Salvage Aground cargo ship with marine airbags

Jialing river, A tributary of the Yangtze River is the important sea route of Sichuan province. The Jialing River's most notable characteristic is its rapid flood and drop. One cargo vessel in Jialing river loaded with 1500 tonnes beans run aground near Jiangbei wharf after a rapid drop down of water level. Half of vessel rested on a bank slope , its bow was 3 meters higher from the ground. The distance of aground vessel to the nearby bridge pier is less than 100 meters.

Considering the possible collision of vessel with bridge pier by fluctuant water, people must salvage the vessel as soon as possible. Eversafe engineers were called to the site urgently. After checking vessel bottom, Eversafe engineers presented the salvage plan: using fours pieces marine bags to lift vessel up from bank , then vessel can move into water with rolling airbags by its gravity force. This plan was the most convenient and economical method to relaunch the vessel at that time. After a 30 minutes discussion of ship owner with our engineers, Eversafe Marine got awarded the contract. During the period of waiting for airbags arrival, people began to discharge cargos on vessel. Fours pieces marine airbags was trucked to the site in the next day. The first air bag was inserted to lift up bow slightly, then left bags were installed one by one. When vessel bottom was fully lifted up from slope, Eversafe engineer slowly lifted up vessel’s bow to start vessel movement. About 30 minutes, the vessel entered into water totally. It is a simple but ingenious salvage operation that indicates airbags salvage advantages. Marine airbags are easy to transport and can lift up thousands tonnes vessel only need a solid support ground. Marine airbags can refloat vessels underwater with their buoyancy. So marine airbags enable companies to do salvage jobs with small investment. Souce from: Eversafe Marine

Docking Conversion ship with marine airbags

Eversafe Marine contracted a 3600 tonnes conversion ship docking project recently. That ship with 8.2 m molded depth is 122 m long and 32 m wide. The hauling out project was carried out with 22 pieces marine airbags and two 20 tonnes winches on Yangtse river side.

Docking ship with air bags is a good choice for remote area where lack of docking slipway or temporary docking. Compressed natural ground can meet the docking demand of small size vessel. To enhance ground bearing capacity for big vessel docking with marine airbags, steel plates are found to be convenient and useful.

Eversafe cargo ship airbag launching projects

On 7th March 2012,the DWT 20800 cargo ship "Dong Hong Hang 3" was launched with Eversafe airbags in Zhejiang Donghong shipyard.

Two days later,another DWT52000 cargo ship was successfully launched by Eversafe airbag launching team. The cargo ship named "Yong Xing NO.5" with unattended machinery space is classified by CCS (China Classification Society). It measures by 195 m total length ,32.3 m moulded breadth and 17.3 m depth.

Those airbag launching projects go smoothly since the concrete slipway and water level are both satisfying. By calculation Eversafe Marine optimized the air bags space and pressures to control the launch speed and ensure the launch safety when vessel bow refloats.It took two days to jack up vessels with airbags and remove support blocks, only 90 seconds to launch the vessel into water.

On 8th April, in the same shipyard the third DWT 13000 cargo ship was launched by Eversafe Marine.The ship named" Dong hong 37" with 120 m total length,22 m moulded breadth and 11m depth. It is classified by BV.

Eversafe Marine is the total contractor for above launching projects, providing design, marine air bags and launching team. Eversafe Marine is devoted to airbag engineering, from vessel launching to heavy lifting and transport.Safety and high efficiency is company's goal.Eversafe Marine now has the ability to perform three global projects at the same time.

News from : Eversafe Marine

Comparison of marine airbag and SPMT for heavy load out

Marine airbags are often called ship launching airbags that indicates they are most used for launching ship into water. Inspired by ship launching, people developed many applications of marine airbags in different fields, the most remarkable one is heavy lifting and moving with marine airbags.
SPMT stands for self-propelled modular transporter, a platform vehicle with a large array of wheels; it is equipped with Power Pack Unit which provides the propulsion.
Obviously marine airbags are not as famous as SPMTs in heavy lifting and transport fields. The main reason is that marine airbag is not a high developed industry product yet; its ISO standard was issued only at 2011 years. Due to special manufacture technology marine airbags can only be made in China which also limited its worldwide development.
Marine airbags heavy lifting and load out has similarity with SPMTs but more difference. A comparison may help people to know their individual characters.

