BS: Seamanship

Subject: RE: BS: Seamanship
From: Gareth
Date: 10 Feb 04 - 10:45 AM

Actually - This reminds me of a "Funny Ha-Ha" that is some years old.

Now these submersible lift ships are fine, and will go up and down with the regularity of an express lift, providing of course that the hull what goes under the water maintains its watertight integrity.

Some 20 years ago a Semi-Submersible (Wijsmuller BV's "Super Servant Two") was delivering a drilling rig to the mouth of the Congo River.

No problems with the voyage and the ship prepares to submerge to allow the rig to float off.

Down goes the ship, the order 'cease flooding' is given, but the ship continues to sink. Crew etc hastily appear on the superstructure and take to the liferafts. And with a "Glugging" noise the Semi-Submersible is now fully submersed.

Yup - You guessed it, some BF had left a hatch open,. normally above water, but when she submerged this hatch went below the Water line.

Gareth

Subject: RE: BS: Seamanship
From: Teribus
Date: 10 Feb 04 - 10:15 AM

Rapaire,

The idea originally came from a requirement to find a more cost effective way to transport semi-submersible drilling rigs to different locations round the world.

Heavy weather is not a problem, that is addressed in design of grillage and seafastenings. Routes are carefully worked out and alternative safe-havens are identified along that route. Prior to departure everything is checked and the vessels in the towing spread and the heavy transportation barge itself receive weather forecasts, looking five days ahead, at minimum 12 hour intervals from at least two independent sources.

Equally impressive are the heavy lift barges, biggest in the world is Saipem 7000, a dynamically positioned (does not need anchors to stay in position) semi-submersible barge equipped with two 7000 tonne cranes allowing a tandem lift of 14,000 tonnes.

Subject: RE: BS: Seamanship
From: Rapparee
Date: 10 Feb 04 - 09:22 AM

Actually, the idea that it can be done at all impresses me. I would have thought that they'd have plugged the hole with mattresses and welded plate on as best they could, requisitioned a bunch of buckets, and prayed for glassy seas.

Yet I've seen drilling platforms being built and under tow.

I doubt that I'll set foot on any water-borne vessel before next September (I'm going on a small ship cruise then).

Just the idea impresses me -- and if during the transport they HAD run into heavy weather....

Subject: RE: BS: Seamanship
From: Gareth
Date: 10 Feb 04 - 08:24 AM

Yup Dave - HMS Nottingham Click 'Ere

Gareth

Subject: RE: BS: Seamanship
From: Dave Bryant
Date: 10 Feb 04 - 05:29 AM

Didn't the Royal Navy have one of their ships transported home recently in a similiar fashion, after she hit a rock ?

Subject: RE: BS: Seamanship
From: Teribus
Date: 10 Feb 04 - 04:11 AM

For that type of submersible barge the USS Cole is a very light weight, but awkward shape. They are normally used to transport completed top-sides modules of offshore platforms from construction yard to the offshore installation site, some have the capacity for 25,000 tonnes. For ocean passages with a heavy deck-load these barges are amazingly stable, out of yards in Korea and China, the grillage and seafastenings have to be able to withstand typhoon conditions.

If you take the upper case H and view that as the offshore platform, the barge manouevres between the upper two columns and them submerges to mate the topsides module with the structure. Depending on the design engineering, this type of installation is possible in seastates up to Hs 2m (Significant wave height of 6.6 feet, or maximum wave height of just over 11 feet).

Subject: RE: BS: Seamanship
From: dianavan
Date: 10 Feb 04 - 02:16 AM

I'm impressed! I get nervous even trying to put a boat on the ways and I really hate being in drydock!

d

Subject: RE: BS: Seamanship
From: Amos
Date: 10 Feb 04 - 12:02 AM

Don--

I was estimating that 5 feet would be a minimum of interference, in trying to get the Cole onto her while she was submerged. But, fine, say bigger. Crossing the Atlantic on piggy back is what the floater was designed for, and as long as the weather was balmy, it looks like pretty easy duty once the cargo was lashed down. Gawd save them if the glass fell, though, because that thing doesn't look very kindly at all.

A

Subject: RE: BS: Seamanship
From: DonMeixner
Date: 09 Feb 04 - 11:58 PM

Amos,

I doubt a five foot swell would be much trouble for that floating dry dock. The depth was a bigger issue that the wave action. Blue Marlin is a semi-submersible and needed an additional 75' of draft to manuver into place under the Cole before she could be lifted.   

The USS Cole was then drug home and into the gulf for repairs at Pascagula. Just crossing the Atlantic on a piggy back is very impressive indeed.

Don

Subject: RE: BS: Seamanship
From: Amos
Date: 09 Feb 04 - 10:25 PM

Nice pictures,god-awful terrible poetry; as to the seamanship, it is a Force 0-1 condition, so it is pretty straightforward as far as any seamanship is concerned.

I'd be a lot more impressed if they pulled that off in a 5-foot swell, let alone something worse.

Ask Kendall -- he's had many more sea miles than I have and he'll tell ya about the same, I guess.

A

Subject: RE: BS: Seamanship
From: JudyB
Date: 09 Feb 04 - 10:05 PM

Frightful damage!

Charley Noble

Subject: RE: BS: Seamanship
From: Peace
Date: 09 Feb 04 - 10:05 PM

Thanks, Rap. Beautiful and awesome.

Subject: RE: BS: Seamanship
From: MarkS
Date: 09 Feb 04 - 09:52 PM

Awsome technology. Even more awsome is that we all seem to take it for granted.

Subject: BS: Seamanship
From: Rapparee
Date: 09 Feb 04 - 06:54 PM

Maybe it should be seapersonship. Anyway, I'm not a sailor but I am impressed by good sea savvy -- and good engineering like this.