4 Types of Ship Launching Methods
Launching of ships is one of the most important procedures of the entire ship construction process. The ship launching slipway, a structure consisting of a sloping way down to the water from the shipyard, is an essential aspect of the ship launching procedure and has been extensively used for launching newly made or repaired ships.
Last few years have seen a number of developments in the field of ship launching systems for improving the safety and stability of the ship in the water.
Different types of Ship launching methods
Traditionally, ship launching in the water is done using four main types of methods. These methods are:
- Gravitational type launching
- Floating-out type launching
- Mechanical Type launching
- Airbag launching
1. Gravitational type launching : The gravitational type launching system is further divided into three main types, which are:
- Longitudinal Oiled Slideway Launching
- Longitudinal Steel – Roller Slideway Launching
- Side Oiled Slideway Launching
Longitudinal Oiled Slideway Launching
The longitudinal oiled slideway launching is one of the oldest forms of launching systems. Using this system, the ship slides on a 
The main advantage of this method is that it uses simple equipment and can be used for vessels with different tonnage and types. However, the coating of oil which is used to slide the ship smoothly can pollute the water. There is also danger of huge pressure on the front part of the ship during the launch.
Longitudinal Steel – Roller Slideway Launching
In this type of ship launching method steel rollers are used instead of oil to reduce friction during sliding. This method uses high-intensity steel rollers, security devices, and steel board for the launching. The steel plate on the wooden slide helps in the sliding process and the slide rails help them to protect from steel balls.
Net bags are used at the end of the slide to collect the steel balls so that they can be used again. This method is most effective and easy to start. However, the initial installation charges are high.
Side Oiled Slideway Launching
In the first type, the slideway extends into the water and the ship slides into the water using the slideway. In the second method the slideway doesn’t go until the water and the ship along with the frame slides into the water. The ship then becomes steady based on its own buoyancy and stability factors. Such launching requires the ship to have great stability and strength.
2. Floating- Out Type Launching The floating out type launching is carrying out for ships which are built in dry-docks and are launched by filling the dock with water. (Technically this is not a ship launching procedure)
3. Mechanical Type Launching
The mechanical type ship launching system can be divided into following types:
- Longitudinal mechanized slideway launching
- Two points longitudinal mechanized chute launching
- Wedge-shaped mechanized vehicles launching
- Slope change transverse area mechanized vertical chute launching
- High-low track slide mechanization launching
- Lifting ship equipment
All the above mentioned system requires a mechanical feature to launch a ship. The construction and maintenance expenditure is high, whereas the mobility and controlling factors of the systems are not up-to-the-mark. All these methods are mainly used for smaller size vessels and cannot be used for large, high tonnage ships.
4. Air bags Launching
Launching ships using air bags is an innovative and safe technique to launch ships in water. These airbags are usually cylindrical in shape with hemispherical heads at both ends. They are made of reinforced rubber layers and have high load capacity. This method can easily be used in all types and sizes of vessels.
Do you think we have missed any important ship launching method? Let us know in the comments below.
References- Evergreen
Image credits – flickr, murdoconline.net, worldmaritimenews, Evergreen
You may also like to read – How Are Ships Named – Naming and Launching Ceremony
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Can anyone tell me what a “Trigger of Port Fore Dog Shore” is.? This item ( resembling a large block of wood with a rope through a central hole)
I suggest it is the “king-pin” which ,when removed, releases the supporting timbers holding a vessel upright in the construction dock and allows the vessel to slide down the slipway to actual launching. I also assume that there would be a similar “trigger block” on the Starboard side of the ship which would be removed simultaneously.
ANY COMMENTS PLEASE???
Great post! I think that side launching is one of the most popular method for most small to medium vessels.
It’s great to also note that ship launching using marine airbags is claimed to be more eco-friendly than oiled slideway launching and more cost effective than the other options. I like how this blog post highlights the pros & cons of airbag launching in an infographic: https://max-groups.com/ship-launching-airbags-best-ship-launching-method/ . You might wanna check it out.
I remember soft soap being applied to the ways before oil was used.
does the airbag method also work on gravity? except that it uses airbags instead of slideways/rollers?
Has anyone ever had any legal ramifications due to damage inflicted on nearby property owners caused by a wave resulting from the launching of a vessel
dear sir
i would like to cooperate for marine writing and also regarding shaft alignment i would like to asking help for some points.
highly appreciated if you be kind and help
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what are the basics of troubleshooting of main engine machinary?
Item 2, dock launching have the graving dock launch which is not strictly a launch more a floating out. But we also have the roll out into the FDD and the FDD moved then submerge to launch the vessel. This is a good use when the water depth close to the building area is too shallow, the vessel being built on the quayside, is then jacked up and moved into the FDD, the FDD is moved to deeper waters and the vessel launched and brought back to the outfitting berths for final fitting out.
Ta Steve
Sir,
What is tipping and pivoting?
Another common type of launching is by Syncrolift or straddle carrier. The largest one can carry over 100k tons. The beauty of the system is that recovery and launch are very fast and put little if any stress on the hull. The layout of the Syncrofilt yard allows many vessels to be worked on simultaneously.
When I worked in Dubai in the 1980s I maintained a fleet of 35 oilfield tugs, supply boats and tug supply boats. We hauled the out at the Al Jumarah shipyard in the Dubai creek. The system was a joy to work withy. No waiting for the tides, the vessel was level so lining up new construction and repairs was easy, the surrounding area was easy to keep clean, and supply and work equipment had easy access to all sides of the ship.
dears
Gorgeous awesome