Heavy Lifting

Lifting Capacity
The SPMTs consist of four-axle units or six-axle units, the maximum allowable axleline payload is 30 tons per line. Then we can know:



Marine airbag’s lifting performance is decided by its working height and inner pressure.

Airbag specification Load Lifting height Airbag pressure
1.0 ×15 m 471 tons 0.5 m 4 bar
1.5 ×15 m 235 tons 1.0 m 2 bar
2.0 ×15 m 420 tons 1.0 m 1.8 bar

Provided there is a caisson with follow dimension needs to be lifted.

Length（m） Width（m） Height（m） Weight（t）
20.45 13.45 17.3 2357

To lift this caisson at 0.5 m high from ground people may choose 6 pieces airbags (1.0×15 m). The total 6 pieces airbags’ lifting capacity is 422×6=2533 tons. Air bags can be positioned with 4 m space.
To lift this caisson with SPMTs, people will need 2357/180=13 units 6 line modules but the structure dimension decides maximum 12 units modules can be deployed. Then SPMTs is not suit for this caisson lifting and moving.

Article from : Marine airbags VS. SPMTs

Eversafe project of concrete structure shift with air bags

Tieshan Port Industrial Park is located in Guangxi Zhuang Autonomous Region, China. The Park is one of the three important industrial zones for the Beibu Gulf Development, which was approved by China’s Central Government.
The construction project consisted of two phases: the NO.1-2 berth construction have already been finished and NO.3-4 berths construction work started from August 2010.
In plan total 40 Caissons will be installed for NO.3-4 berths construction. Eversafe Marine was engaged by the Administration for the Beibu Gulf to carry out caisson transportation works, from fabrication site to submersible barge with heavy lifting marine airbags. Caisson transportation with marine air bags is a new technology which doesn’t need rails and trolleys and can transport concrete structure on compacted ground. So it enables fabricating caissons on temporary site which can be located near shipping position. Using balloons to transport caissons to submersible barge then launch it can save more than 40 percent investment comparing with trolley transportation method,not mention the time saving.
The first caisson measures 24 meters by length, 16.4 meters by width and 20.75 meters by height. Its weight reaches 3050 tons. To move caissons from construction site to shipping out position , Eversafe team made the masterly plan which consists of three steps: lifting first ,length ways move then transverse move. Total four winches were employed to control caisson movement: two winches from submersible barge to pull caisson move forward and other two winches were used to stop caisson.
Total 8 pieces heavy lifting air bags with 1 m diameter and 16 meters length were used to lift the caisson. Each air bag carry about 380 tons with 0.25 Mpa pressure. To roll caisson out 24 pieces 8 meters long air bags were arranged in two rows and kept in 40 cm height to ensure caisson movement stability. It took us about 3 hours to transport the first caisson to ship out position.
When using air bags to move caissons aboard submersible barge, the barge need not to sit on seabed. Often people use steel plates to connect bank and barge deck to roll caisson on to board. Submersible barge can rise or sink by adjusting ballast water to adopt coming caisson. And in flood tide the barge operation will be easier.

Wuzhou Heavy industry launched DWT36000 cargo ship

On 24th November Wuzhou Heavy industry launched a DWT36000 cargo ship with Eversafe airbag launching service. This cargo ship measures 190 meters by total length and 28.3 meters by moulded breadth. It is named “ Meishan gang 57” by owner Zhejiang Hongchen Shipping Company which is a private owned transportation company.
Lianyungang Wuzhou Shipbuilding Heavy Industry Co., Ltd. was founded in May 2007, is located in Jiangsu Guanyun County town of Lianyungang which is adjacent to the Guanhe River estuary. Currently the company covers an area of 880,000 square meters, has 1.1 kilometers of coastline. Has built five berths below 20,000 tons, eight berths between 30,000-50,000 tons, one berth of 80,000 tons. The shipyard equipped with 32 gantry cranes which include 200 tons and 100 tons.
This river is in low water period so launching water is 2 meters lower than normal level. To conquer this big difficulty Eversafe marine performed detailed calculations to find good solutions of airbag launching. By discussing with shipyard Eversafe Marine decided a dredging plan to ensure the launching.
On 22th November Eversafe launching team arrived at shipyard to prepare the launch. After two days working, we finished the air bag ship lifting and blocks removal works. In 5 PM of 24th the final launching started. After pulling ropes were cut off the ship started to move slowly. With rolling airbags it entered into water smoothly and steadily until floated totally. The whole launch took 90 seconds.
One client from South American shipyard was invited for this airbag launching view. The client was interested in changing slipway launching to air bag launching in near future.
In November Eversafe successfully launched 4 new built vessels which include two cargo ships and two OSV. In the winter of shipbuilding industry around the world Chinese shipbuilding market still hold a strong increasing posture that is food for thought.

