World's OFFSHORE VESSELS

[Clipper]

... Welding, doping and X-ray stations are still not in place, only Tensioners and Rollers. ...

Ombugge, please allow me to reveal my ignorance. What is "doping" please.

Clipper

[ombugge]

Ombugge, please allow me to reveal my ignorance. What is "doping" please.

Clipper

Whaaat!!!, you don't have dope heads around your part of the woods???

In pipe lining terms "doping" means the external coating, which may be concrete to add weight, or some form of protective coating to avoid corrosion, or both.

In any case, once the 40 ft. sections of pipe (with covering already in place) have been welded together, X-rayed and approved, the gap at each weld has to be "doped" before it goes out over the stinger. (I.e. the area of weld have to be covered as well)

The order should actually have been; "Welding, X-ray, Repairs and Doping stations", because if a fault is detected at the X-ray station, the weld has to be repaired, re-checked and approved, before it can receive "dope".

One important item of equipment which I forgot to show is the "Abandon and Recovery (A/R) Winch":

This is used to lower the pipeline end to the seabed in a controlled manner and under tension. Usually because of adverse weather or whatever emergency situations.
It is also used to pull the pipeline end back on board when the problem is no longer there, as the name indicate.

[pakarang]

Did anyone see this offshore vessel with newly installed heli deck, on Maasmondmaritime newsletter today?

[ombugge]

Did anyone see this offshore vessel with newly installed heli deck, on Maasmondmaritime newsletter today?

There is a bit of an issue with stability on the NOR Tigerfish after adding the Helideck and a large A-frame.

Not surprising you may say when looking at this picture, but the issue was more on the way the inclination experiment was conducted and controlled by the conversion yard. (Sorry, no details can be posted here)

[Germen]

Vos Satisfaction: Type of ship: Cargo Ship
IMO Number: 9352224 Flag: Netherlands
MMSI Number: 244626000 Length: 58.0m
Callsign: PHKK Beam: 16.0m


Here new photo from de Vessel: Vos Satisfaction.
Harbour Harlingen 5-3-2010

Regards Germen

[pilotdane]

Did anyone see this offshore vessel with newly installed heli deck, on Maasmondmaritime newsletter today?

I wonder if there is a check box for "just too wierd or ugly" that an engineer uses when inspecting a conversion/refit?

How much lead do you have to bolt to the keel to balance all that helicopter deck steel? I can imagine that large a structure puts a huge strain on the hull and attach points. The heavy engine & fuel trying to keep her upright and that big helicopter deck sail trying to turn her over and the poor hull is caught in between.

[Clipper]

How much lead do you have to bolt to the keel to balance all that helicopter deck steel? I can imagine that large a structure puts a huge strain on the hull and attach points. The heavy engine & fuel trying to keep her upright and that big helicopter deck sail trying to turn her over and the poor hull is caught in between.

I wonder if the helideck looks a bit smaller in a photo taken further away with a standard lens? In the photo above, it looks like a serious wide-angle and viewpoint were chosen to show off the helideck.

I failed to find a better image but found this instead, which suggests that the majority of the structure is aluminium. However, if I was on board I would still like reassurance that all the CofG calculations and strength modelling of the attachment points had been done correctly.

Clipper

[ombugge]

I wonder if the helideck looks a bit smaller in a photo taken further away with a standard lens? In the photo above, it looks like a serious wide-angle and viewpoint were chosen to show off the helideck.

I failed to find a better image but found this instead, which suggests that the majority of the structure is aluminium. However, if I was on board I would still like reassurance that all the CofG calculations and strength modelling of the attachment points had been done correctly.

Clipper

That is correct Clipper, only the support structure (painted white) is
steel, the deck itself is aluminium.

How much lead do you have to bolt to the keel to balance all that helicopter deck steel? I can imagine that large a structure puts a huge strain on the hull and attach points. The heavy engine & fuel trying to keep her upright and that big helicopter deck sail trying to turn her over and the poor hull is caught in between.

Actually the calculations shows she doesn't require any fixed ballast for this conversion. My contention is that Naval Archs only appears to consider windage forces acting on helidecks when the vessel is on even keel, not when listed.

[ombugge]

Here is a pics of NOR Tigerfish WITHOUT the Helideck, but with the 50 m.t. SWL A-frame and the Mezzanine deck installed:

[Clipper]

That is correct Clipper, only the support structure (painted white) is steel, the deck itself is aluminium.

On that aluminium-offshore page it says "Helideck with 3m aluminium support structure and platforms". So adding that to what you say, it appears the non-white lattice (deck stiffening structure) is aluminium, not just the deck (plates). It depends on what you include in the definition of "deck".

