Eversafe Airbag Ship Launching -37500 DWT Cargo Ship

On May 18 2011 ,Eversafe Marine engineering company successfully launched a 37500DWT cargo ship with 50 pieces marine airbags (pneumatic rollers) in Zhejiang Taizhou shipyard. The vessel named “Dongchengyuan “ measured by 180 m length, 29.2 m breadth moulded and 15.2 m moulded depth. Its lightweight reaches 8000 tons.
The vessel was built on a concrete ramp with 2.3/100 slope. Beyond ramp end there is a 40 m long unpaved dirt ground. The launch channel water is so shallow that in low tide a 30 m long beach full of mud will appear.
The difficulty of this airbag launch project is the deficient launch ramp and launch area that may cause launch accidents. Eversafe engineer calculated the possible bearing pressure of the ground during launch and found the gravel reinforcement would suit for demand. Since time is tight dredging launch area is impossible. So people have to prepare the remedial solution to prevent vessel from getting stuck by mud: one tug boat was employed to help launch.
In the afternoon of May 17, the vessel was transported forward for 40 meters with airbags which can prevent the 40 m long ground from collapse during the launch. In the next day morning Eversafe launch team began to work as early as 6 am. People adjusted all airbags’ pressures to decide vessel’s trim angle according to the design plan. Ropes from tug attached to the stern pole with a 45 degree angle. After the launch ceremony at 8:30 am the launch commander shot the gun .When two pulling ropes were chopped the vessel started to move steadily to the water. Since launch area water was not deep enough to float stern, airbags were pressed more than 60% by stern’s weight. The slippage inertia keep vessel moving but vessel’s speed slowed down until tug’s pull force accelerated it again. When vessel entered into deep enough water it got float freely.
This launch project is a rigorous test of Eversafe launch team and ship launching airbags. Airbags bore about twice pressure than normal launch. Advantages of airbag ship launching are represented clearly by this project: airbag launch can remedy the deficiency of launch condition which is especially useful for some emergent projects.
But a good preparation work can mostly promise the success and safety of airbag ship launching. Only for some special condition people should do the launch with deficient preparation. Also quality of ship launching airbags is the vital factor for the success.

How to select marine airbags for your marine project

Marine airbags are widely used for ship launching, heavy transportation and marine salvage nowadays. Marine airbags are often called ship launching airbags that indicate the most popular application of these heavy duty airbags is for ship launching. It is estimated that more than 80 percent new built ships who’s DWT below 60,000 are launched by marine airbags.
Marine airbags are found to be powerful and versatile tools for many other marine projects such as disembarking ships, heavy transportation, re-floating salvage etc. But how to select suitable marine airbags for a specific project? Let us see suggestions from Eversafe Marine Engineering Company.
Marine airbag's specifications
Select the airbag's effective length not less than the maximum width of vessel or anything you want to move by airbags. But when you arrange two rows of airbags keep in mind to calculate the total length to avoid contact of airbags in two rows. The total length of airbags can be estimated to be effective length plus diameter. It says an airbag whose effective length is 16 meters and diameter is 1.5 m then its total length is 17.5 m.
Diameter of airbag is decided by the height of your vessel's support blocks. If the support block is 1 m high, then you should choose airbag's diameter not less than 1.5 m. If you get 1.5 m high blocks, the airbag with 2m diameters will suits you well.
For air lift use, airbag's diameter or length is mainly decided by the buoyancy you need from airbag. And also consider the pressure of airbag stands if you apply airbags in deep water.
For caisson transport by marine airbags, the most suitable diameter is 0.8-1 m. Marine airbag's performance is decided by its component plies. For air lift use or light vessel (launch weight below 2000 tons) launch, mid-pressure airbags are enough. For heavy duty work, the high pressure airbag should be selected. Generally speaking, airbags with 6 plies are enough for most engineering works. Only in some rigorous situation, airbags will need 7-8 plies to enhance its performance. For example, if people use airbags to lift heavy caisson but their contact area is limited, and then airbags will need higher pressure and more plies to ensure the safety.
Reference for marine airbag selection
There are two industrial standards for marine airbags in China.: one is product standard named "Air bag for ship up to or down to launching way "(CB/T 3795-1996 / CB/T 3795-2009); another is technology standard named "Technological Requirements for ship Upgrading or Launching Relying on Air-bags"(CB/T 3837-1998).The latter offer the basic calculation of marine airbags employed in a marine project.
According to Chinese industrial standards people will know the approximate quantity and specifications of marine airbags needed for their projects then consult the manufacturer to confirm the design. There maybe optional specifications to be selected for a specific marine project and a good manufacturer should know the best choice. The data of marine airbags' blasting pressure will reveal the product's quality level. For top quality marine airbags, such as one 1.5 m diameter and 7 m length Evergreen marine airbag, the blasting pressure is 0.67 Mpa which indicates the safe coefficient is more than 5 considering its 0.12Mpa working pressure.
Full technical service is the qualification of a good company. Although general calculation formula or performance data of marine airbags can be got from most factories but detailed calculations based on mathematic model and experience is more important to the success of marine projects.
In a word
Good selection of marine airbags is vital for the success of marine projects. Get basic knowledge of marine airbags selection then consult with manufacturers can help people complete projects in shortest time.

