Marine airbags -Interview with Evergreen Maritime (3)

What was the most challenging mission your system has assisted with?

The most challenging mission we ever participated is the ancient ship named “Nanhai No.1” salvage project. That salvage project is called the most complicated and expensive one in China history.

The salvage project had been revised for 6 times and been demonstrated for 4 times during the preparing 4 years. At June 2006, the top 22 experts were collected to demonstrate the latest project which got approved after two days discussion. The spirit of salvage project is to build a large caisson to contain the ship and its surrounding then lift the caisson out of water and land by marine airbags.

The Nanhai No.1, weighs 2,800 tons under the water. When brought out of water, it will weigh some 4,800 tons. The caisson was brought out water and placed on a submerged barge then carried to a temporary port. All we need to do with marine airbags is land the caisson from the barge and move it to its final residence, a specially built museum named "crystal palace". The tides and droping off weights along with the caisson move to land make the barge’s working height and directions changed every time. We have to adjust the inner pressure of marine airbags placed under the saisson to redirect caisson to close the port or change the height of caisson bottom to reach the better condition for landing. On 12/25/2007 The first attempt to land the caisson was cancelled because of the violent wave when the caisson near the port 4 meters. During the next day’s floodtime, It took more than 3 hours to land the caisson on the temporary port successfully with 16 huge air bags. The left 365 meters from the temporary port to museum is comparative easier for air bag to carry the caisson to make it. On 12/28/2007, the caisson arrived its new home "crystal palace"and the mission of our company finished.

Experts said there were four cutting-edge tools ensure the success of this salavge project ,Evergreen marine airbag was one of them. Marine Airbag can offer the best protection to the ancient ship held in the caisson during the process of land and transportation. Its safety and flexibility was highly praised by experts and officers.

Is your company working on any new ideas for the future?

Yes. As we mentioned before ,marine airbag ship launching technology can not be used for ship side-launch now. We are working hard on improvement of marine airbags and new project designing for ship side-launch with marine airbags. We have two aims to achieve in the near future: one is enable ship side-launch with marine air bags,another one is to launch the DWT 100,000 ships with marine air bags.

How can we learn more about the product?
We think our website :http://www.evergreen-maritime.com is a good way to learn more about marine airbags. We have plenty of airbag ship launching/salavge cases presented in our website which are helpful for people to know about the product.

Marine airbags -Interview with Evergreen Maritime(2)

They look very similar to Yokohama Fenders, how do they differ?

The main use of Yokohama fenders and Evergreen marine airbags are definitely different. It is well known that Yokohoma fenders are used in effective fender system providing a soft and stable berthing condition to ships. And Evergreen airbags are widely used for ship launching,landing,heavy transport and air lifting. Due to the special use, structures of Evergreen airbags are optimize to heavy duty and safe. The surface layers are enhanced for anti-abrasion and pierce resistance ,even they are somewhat wounded Evergreen airbags can still work safely untill recoverd by repaire. The lengths of airbags are usually more than 10 meters and two cone-shaped ends make them look like huge sausages. And Evergreen air bags never use tyres and shackles.

What are the advantageous to using this system over traditional ship launching techniques?

Marine airbag ship launching system do not need the traditional fabricated slipways so it saves time,investment,land etc. Air bags need no more extra maintenance,after use they can be cleaned and folded in the corner to wait for another mission. It is easy to find that airbags’ elasticity can give more protection to the launched ship. The remarkable character of airbags is that they can change the working height to redirect the ship or any being launched object by adjusting their inner air pressure. For this character it is peerless campare to traditional ship launching techniques.

Are there other uses for this system?
Evergreen ship launching airbags are not only uesd for ship, floating dock,caisson launching but also on cutting edge in ship landing,heavy transport , marine salvage etc. It is a versatile tool for many marine applications.

Marine airbags -Interview with Evergreen Maritime (1)

What were the first uses of marine airbags in the launching of ships?
People can trace the history of airbag ship launching back to 1981 year,over 20 years ago. Xiao Qinghe ship repair and building shipyard,located in Jinan city of Shangdong Province, launched a 60 DWT tank barge with marine airbags on Janu. 20, 1981. Seven marine airbags were employed in that ship launching project,one is 2 meters in diameters and 6 meters long used for elevating and the left six air bags are 0.8 meter and 6 meters long act as the rollers. The initial intention of that ship launching trial is for warfare purpose to develop a prompt,less landform limited ship launching method.

