and buoyancy problems encountered by "true" submarines. To attain neutral buoyancy the limits must be very fine and precise. Even a couple of tons (2 cubic yards) of extra weight could well spell "disaster". Just a thought. BY.
Logged
Notes from a simple seaman

warspite

  • Guest
Re: Oh Heck!
« Reply #8 on: June 15, 2009, 07:29:35 pm »

Crash dive springs to mind (taken from silent hunter 3)  :D

or

Where did you say that water level line was
Logged

Bryan Young

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 6,893
  • Location: Whitley Bay
Re: Oh Heck!
« Reply #9 on: June 15, 2009, 07:58:39 pm »

Crash dive springs to mind (taken from silent hunter 3)  :D

or

Where did you say that water level line was
Oh dear, and here was simple little me thinking I might get a sensible answer.
Logged
Notes from a simple seaman

gondolier88

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,351
  • www.coniston-regatta.co.uk
  • Location: Crake Valley, Cumbria
    • Coniston Regatta
Re: Oh Heck!
« Reply #10 on: June 15, 2009, 09:05:41 pm »

Hi Bryan,

Perhaps main ballast tanks to take her to limit and say maybe 3 or 4 small (ton?) ballast tanks amidships with high capacity constant inlet/ outlet capabilities???

I am uninitiated in the wonders of modern semi-subs but just the way I would go about it.

Greg
Logged
Don't get heated...get steamed up!

warspite

  • Guest
Re: Oh Heck!
« Reply #11 on: June 15, 2009, 10:34:57 pm »


Oh dear, and here was simple little me thinking I might get a sensible answer.
[/quote]

Sorry couldn't resist it  :embarrassed:
Logged

BarryM

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,692
  • Location: West Lothian
Re: Oh Heck!
« Reply #12 on: June 15, 2009, 11:06:51 pm »

Bryan,

I have considerable experience of non-submersible offshore transport barges but the intent with those was always to keep them above water and to that effect ballast plans for the loaded condition were always checked and independently double-checked before approval.

First generation semi-sub cargo barges were non self-propelled and had fairly basic ballasting systems often using pumps for ballasting and pumps/compressed-air for deballasting but they did not submerge to quite the extent that the Super and Mighty Servant Class vessels do. The later vessels became bigger, self-propelled and able to submerge further but - as far as I am aware - ballasting systems remained fairly low-tech.

The big semi-sub, twin-hull, crane vessels used offshore with lift capacities ca. 20,000 ton have very sophisticated, high-capacity, ballasting systems which are computer controlled to provide rapid reaction to the application of big hook loads. I put this info in here because I wonder if something similar, although not as sophisticated, may be in use on the current generation of semi-sub barges.

As you would expect, the residual buoyancy in the semi-sub barges lies partly in the submerged stern of the barge, fine-tuned to stop it going right down (supplemented by the demountable tower tanks fitted aft when this does not interfere with the cargo) and the forward accommodation/machinery/bridge tower structure. A delicate balancing act that I'm glad I never had to cope with.

Some heavy-lift semi-sub jobs converted from tankers retain the aft superstructure and foc'sle and use side-loading, Thus I would expect these to retain far better stability and reserve buoyancy than the all-for'd types.

Does this help?

Cheers,

Barry M
Logged

boatmadman

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,718
  • Location: South Cumbria
Re: Oh Heck!
« Reply #13 on: June 16, 2009, 09:11:52 am »

I think one of the biggest stability issues with these things is transverse stability.

In either design, the in built stability is at the bow and stern, transverse stability must be through use of various tankage.

I dont have any real life experience of these things, but having built a model of Blue Marlin, I very quickly came to understand the stability difficulties these things have. The first time the model went in the test tank it would capsize for fun, it was so sensitive.

Even with stabilizing foam added, its very tender and sensitive to wind and ripples (waves).

Ian
Logged
if at first you dont succeed.....have a beer.....

BarryM

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,692
  • Location: West Lothian
Re: Oh Heck!
« Reply #14 on: June 16, 2009, 09:27:54 am »

Ian,

They are all heavily sub-divided with wing and centre tanks. However, it's worth bearing in mind that the 'model effect' comes into play when scaling down. The full size job is considerably less tender.

Cheers

Barry M
Logged

Bryan Young

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 6,893
  • Location: Whitley Bay
Re: Oh Heck!
« Reply #15 on: June 16, 2009, 05:45:03 pm »

To BarryM...thanks, a very interesting post.
During my sea-going "career" I was always more concerned with keeping water out rather than to voluntarily let it in. But I suppose "tankers" (and any other ship, come to think of it) have a degree of sinkage. But in my memory of "stability", the usual rules cease to apply once the deck edge is submerged. I guess "our" calculations were arranged around a rolling ship when only one deck edge was submerged. But I seem to recall that the calculations immediately went from "static" stability to "dynamic"...a different set of "rules" altogether.
Having said that, it's interesting that RFAs "Fort George" and "Victoria" have huge built-in buoyancy structures at the back end....above the main deck, a bit like the semi-submersible vessels we are discussing. But I think these ones are to hold the ship above the water on a temporary basis to allow more time for evacuation and possible salvage. Don't know what would happen to the pointy end though!. BY.
Logged
Notes from a simple seaman
Pages: [1]   Go Up