Eversafe Marine Launch SINOPEC's Biggest Pipelaying Barge with Marine Airbags

On Nov. 26 ,2010 Eversafe Marine successfully launched a pipelaying barge for SINOPEC (China Petroleum and Chemical Corporation) using airbag ship launching technology in Shenli oilfield construction base. That 14,500 tons pipelaying barge named " shengli 902" measures 118 meters in total length and 30.4 meters in molded width. It is SINOPEC's biggest and most advanced pipelaying barge designed to lay maximum 1540 mm diameter pipe at 100 meters deep water .
The hull of this pipelaying barge need to be completed in six months. At that time there was only one 150 meters long concrete ramp available in the construction base. Eversafe technical team was invited by the construction company for the feasibility research of airbag ship launch for the hull. When got positive conclusion, the construction company knew they can take the job.
Eversafe Marine as the launch contractor did lots of preparation work for this launch project. Main disadvantageous conditions for the launch are the shallow water and narrow launch area. With the help from construction company's design department, based on detailed calculation Eversafe technical team designed the launch plan which employ ballast water to adjust the barge's inclination and attached ropes to the stern to turn vessel around.
At 8 AM of Nov. 26, the Sacrifice Sea ceremony was hold on in the construction base. All the people involved in this project gathered to the platform to make a bow to the mother sea. At 8:30 AM the fireworks resounded across the sky and the launch started. When the pulling ropes were released the barge started slowly with the rolling marine airbags and entered into water smoothly. Airbags jumped onto the water surface from the bottom of vessel bow like piquant fishes which aroused excited screams from watching crowd.
Total 67 pieces ship launching airbags were used to launch the barge. All airbags executed good works during the launch. Eversafe Marine (www.eversafe-marine.com) as the subsidiary of Evergreen Maritime, is the first professional global contractor of airbag launch projects and get a very good track record. In addition Eversafe Marine makes his distribution to the airbag ship launching technology by consummating the airbag launch theory.
Marine airbags ship launching can help shipbuilding company to do a better work with less investment. Some people called marine airbags " mobile floating docks" that indicate the flexibility and convenience of this powerful marine tools.

Heavy-lift MPV launching with airbags

On October 25 Eversafe marine engineering company successfully launched a DWT 17000 heavy-lift MPV using ship launching marine airbags for Xinshun shipyard in Zhejiang province.
That double decks MPV measures 143.85 meters in total length,13.5 meters in breadth and 13.5 meters in moulded depth.It is equiped with two 250 tons and one 150 tons cranes. The design speed of MPV reach 16.3 knot. It is the first build ship get GL certification in the local area.
Eversafe Marine Engineering Company has executed 6 ship launching projects for this shipyard in the past two years.Airbag ship launching technology can shorten vessels’ delivery time and save launching slipway’s investment so it is warmly welcomed by most shipyards.
Eversafe technical team collected needed information of vessel ,slipway and water survey data and executed adequate calculation. The results from calculation shows during marine airbags lift and launch stage the safety coefficient is above 6 and 3 times respectively which measure up.
Ship launching airbags are all inspected from airtightness to pressure test before the use. Total 45 pieces ship launching airbags were employed to carry this launch project. At October 24, Eversafe team successfully replaced all keel supporting blocks with inflated marine airbags and adjust the inner pressures of airbags according to the plan. Before the launch the tilted angle of vessel is calibrated to be 1.6 degree to apparent horizon. This angle will determine the movement of launched vessel and the safety of launch so it need repeated calculation and computer simulation confirmation.
At October 25, when the high tide reached expected height shipyard’s dockmaster pulled the trigger of starting gun, then pulling steel ropes were chopped and ship started to move into the water by riding rolling marine airbags.The audiences’ hurrah and Chinese fireworks resound across the sky.
Qingdao Eversafe marine engineering Company is devoted be excellent by over ten years accumulation of executing marine airbags engineering projects. Eversafe can offer clients full service for airbag ship launching from design of slipway to detailed calculation. Never satisfied,always on the road is the motto of Eversafe people.