LPG Cargo Tank Air bags lifting Project-Eversafe Marine

On May 29 2011 Eversafe Marine Engineering Company successfully completed a LPG Cargo Tank lifting Project with heavy lifting airbags in COSCO shipyard. That VLGC cargo tank weighs 1600 tons with 40 m length , 30 m width and 20 m height.
During the Japanese Tsunami in March 2011 that VLGC hold space was damaged and water ingress of approximately 7m above the inner bottom caused the cargo tank to float freely. As a consequence the 64 pieces wooden liners from the lower tank supports have floated out and the tank was sitting directly on the steel plates. The cargo tank had to be lifted in order to fit back the wooden liners.
Airbag lifting would take and distribute the load evenly over the inner bottom and tank bottom. Contrary to hydraulic jacks and floating crane no additional reinforcements of the structure was necessary.
Also airbag lifting can be precisely controlled which is also one of selection reasons. The tank in hold place has very limited space from the top and sides: the space on top of tank is limited to 12 cm and in four sides only 60 cm space is available. To put back wooden liners tank need to be lifted up11 cm from the support blocks and lowered down one centimeter by one centimeter. So the lifting and descent must be totally controlled.
A pre-inspection was carried out by Eversafe Marine in order to determine the space available for the airbags. One access hole was cut in the portside of the hold space to allow smooth transport of airbags.
To settle airbags in proper positions the limited space made troubles for us. Since no heavy instruments can be installed for the airbag hauling in the hold space people have to use chain blocks as main transportation tool. The height from hold space to tank bottom is 64 cm people even can not squat when they work under the tank. It is a hard work to settle total airbags in their positions in two days.
In the morning of May 29 2011 the airbag tank lifting work started. Eversafe technicians carefully controlled the inflation process to ensure upright lifting up. In our hour the tank was lifted 11 cm up from the support blocks. In the afternoon when all wooden liners were placed in proper positions the tank was lowered down one centimeter by one centimeter until liners fit into frames. Tank lifting/lowering was completed on 29 May, 17:00 local time. All 64 pieces of wooden liners were placed back successfully.

DWT 47,000 cargo ship launching with marine airbags

Evergreen Maritime is the professional manufacturer of ship launching airbags and dock fenders. Also his Eversafe marine engineering company is well known as the leading engineering company engaged in ship launching/landing and heavy lifting projects.
Recently Eversafe Marine successfully launched a DWT47000 cargo ship with marine airbags in Nanjin Jinda shipyard. That ship named “ tai he da” weights 9000 tons, measured by 190 m length, 32 m moulded width and 16 m depth.
The launch slipway is a concrete ramp with 1/80 slope angle. From end of slipway to the Yangtse river there is a 60 m natural ground paved with gravel. Yangtse river is one of the most busy channel so our launch is strictly limited for the launch time and launch area by local Maritime Safety Administration.
The elevation of launching ramp end is 2 m and stern draft is 1.7 m so stern will not be refloated when it is launched at 120 m distance. To remedy the practical disadvantage Eversafe team performed the detailed calculation of using ballast water to adjust the vessel trim angle during launch. At last 2000 tons ballast water was added into the bow cabin.
In the morning of May 21 our launch team begun to prepare all necessary work for the 40 m forward move and successional launch that must be completed within there hours. At 9 am the vessel transportation work started and got finished in one hour. According the plan this vessel will be launched at 12 am when the water reaches highest level in the day. Because of some emergency reason the local Maritime Safety Administration demanded the launch to be carried out at 10:30 am. So we got only 30 minutes to prepare the launch.
Water level in the launch area is 100 cm less than plan so marine airbags and ramp will bear more pressures than expected figures. People reinforced the conjunction of ramp with steel plates temporarily and adjusted pressures of airbags at stern. At 10:30 as soon as adjustment work finished pulling ropes from winches were chopped and the launch started. The vessel got total floatation at 300 m and stopped at 460 m distance.
After the launch people found there was a gap at launch ramp conjunction position. Provided without the temporary reinforcement the part of ramp may collapsed during the launch.
It is a very urgent launch project. Eversafe team depends on the scientific calculation and profound experience overcomes all practical disadvantages and did a great job. It is the fourth vessels launched by our company in this month . Airbag ship launching is proved to be successful and flexible in deficient conditions.

