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The choreography of ship building
Offshore support vessels are becoming more and more densely engineered, especially in the North Sea where the oil majors play a large part in driving the technology relentlessly upward.
The problem is of course that labour is pretty expensive at home in Norway, and cost savings are the order of the day. So, yards like Ulstein tend to ship in modularised sections for assembly in Norway – but of course the inexorable rise in technology has an impact on the whole build process.
The weight itself is nothing to be sneezed at. Since completed ships like the Ulstein’s 130m SX121 design are around 10,750dwt in total, it’s not uncommon for the fully outfitted individual modules to weigh in at over 500 tonnes, explains Jonn Gunnar Bjørkedal of Ulstein.
Further, he explains that there’s a different economic outline to each one as with each contract you are looking at a different argument for each yard: “Cost levels fluctuate a lot with these builds so it is a complicated picture; but yard capacity, time schedule and prices make the decision as to what gets constructed where.”
Interestingly, he points out that Ulstein is now trying to do more of its complicated engineering in Norway itself. However it remains a fact that most of the large steel sections are still either shipped in from the Ukraine or from Gdynia in Poland, ready to be matched with their siblings when they finally come home.
For example, a very recent build saw the Polish Crist yard handling some of the larger steel parts including the whole aft of the ship while the Norwegian yard took on the more outfitted areas of the foreship including the complicated engine section and wheelhouse.
It’s fairly obvious that building like this does create some issues, he admits. To start with, “you have to be pretty certain of your tolerances” but the logistics side presents its own challenges. This leaves Mr Bjørkedal co-ordinating a very intricate dance to bring the sections together.
Mr Bjørkedal explains “it’s not just the steel’s weight that makes a difference” to the logistics process. There are particular issues inherent in the design that makes handling tricky: after all, most of them have compound curves running in three dimensions and moreover, many of them are pre-engineered and outfitted, which adds to their vulnerabilities.
Further, unlike most builds, even when assembled these modules are not designed simply to ‘stand up’ on land but to float, adding another set of stresses to the calculations. Much of the answer lies in the tailor-made steel cradles that are designed to spread the load both across the deck and relieve the high pressure points on these curved modules, but there’s no ‘one size fits all’ solution as, again, they are different for every type of build.
On top of this, the journey itself from the two main yards back to Norway present a challenge. Bringing the hull from the Ukraine takes a month: “You have to tow the hull all the way through the Med, through the channel, and up through the Bay of Biscay which can have bad weather during winter time, so that can delay things too.” On the other hand he adds that the module and hull transports from Gdynia also have some challenges, “but at least this is shorter as it simply comes out through the Baltic and takes around a week”.
Once the sections are offloaded in Ulsteinvik some – often the more complex variety – receive their main outfitting and gain a huge slab of equipment in the process. For example the engine modules are brought in using SPMT multiwheelers for transport into the dock hall followed by using Ulstein’s two, 250 tonne capacity dock hall cranes to lift the modules down on to the dock bed. Then they are packed chock-full of sophisticated and somewhat sensitive gear; it isn’t unusual for these modules to more than double in weight before the final lift.
Seeing it from some distance, the ‘dance’ that brings these structures together in the tight yard space at Ulstienvik is intricate enough. Seen up close, you have to admire the management of these huge, complicated logistics both in and out of the yard.
A round of applause for choreographer Mr Bjørkedal, if you please.
Flexing the muscle
Ulstein’s 67m barge Flex is used both for local jobs and also for tows from Poland. For example, build number 301 currently underway at the yard, will soon see Flex shipping 1,200 tonnes of large steel accommodation modules from the Crist shipyard to Ulsteinvik where most of the outfitting will take place.
Mr Bjørkedal explains that this shipment is built up of four large modules weighing 270 tonnes each, plus four single sections that weigh 63 tonnes apiece. For this load-out, Flex will be floated right into the Crist drydock where the modules will be lifted onboard the barge using the shipyard’s 1,000 tonne overhead travelling crane.
Interestingly, in order to cope with the growing module sizes, a couple of years ago Flex was actually transformed from its original catamaran design to a single-hull barge.
Alongside this Mr Bjørkedal adds it was decided to give the barge a capacity increase to 2,000 tonnes and to strengthen the deck structure so that the 600 tonne mobile crane could be driven straight on. “It wasn’t just the crane and its load, there is an extra few hundred tonnes that you have to allow for the counterweight wagon too” he adds.
He explains that the maximum lifting capacity onboard the barge is 420 tonnes on a 12.0m outreach. However, as the crane boom is modularised, it can be lengthened considerably, so with 84.5 tonnes on the arm it can reach out to 47.6m.
Even though this kind of extension is always kept aligned along the barge and not run crosswise along the beam, Flex’s very accommodating ballasting system is certainly needed in order to keep everything, quite literally, on an even keel.
