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Boat launching bladders are a very popular way to launch boats, especially in Asia, where many shipyards purchase marine bladders for launching. This method of launching the water greatly reduces the cost of preliminary preparation and ensures safety. It is suitable for launching, repairing and towing all types of ships.
Many customers don’t know how to calculate the number of marine launch air bags. They might think “my boat is 100 meters long, why do I need so many marine air bags?” Does it make me spend more money? In fact, the calculation of the number of marine airbags is a very technical operation. There are many force data that need to be considered in the calculation process, and the process is quite complicated. Today, Nanhai will share with you the calculation method for selecting marine launching airbags. Through this calculation guide, I hope you can understand how Nanhai’s technicians provide suggestions for marine launching airbag solutions, and check whether the solution given to you by the other party is reasonable after you get the quotation. Avoid encountering random quotes from unreliable small companies.
1.How does the ship launching air bag work?
Before we start looking at the options for boat launching air bags, let’s first take a look at how these boat air bags are launched into the water.
Ship launching project steps:
1.1 Remove obstacles that block the rolling of the marine airbag during the launch of the ship and obstacles under the ship. Make sure the slide is smooth and clean. This step will not be hindered by any object during the ship launching process to ensure the safety of the ship launching process. There may be sharp, hard objects such as large rocks or shells washed up on the shore. They can also puncture boat launch bladders, so it’s important to clean them and adjust the slide rails.
1.2 Connect strong components such as the bow and mooring posts to the movable pulley block of the traction winch to tow the ship.
1.3 According to the technician’s operation plan, place the marine launching air bag under the bottom of the ship and inflate it to the specified air pressure. When the bottom of the ship is higher than the bridge piers and the weight of the hull is all pressed on the marine launching airbag, remove all the bridge piers and deflate the marine airbag appropriately to balance the force.
1.4 All work-related crew members are ready to board the ship.
1.5 Consider the width of the water area, select a suitable launching location, loosen the wire rope and move the ship near the water area. Cut the wire rope or release the shackle when appropriate, and the ship will automatically enter the water area. Launch into the water with the help of sliding power.
1.6 After the hull is completely submerged in the water, drag the ship to the dock, measure the draft at the fore and aft, and check whether there are leaks in each cabin.
1.7 Retract all marine launching airbags and record launching information.
2.Select the calculation method for ship launching airbags
After understanding the general ship launching process, let’s take a look at how Nanhai’s technical engineers calculate the number of marine airbags. When our technicians receive your quotation request, they need to know the following information: ship type, length, ship width, ship deadweight, angle between the ship launching ramp and the ground material, tide table of the launching sea area, water depth, and flow rate information
For concrete ramps, the friction coefficient of the marine airbag against the ramp is 0.01-0.0125. For compacted natural foundations, this factor is 0.0125-0.02.
After understanding the above information, the technician will calculate the number of marine airbags required to launch your ship according to the following calculation formula:
In the formula, N is the required number of marine launching airbags, K1 is the airbag coefficient, Q is the weight of the ship, g is the acceleration of gravity, Cb is the square coefficient of the ship, R is the maximum carrying capacity of the airbag per meter, and Ld is the contact length between the airbag and the bottom of the ship. (m).
All calculation technicians will repeat calculations more than three times to ensure the accuracy of the values. The customer will then make a quotation based on the quantity of marine airbags required. If you want to know the number of marine launching airbags required for your ship launching project, you can call Nanhai and we can select the model for you free of charge.
With this formula, you can also do your own calculations after accepting the selection recommendation to see whether the number of marine airbags recommended by the other party is reasonable. However, it should be noted that when the ship is moving, 2 to 4 reserve marine airbags should be prepared. This is very important and our company has calculated the number of marine airbags for you.