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.

Landing craft launch with Evergreen marine airbags

Strategic Marine has delivered a 48.5 metre landing craft which will service the Australian offshore oil and gas industry and major projects including the multi-billion Gorgon Project.
The vessel, built for local Western Australian marine operations company Bhagwan Marine, will be used in Western Australian’s north-west hydrocarbon province and has been designed by International Maritime Consultants, to accommodate for low incline beach landings.
The craft’s design features a low angle bow to enable heavy equipment to be driven over the ramp door and with a 12.8 metre beam, the vessel can accommodate up to ten 20-foot containers with a maximum payload of 400 tonnes.
Although a multi-cargo vessel, it will be primarily used to transfer building and construction equipment in the areas around Dampier, Onslow and Barrow Island while an added advantage is its economical fuel consumption of about 150 litres per hour at 10 knots cruising speed.
The vessel, named “Bhagwan Shaker” after its sister vessel “Bhagwan Mover”, was built at Strategic Marine’s largest shipyard at Vung Tau .
Strategic Marine will also build a second 40 metre crew boat on speculation after the first 40 metre crew boat the company built on speculation was purchased by Tiong Woon.
Like the first 40 metre vessel, due for delivery around October 2010, the second 40 metre vessel will incorporate a central deck house with seating for 50 rig crew and will reach speeds of 25 knots.
It will be a sister ship to 14 similar vessels delivered to a number of clients over the past five years.
Strategic Marine’s Vietnamese yard successfully launched the first 143 m DSV using Evergreen airbag ship launching technology at April 2010. Then this innovative ship launch solution is found to be safe,flexible and effective. So the landing craft is decided to launch with marine airbags also.
The company is currently contracted for more than 25 vessels at its yards in Australia, Vietnam and Mexico and Singapore, equating to approximately $100 million (AUD) worth of orders.

Why Foam-filled Fenders?

Fenders are an essential part of any dock or harbor facility. Docking a ship is an imprecise matter, and fenders must be in place to keep ships from being damaged by bumping, scraping or crashing into docks. By the same token, the docks themselves must be protected from damage by ships. Fenders also come into play to prevent damage from ships coming into contact with each other. Every vessel from a pleasure craft to a fishing boat to a supertanker needs fenders; every structure from a dock to a bridge to an oil rig does, as well.
Historically, fenders were woven together from rope, in a variety of knots and patterns still known and used today by many traditionalists. They would typically be covered with a layer of old tires
as a buffer, then used as a fenderboard along a dock piling. Like everything else, fenders have been improved over the years.
For years, the inflatable Yokohama fender was the state-of-the-art fendering system. Yokohama fenders, however, require air pressure and safety valves that need to be maintained. Inflatable fenders also have a “recoil” that will cause ships to “bounce” in the other direction after contact. Thousands of inflatable Yokohama fenders are still in use worldwide, but the next logical progression in fender and mooring technology is the foam-filled fender. Constructed with a tough outer skin and heat-laminated layers of foam at their core, foam-filled fenders offer the following advantages:
• Softer berthing. Unlike the “bounce” of inflatable Yokohama fenders, a foam-filled fender rebounds more slowly, rather than jolting the ship and its passengers as it buckles and rebounds.
• All tide mooring. Foam-filled fenders, by design, make mooring easier regardless of tidal phase or conditions.
• Hull conforming. The design of the foam core in a foam-filled fender gives great resilience and the ability to conform to a vessel’s contours. The result is a more even distribution of energies over a greater area, and much lower hull pressures.
• Unsinkable. Like a fishing bobber, the foam core of a foam-filled fender makes it impossible to sink.
• Durable. Foam-filled fenders are available in different rubber compounds like neoprene, EPDM, butyl and polyurethane. The result is a product that is resistant to saltwater, ultraviolet rays, ozone aging, dry rot and extremes of temperature and weather, making it suitable for use in any environment worldwide.