Source: Motor Ship
The problem is of course that labour is pretty expensive at home in Norway, and cost savings are the order of the day. So, yards like Ulstein tend to ship in modularised sections for assembly in Norway – but of course the inexorable rise in technology has an impact on the whole build process.
The weight itself is nothing to be sneezed at. Since completed ships like the Ulstein’s 130m SX121 design are around 10,750dwt in total, it’s not uncommon for the fully outfitted individual modules to weigh in at over 500 tonnes, explains Jonn Gunnar Bjørkedal of Ulstein.
Further, he explains that there’s a different economic outline to each one as with each contract you are looking at a different argument for each yard: “Cost levels fluctuate a lot with these builds so it is a complicated picture; but yard capacity, time schedule and prices make the decision as to what gets constructed where.”
Interestingly, he points out that Ulstein is now trying to do more of its complicated engineering in Norway itself. However it remains a fact that most of the large steel sections are still either shipped in from the Ukraine or from Gdynia in Poland, ready to be matched with their siblings when they finally come home.
For example, a very recent build saw the Polish Crist yard handling some of the larger steel parts including the whole aft of the ship while the Norwegian yard took on the more outfitted areas of the foreship including the complicated engine section and wheelhouse.
It’s fairly obvious that building like this does create some issues, he admits. To start with, “you have to be pretty certain of your tolerances” but the logistics side presents its own challenges. This leaves Mr Bjørkedal co-ordinating a very intricate dance to bring the sections together.
Mr Bjørkedal explains “it’s not just the steel’s weight that makes a difference” to the logistics process. There are particular issues inherent in the design that makes handling tricky: after all, most of them have compound curves running in three dimensions and moreover, many of them are pre-engineered and outfitted, which adds to their vulnerabilities.
Further, unlike most builds, even when assembled these modules are not designed simply to ‘stand up’ on land but to float, adding another set of stresses to the calculations. Much of the answer lies in the tailor-made steel cradles that are designed to spread the load both across the deck and relieve the high pressure points on these curved modules, but there’s no ‘one size fits all’ solution as, again, they are different for every type of build.
On top of this, the journey itself from the two main yards back to Norway present a challenge. Bringing the hull from the Ukraine takes a month: “You have to tow the hull all the way through the Med, through the channel, and up through the Bay of Biscay which can have bad weather during winter time, so that can delay things too.” On the other hand he adds that the module and hull transports from Gdynia also have some challenges, “but at least this is shorter as it simply comes out through the Baltic and takes around a week”.
Once the sections are offloaded in Ulsteinvik some – often the more complex variety – receive their main outfitting and gain a huge slab of equipment in the process. For example the engine modules are brought in using SPMT multiwheelers for transport into the dock hall followed by using Ulstein’s two, 250 tonne capacity dock hall cranes to lift the modules down on to the dock bed. Then they are packed chock-full of sophisticated and somewhat sensitive gear; it isn’t unusual for these modules to more than double in weight before the final lift.
Seeing it from some distance, the ‘dance’ that brings these structures together in the tight yard space at Ulstienvik is intricate enough. Seen up close, you have to admire the management of these huge, complicated logistics both in and out of the yard.
A round of applause for choreographer Mr Bjørkedal, if you please.
Flexing the muscle
Ulstein’s 67m barge Flex is used both for local jobs and also for tows from Poland. For example, build number 301 currently underway at the yard, will soon see Flex shipping 1,200 tonnes of large steel accommodation modules from the Crist shipyard to Ulsteinvik where most of the outfitting will take place.
Mr Bjørkedal explains that this shipment is built up of four large modules weighing 270 tonnes each, plus four single sections that weigh 63 tonnes apiece. For this load-out, Flex will be floated right into the Crist drydock where the modules will be lifted onboard the barge using the shipyard’s 1,000 tonne overhead travelling crane.
Interestingly, in order to cope with the growing module sizes, a couple of years ago Flex was actually transformed from its original catamaran design to a single-hull barge.
Alongside this Mr Bjørkedal adds it was decided to give the barge a capacity increase to 2,000 tonnes and to strengthen the deck structure so that the 600 tonne mobile crane could be driven straight on. “It wasn’t just the crane and its load, there is an extra few hundred tonnes that you have to allow for the counterweight wagon too” he adds.
He explains that the maximum lifting capacity onboard the barge is 420 tonnes on a 12.0m outreach. However, as the crane boom is modularised, it can be lengthened considerably, so with 84.5 tonnes on the arm it can reach out to 47.6m.
Even though this kind of extension is always kept aligned along the barge and not run crosswise along the beam, Flex’s very accommodating ballasting system is certainly needed in order to keep everything, quite literally, on an even keel.
Source: Motor Ship
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