How has the technology advanced since then?
During the past over twenty years, the marine airbag ship launching system make progress not only the airbag but also the ship launching/landing technology.
The first generation airbags use rubber dipped canvas as reinforcement layer , the trunk and two cone-shaped ends are made separatelly. People lapping rubber and dipped canvas to form the air chamber trunk and stick strips to molds to make the air bags’ ends ,then stick them together.
The latest marine airbags use the rubber dipped synthetic-tyre-cords as the reinforcement layers and take the whole-enlacing-technology for manufacture. The trunk and two cone-shaped ends are made at the same time and enlaced together so the whole air bags have no joints. Due to the development of rubber chemistry the performance of rubber employed in the latest air bag is highly enhanced also. The performance of the latest airbag is 15 times of the first generation one with the same specification.
Regarding the launching/landing technology, it developed most during the past 20 years. From the beginning, only small and flat bottom ship located in fabricated slope can be launched with air bags. And now this technology is more flexible and less limited by the ship and landform. Any type of ship DWT below 55,000 at a place with enough launching space to the water can be launched with air bags. And the launching slope even can be aclinic. The air bag ship landing technology developed from applications in some stranded ship salvage projects and then it comes into a cutting edge one especially useful for some marine emergencies.
http://www.evergreen-maritime.com

Malaysia says first submarine unable to dive

Kuala Lumpur: Malaysia's first submarine, a European-made Scorpene delivered last September, has developed problems that make it unfit for diving, the defence minister said Thursday.

The KD Tunku Abdul Rahman sailed into a grand reception last year as the first of two commissioned from French contractor DCNS and Spain's Navantia for a total of 3.4 billion ringgit (961 million dollars).

Named after the country's first prime minister, it was hailed as an important acquisition despite opposition allegations of corruption in the deal.

"The submarine can still dive but when we detected the defects, we were advised that it should not dive," Defence Minister Ahmad Zahid Hamidi told reporters.

"The (parts found with) defects are still under warranty so the supplier and contractor are repairing them," he added.

Navy chief Abdul Aziz Jaafar said a problem first emerged in the submarine's cooling system last December. After being fixed, another defect was identified in a different system last month.

"We hope it can dive again after February 18 so we can carry out the tropical water trials," Abdul Aziz told reporters.

The navy chief said the second submarine, the KD Tun Razak which is named after the nation's second premier, is expected to arrive from France on May 31. It was originally scheduled for delivery in late 2009.

The two submarines have attracted controversy since the deal was signed in 2002.

Malaysia's opposition claims that a 540-million-ringgit commission was paid to a close associate of Prime Minister Najib Razak in brokering the contract.

Najib has denied there was any corruption in the deal, which was made when he was defence minister.


---------------------------------------------------------------------------------SOUNDS LIKE A JOKE,,,

DWT 58,000 Cargo Ship Launching with Evergreen Marine Airbags

On 1 Feb. 2010 Qingdao Eversafe Marine Engineering Company (www.eversafe-marine.com) flawlessly launched a DWT 58,000 cargo ship with Evergreen airbags in Zhejiang China and this launching project sets the new world record of airbag ship launching.
This cargo ship holds 11,800 tons is 199 meters long and 32 meter wide. It is built on a 0.87 degree concrete ramp whose end is a sluice gate. From the water gate to ship’s stern is 15 meters and the water beyond the gate is 8 meters deep. Total 76 pieces Evergreen airbags are employed to complete this project and also two 25 tons winches.
For big ship launched with marine airbags, the scientific design from calculation is vital for success. To ensure this DWT58, 000 cargo ship’s safe launching, there are two conditions must be satisfied first: avoiding the “bow decline” during the launch process and the rush distance is controllable when ship is after launch.
Evergreen experts are gathered to calculate the launching project of the largest ship ever be launched by marine airbags. From mathematic modeling to computer simulation every step of launching process are researched carefully. From the water level to weather variety most conditions are considered for the design. When settle the arrangement of marine airbags Evergreen engineers find the stern rope must be added to control the rush of ship after launch. So 4 stern ropes are demanded to fix on the bollard of a floating dock with 45 degree angle to the ship and the time of cast anchor is also stated.
At 31 Jan. Qingdao Evergreen Maritime completed the ship raise and most block remove work. At that time two winched pulled ship from slipping and the blocks under stern remained. The highest tide of 1 Feb. is estimated to occur at 10:30 AM, so launch time is decided to be 10 AM. At 9:30 am Evergreen team began to adjust the inner pressure of airbags at stern to be 0.12Mpa and then released the steel ropes from winches. At 9:50 airbags under gravity center and bow were inflated to be 0.15Mpa then the ship began to move slowly by riding rolling airbags. During the launch process the ship’s incline angle is increasing until the stern floated when the bow enters into deep water already. There is no “bow decline” phenomena occurred just as forecasted by calculation.
When ship advanced in the sea for a certain distance its bow anchors was casted and four stern ropes were trained. So ship moved sideways then it was pushed by two tug boats to mooring.
The success of DWT 58,000 ship launched with Evergreen airbags not only creates a world record of airbag ship launching but also means the airbag ship launching technology reaches a new altitude. Evergreen Maritime is devoted to the marine airbags’ manufacture and launching technology development for more than 10 years so he achieves today’s accomplishment.
Qingdao Evergreen Maritime is never satisfied and forever on the go.