Airbag ship launching technology blooms

Airbag ship launching technology blooms all around the world by its safety and efficiency nowadays.Even in South America, people involved in ship building can also find this innovative ship launching method in local shipyards,
Eversafe Marine engineering Company strive to serve global clients for marine engineering projects. But for South America, we only once contracted ship launching projects for Chile one country. Last year Eversafe was invited to Surinam shipyards for providing ship launching airbags and launch service. That shipyard is invested by China Timber Resources Group and the biggest one in Caribbean area.
The first constructed cargo ship named “Zhongmu 1” which means China Timber NO. 1 ship . This DWT 1700 ship will mainly be used for transporting wood out of Guyana It took less than one year to complete the construct and was launched on February 26 2009 by Evergreen ship launching marine airbags. It is the first cargo ship build in Surinam so the launch ceremony was held ceremoniously. Surinamese Minister of Forestry, Minister of Transportation, Guyanese Minister of Agriculture, Ambassador Su Ge, Counsellor Cai Shuizeng attended the ceremony.
The launch process is commonplace for Eversafe engineers since the launch weight is only 400 tons and other launch conditions are good. We only need to supervise workers doing job according to the launch plan. The launch looks like a magic show with people hail all the time.
The success launch give Eversafe another contract for the succedent “Zhongmu 2” launch in 2010. The DWT 1800 cargo ship “Zhongmu 2” is the second ship built in PARAMARIBO Surinam invested by China Timber Resources Group. It takes 8 months to complete the build which shorten two months and also the cut the 3,000,000 RMB cost compare with the “Zhongmu 1” build. And cranes are equipped on “Zhongmu 2” to enable goods loading at Surinamese inland ports without heavy equipments.
The ship was launched at May 29. 2010 by ship launching airbags. Chinese Ambassador Yuan cut the ribbon at the launch ceromony, some local officers attended the launch also.
To launch vessels weigh less than 3000 tons with ship launching airbags (also called marine airbags) needs no constructed slipways. The common ground with enough bearing capacity is enough. For big vessel launch by airbags, concrete slipway will be better but the demand for it is much less than traditional slipway. So airbag ship launching can save most time and investment to help clients get advantages in fierce competition.

Jack up launch pictures

New Oil tanker launch by Evergreen ship launching airbags

Eversafe Marine Engineering Company, the subsidiary company of Evergreen Maritime, successfully launched a DWT 11000 Oil tanker with marine airbags for Jiangsu Huanqiu Shipbuilding Company on Sept. 15, 2010.
The vessel named “Future Light” measures 142 meters by total length and 19.5 meters by molded breadth. Its launching weight reaches 4300 tonnes and has 3.6 meters draft at stern. The launching slipway has the variational slope: 12/1000 radian from vessel bow to the watergate, 25/1000 radian beyond watergate until end of slipway. The width of slipway also changes from watergate from 25 meters reduced to 12 meters. The average river water depth of watergate position is 0.8 meters. The distance between oil tanker stern and gateway is more than 30 meters.
The biggest difficulty of this launch projection is the special structure of slipway which may cause the vessel incline to one side or run into dock when it pass by the 12 meter width slipway part. No time to rebuild or do any remediation work to the slipway. The only possible launch solution is using Evergreen airbag launching technology.
Eversafe engineers researched this project for two weeks, from calculation to digital simulation by software. At last we found by adjust the gravity distribution of oil tanker can remedy the inclination moment when vessel pass by the 12 meter width slipway part. To reassure ship owner we also suggest the installation of two Evergreen pneumatic fenders on the dock. The discussion meeting with shipyard and ship owner is cheerful, all people here think the launch proposal is the best and safe way that we can do at that time.
According the scheme the oil tanker will be moved toward river for 20 meters by marine airbags then laid on marine airbags until next day morning when the water reaches appropriate depth.
At Sept. 14, Eversafe team completed the move forward work using 42 pieces YT-6 Evergreen marine airbags that have 1.5 meters diameters and 18 meters length. The next day 8 am people begin to adjust the air pressures of marine airbags to make vessel inclined with right angle. At 9 am the launch water area is blocked and two tugboats are ready. With the shot of starting gun the pulling steel ropes are cut down and oil tanker enter into water straight forwards with the rolling marine airbags and anchor at the appointed place after total refloatation. Hails from people and fireworks which resound across the sky accompany the magic launch process. There is no splash of water, no stern or bow fall off, no decline to one side phenomena happen during the launch.
The success of this marine airbag ship launch project verifies Evergreen airbag launch theory again. Without accurate calculation people can’t complete the launch on defect slipway so smoothly. For shipyard and ship owner they are glad to deliver or get oil tanker on time without extra cost of slipway repair or employ launch barge.
Evergreen airbag ship launch technology is invented initially for emergency launch such as during war or nature calamity period people can launch vessel without constructed slipway. Nowadays this ship launch technology is developed into a very flexible and effective solution and sometimes it becomes an essential for launch under imperfect condition.