Technical discussion of air bag launching, heavy lifting and vessel haul out

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Technical Discussion

1. What is advantages of airbag ship launching and what kind of shipyard will need this technology?

The most prominent character of airbag ship launching is its low demand of launching ramp.
Various ramp angle
The basic principle of Airbag ship launching technology is rolling out vessels by airbags just
like ancient people use round logs to transport heavies. Comparing with traditional slide launching, the rolling friction of airbag ship launching is much smaller which indicates airbag launching need smaller launch slope.
Generally end-on and side slipway launching need 1/22 and 1/8 slope angles. Airbag  launching
slope can range from zero to 1/20 which enable people to build launch ramp according to existed slope.
Low demand of ramp bearing capacity
Airbags have bigger contact area with vessel bottom comparing with launching sledges (blocks), so
the launch ground bear less pressure during the launching. That is why airbag ship launching has less bearing capacity demand of launch ramp.
Low demand of ramp planeness
Airbags are flexible they can pass by uneven local of launch ramp safely. So less planeness demand
of launch ramp is another advantages of airbag ship launching.In the practical launching projects unpaved natural ramps have also be used. Anyway that natural ramps should have enough bearing capacity and relative flat ground. For small size vessel ( DWT below 5000) the demand of airbag launch ramp is not strict. But to launch bigger ones people will surely need a good designed concrete launch ramp.
Less underwater construction
Standard designed airbag launch ramp will have underwater part which is much shorter than
traditional launch slipway. So investment can be saved.
No maintenance of ramp
Airbag launch ramp need no maintenance which is also great advantages comparing with wooden
slipways or iron launch railways.

Other features
Besides the low demand of launch ramp, airbag ship launching is also a kind of green technology which says it has no pollution to environment. Sliding launching often need grease but airbag launching only need air.
Airbag ship launching technology enable people to build ship at any place. When vessel is finished
people can move it by airbags to launch ramp then release it to water. This character can rescue people when they are suffered from insufficient slipways.

2. Can marine airbags be reused? How many times it can be used?
Yes.Marine airbags surely can be used and for many times. Proper usage and good maintenance can
prolong airbag’s lifespan. Generally speaking marine airbag can has 5-8 years life.

3. How can marine airbags make vessel takes a turn when they are used to move vessel?
Airbags have been used for heavy transportation for many years. In most applications the
transported heavy often need to be turned around during forward move process.
The principle is same like vehicle takes a turn . When a 4-Wheeler/Car takes a turn, to enable it
go through it smoothly, its ‘outer’ wheels need to turn faster than the ‘inner’ ones.
When people want to turn the vessel with airbags they will place the front airbags to be inclined.

The front 3 pieces airbags are placed inclined, when they move forward they move like to go around a circle center. So the A\B\C three points’ speed is bigger than D\E\F. Since behind airbags are perpendicular to the vessel center line, the H and I points have same speed. So when vessel goes forward its front will turn right.
That is the basic principle of airbags turn vessel. In the practical operation people will pull forward or pull back vessel for some times to make an accurate turn.
That is also why we try to make airbags to be perpendicular to launching direction as accurate as we can when we want to launch vessel in line.

4. What is the maximum pressure of marine airbags?
Here we understand maximum pressure means maximum safe working pressure. The structure layers and diameter effect airbag’s maximum working pressure in fact. With more layers airbag can have higher working pressure, bigger diameter the lower pressure.
We have tested every type airbag’s bursting pressure so we know the pressure limit. Just to prevent from cribbing we won’t publish the data in public. Ask us in private you will get what you want.