Evergreen airbags successfully launched a 32,500DWT Bulk Carrier

On 16th.Jan.2010, the 32,500DWT Bulk Carrier “NO. 6 Dongze” was successfully launched by Evergreen ship launching team with Evergreen Marine Airbags in Nanjing Dongze Shipyard. It is the sixth ship launched by Qingdao Evergreen Maritime Company using airbag launching technology for this shipyard.
This Bulk Carrier with 210 meters length and 34 meters molded breadth weight 9,500 tons. January is the dry season of the Yangtze River Valley, so there is long distance between the stern with the tide point. Fortunately the launching slipway was initially constructed in the light of Evergreen team’s design, so the calculation of launching start point came to be easier. Finally the ship was moved forward about 30m to reach the best launching point by the control of mooring winches.
Total 64 pieces Evergreen Marine Airbags D1.5xEL18 (YT-6) were employed to launch this Bulk Carrier. And all airbags’ inner pressures were adjusted to the required value before the launch. After a simple ship launching ceremony, the workers cut off the wire ropes to release the ship. Then the Bulk Carrier went into river by riding marine airbags smoothly. Different from the traditional end-on ship launching, the “stern dipping” and “stern rising” phenomena are not obvious anymore during airbag ship launching.
Qingdao Evergreen Maritime is preparing another 55,000DWT vessel launching project which will be performed after three weeks. Keep an eye on our website www.evergreen-maritime.com to know the latest news.

Hydraulic burst test of Evergreen Marine Airbags

Hydraulic burst experiment is the ultimate test for the Marine Airbags’ performance, material, manufacturing technique and structure type. Meanwhile, Hydraulic burst test also can be used to confirm the safety working pressure. But, there hasn’t been any other manufacturers done this test with regular products because of the high cost and lacking of confidence of their airbags’ performance. Generally they employ a small size airbag to do the hydraulic burst experiment and then infer to all sizes.
At the request of research department of China Shipbuilding Industry for the amendment of CB/T3795, Evergreen-Maritime did this “Hydraulic burst test” with regular Evergreen Marine Airbags. As per the requirement of industry standard, we randomly selected three pieces D1.5xEL8m YT-6 type Evergreen Marine Airbags to do the bursting test orderly under the same condition.

The result is as follows:
For the first Marine Airbags, the Hydraulic bursting pressure is P1= 0.73 MPa
For the second Marine Airbags, the Hydraulic bursting pressure is P2=0.71Mpa
For the second Marine Airbags, the Hydraulic bursting pressure is P2=0.72Mpa
Thus, the average bursting pressure is P= (P1+P2+P3)/3= 0.72 Mpa.

Then we select the safety working factor 6 (the industrial standard demands this factor for 4.5)
Pe = P/n= 0.72 Mpa / 6= 0.12 Mpa

Thus, we define the “Safety Working Pressure” of YT-6 type Evergreen Marine Airbags with 1.5 m diameter as 0.12 Mpa. For airbags with other diameter sizes, we did the same Hydraulic burst experiments to define the safety working pressure data.
To get more information, please don’t hesitate to contact us by sales@evergreen-maritime.com