Sunday, July 22, 2012

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

Wednesday, June 27, 2012

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.

Sunday, April 15, 2012

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