"Ocean bravis " Launch with Evergreen Marine Airbags

Eversafe engineering team successfully launched a DWT 8,800 tons cargo vessel named "Ocean bravis "with 30 pcs Evergreen marine airbags on the July 13, 2010. It is the third vessels successfully launched by Eversafe team in July.
"Ocean bravis " is constructed for ARROZ group with 108m LOA,26m molded width. It is initially proposed to be launched on traditional slipway by end-on launching method. For some untold reason the shipyard decided to launch this vessel with marine airbags.
Evergreen maritime company is pioneer in maritime industry for providing innovative ship launch solution and top quality marine equipments which include marine airbags and pneumatic fenders etc.
Evergreen was honored to be invited to do the consulting work for “Ocean bravis” launch slipway alteration and launch contractor. According to the calculation and practical limitation of investment Evergreen provided customer a cost-effective solution of the slipway alteration which was agreed by the local authoritative department in a week.
For this launch project, the launch weight is only 3000 tons but the angle of slipway is much bigger than ideal condition so more calculations were performed to ensure the safety of launch.
Two SWL 25 tons winches and 30 pieces Evergreen marine airbags are employed to carry out this launch. Marine airbags are inflated from the bow to stern to lift up vessel from wooden blocks first. With the pull protection of winches marine airbags then be inflated or deflated again to adjust their working heights. After marine airbags are ready, people release the winches to let vessel go down slowly into water. When the stern is immersed at 1.5 meter depth, ropes that pulling the vessel are chopped to release ship go freely. Then vessel enters into water smoothly.
Marine airbag ship launching is developed into a flexible and easy technology with accumulated research and practical experience. It can overcome the limitations of traditional launch methods and it always can be found reliable and controllable.

How to select marine airbags for your launch project

Marine airbags will cause people most interest once people have the experience of watching marine airbag ship launching. It looks like the magic show that big vessel run into water by riding rolling pneumatic rollers. In China most new built vessels whose DWT below 60,000 are launched with the “flexible ship launching technology” which definitely differ from traditional launch methods. Marine airbag ship launching technology gets the least limitation of landscape so it can save people most money and time.
The first difficulty for people to apply marine airbag for ship launching is how to decide if the vessel can be launched by airbags and select marine airbags. Most Chinese manufacturers will only tell you to do what but not why to do that when you consult with them for your launch project. In fact some manufacturers don’t know much of the marine airbag ship launching technology even they make marine airbags. Some real jokes: a manufacturer sold many marine airbags to a Turkish client and when people prepared launch they found no place to fit all marine airbags into bottom of vessel. Another joke sounds like that a manufactures sold 20 pieces marine airbags with 2.5 meters diameter to Malaysian shipyard to launch a 60 meters tugboat with only 700 tons. To avoid be fooled by some unprincipled manufacturers, there are some lies that people must know.
Lie One: Bigger diameter means better performance
People may be fooled by numeral tricks when they read performance data of marine airbags issued from manufacturers. People are leaded to believe that the bigger diameters of marine airbags have the better performance. In fact the performance of marine airbags is decided by the burst pressure which means the maximum pressure of airbags can bear. It is easy to understand that for the same material made bigger volume container will has less burst pressure. From the test data people can prove this prediction comes from common sense: the bursting pressure of marine airbags with 1.5 and 2.5 meters diameter is 0.67 Mpa and 0.23 Mpa respectively. When a 1.5 m diameter marine airbags and another 2.5 m diameter one are inflated to the same pressure, it is definitely the bigger diameter one will rise up heavier objects because of its bigger contact surface. But the bigger diameter one gets some problems that its pressure can not exceeds 0.23 Mpa and it will lift up vessel higher which will cause the extra demand of launch water level also its bigger contact surface with ground will need more slip force for vessel to start movement. In a word, marine airbags with the diameters exceed 2 meter are suit for some special lifting use not for vessel launching. During ship launching process marine airbags will be compressed and their inner pressure will rise to be nearly 2-3 times of initial pressure so marine airbags must have 3 time safety coefficient. Most 2-2.5 meters marine airbags can not get 2 times safety coefficient.
Lie Two: More plies means better safety
Some clients would like to believe marine airbags with more plies will ensure better safety. It is true that the 7 pliers marine airbags’ maximum pressure is higher than 6 pliers one. But good arrangement and maintenance will ensure much more safety of your marine airbags. The thickness and maximum pressure will increase no more than 8% when marine airbag’s plies increase one. So in most cases marine airbags with more plies can not offer a visible enhanced safety but the psychological effect. In fact the professional manufacturer has optimized the plies and structure of marine airbags. Most popular Evergreen marine airbags are 6 pliers. They have the best cost performance and more than 5 times safety coefficient which is enough for most marine projects.
Lie Three: More marine airbags employed for project means better safety
Like people always say going too far is as bad as not going far enough, too many marine airbags for the launch project may cause danger. There is a minimum space required for marine airbags arrangement. If marine airbags are placed too closer, they may huddle together and can not roll forward when they are compressed more during the launching process. Please note marine airbags will be compressed differently in the different launching period. Even marine airbags are not adjoining before the launch they can still huddle together in launching period.
After see through lies of marine airbags people may ask then how can we know if our vessel can be launched by marine airbags? The answer is simple: four conditions should be satisfied.
1. Vessel is prepared to be end launching
2. DWT below 60,000 tonnes
3. Launching channel’s width no less than 1.5 times of vessel’s length
4. For some special ship launching such as V-shape vessel additional brackets may be needed
To select suitable marine airbags for your marine projects you may refer the following.
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. There maybe optional specifications to be selected for a specific marine project and a good manufacturer should know the best choice. Suggestions from Qingdao Evergreen Maritime Company: for ship launching, the airbag’s diameter and length should not exceed 2.0 meter and 18 meter respectively; for caisson conveying, the 1.0 meter diameter is suitable for most projects.
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. Never forget to ask for the maximum pressure from manufacturers if you want to buy marine airbags from them.
Full technical service is the qualification of a good company. Although general calculation formula or performance data of marine airbag 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 marine airbags is a good powerful tool for lots of marine projects but people need to know some principles before using it.