Actually the calculations shows she doesn't require any fixed ballast for this conversion. My contention is that Naval Archs only appears to consider windage forces acting on helidecks when the vessel is on even keel, not when listed.

If that's right, then it's truly frightening!! I'm sure that windage on a canted deck of that type could be very significant. Wind under the deck gives a positive feedback situation unlike wind on a conventional main deck which provides a righting moment. Scary.

Clipper

[pakarang]

I'm a little surprised that aluminum is used in a heli-deck-construction at all...: burning helicopter fuel and a high-intensity fire would not be good on anything made out of aluminum.

Or, is it safer than what I imagine?

[Clipper]

I'm not an expert Jan-Olav but I think aluminium is safe at the sort of temperatures most pretroleum products burn at. It may buckle and lose strength but so will steel to a greater or lesser extent.

Aluminium is certainly dangerous in a military context in that the higher temperatures associated with weapons can actually cause it to ignite!! I have been told that it happened in at least one ship in the Falklands war (HMS Ardent, HMS Antelope, HMS Coventry, HMS Sheffield?). Remember burning a strip of magnesium in chemistry lessons at school? Well apparantly aluminium goes the same way - very bright and highly exothermic. I guess the flash point varies from alloy to alloy.

I read lots on Piper Alpha in the past but don't recall any reports of it in that incident but maybe Piper Alpha didn't have too much aluminium.

Maybe Ombugge knows if aluminium ignition has been known in the the offshore industry.

Clipper

[ombugge]

Here is a link to the manufacturer of the helideck installed on board the NOR Tigerfish; http://aluminium-offshore.com/news-r.../nor-tigerfish

These Helidecks has a built-in Fire Fighting System based on water only, while there are other designs which incorporate foam as well.
At what temperature Aluminium ignites I'm not sure, but if it could happen at a temperature within the range developed by burning Avgas it would not be approved for use in Helidecks for offshore installations.

I have never heard of any cases where aluminum has ignited in any Oil and Gas related incidents, but then there aren't much that is built from aluminum on a rig or platform.

By the way; Helicopters and airplanes are made from aluminum, aren't they???

[Sterkoder]

Yesterday it finally cleared up a bit in the afternoon, the sun came through and the sea became calm. Not many vessels to take pictures of, but as "Skandi Captain" entered the harbour via the Markussundet Inlet, I fired of a couple of shots


Today, it was back to rain, low stratus clouds, fog and some wind...., as you can see on my images of "Bourbon Mistral".
This is a stand-by/supply vessel delivered from Ulstein Yard in 2006, but as she has sailed in distant waters since then, this is my very first pictures of her as she now has Kristiansund Base at Averøy as her base.


We don't have a wreck like the one in Tromsø here, but an old fence would play the role

[Sterkoder]

Stand-by vessel "Ocean Sky" at dock #9 down at Vestbase this morning


"Far Seeker" at dock #7 - Vestbase


"Stril Poseidon" over at Kristiansund Freeze Terminal

[Steve.B]

I like the look of the "Stril Poseidon", great looking vessel! But i have to say that i have still not got used to seeing or accepting the Xbow, in my eyes the "Bourbon Mistral" looks plain butt ugly.

[Sterkoder]

I like the look of the "Stril Poseidon", great looking vessel! But i have to say that i have still not got used to seeing or accepting the Xbow, in my eyes the "Bourbon Mistral" looks plain butt ugly.

The Mistral is ugly, I agree, because she's designed purely as a lorry. Notice her short distance from bow to where her loadingspace starts.
The Mistral is made as a supplyvessel.

Then we have tha Bourbon Orca, which has a slightly longer superstructure.
She's designed as a tug/anchor handler and supply vessel and need a little less space on deck. I belive she has a certain beauty to her.

Then we have the x-bow construction vessels, with helideck and a long bridge/superstructure, like "Viking Poseidon". They are downright tough, in my personal view.
Seen here in the image of Ole Fuglestad/Skipslisten


But I agree with you clearly: Bourbon Mistral is not exactly a beauty to watch.

[Clipper]

...... in my eyes the "Bourbon Mistral" looks plain butt ugly.

She reminds me of one of those 1960s Commer pickups :





Clipper

[ombugge]

She reminds me of one of those 1960s Commer pickups :





Clipper

Just a larger version, minus the wheels.
The purpose is the same, optimum cargo space on the "deck".

[Clipper]

Just a larger version, minus the wheels.
The purpose is the same, optimum cargo space on the "deck".

I agree, but do we know that Bourbon Mistral doesn't have wheels!!?