DWT35,000 cargo ship launched by Evergreen marine airbags

Eversfae engineering company successfully launched a DWT35,000 cargo ship with 48 pieces Evergreen marine airbags on June 15 2010.This vessel named “Five continents 05” was built by Five Continents Shipbuilding Company located in Jiangsu province.
Marine airbag ship launching projects are commonplace but to launch a big vessel is still an exciting work. “ Five continents 05” measures 178 meters long and 28 meters width, its launching weight is 9,000 tons. This vessel is built on a 0.01 radian concrete slipway which has abrupt down end, a very dangerous structure for marine airbag ship launching. The drafts of stern and bow are 4.2 meters and 2.4 meters respectively.
The difficulties of this launching project are as follows: bad slipway, heavy weight, long length. A vessel will not start to move relying on gravity’s slipping down component of gravity force if its inclined angle is 0.01 radian. Long vessel will need careful arrangement of marine airbags to ensure the safety of hull structure.
After negotiating with shipyard, Eversafe engineers supervised the modification of slipway end structure and got two tugboats to handle with any emergency during the launching. At June 14 Evergreen team began to inflate well arranged marine airbags to raise vessel and remove wooden blocks. Firstly, eight pieces marine airbags under the bow were inflated to be 0.20 MPa pressure then twenty pieces marine airbags were inflated to be 0.18 Mpa and left airbags were inflated to be 0.16 Mpa. So the vessel was lifted by total 48 pieces marine airbags easily.
As the high tide time of June 15 is at 9 AM the launching time is set at 8:45. In the morning of Jun 15, Eversafe team began to adjust pressures of 20 pieces marine airbags under stern to be 0.12 Mpa and 28 pieces marine airbags under bow to be 0.2 Mpa. Then the vessel got an approximate 0.013 radian inclined angle. At 8:40 am, people began to chop up the steel ropes which were attached to winches to pull ship to avoid unexpected slip. As soon as the ropes broke down vessel started to move into water by riding rolling marine airbags smoothly. It took 2 minutes from the vessel’s movement start to fully float.
From this ship launching project people can easily find irrefutable evidence of Evergreen marine airbags’ excellent quality. During the vessel lifting up period, pressures of eight pieces marine airbags reach 0.2 Mpa and holding these pressures more than 10 hours. It means each marine airbag bears more than 300 tons weight and no air leakage occurs in 10 hours.
Evergreen Maritime is devoted to be excellence. Up to date technology and new material are constantly applied to manufacture of marine airbags to assure Evergreen marine airbags can always satisfy customers’ increasing demands.