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:

  1. Gravitational type launching
  2. Floating-out type launching
  3. Mechanical Type launching
  4. 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  ship launch roller slideway and under its own weight enters the water. Oil or wax is used to assist in the sliding process.

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


ship Slideway Launching The side oiled slideway launching system is also one of the most widely used ship launching systems. This type of system is mainly of two types.

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) ship in dry dock The floating-out type launching system is a simple, effective, and safe procedure. Though the initial investment is high, this type of method is most widely used by shipbuilders.

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
  • mechanical ship launch Mechanized comb slide
  • 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.

air bags launching

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

Disclaimer: The authors’ views expressed in this article do not necessarily reflect the views of Marine Insight. Data and charts, if used, in the article have been sourced from available information and have not been authenticated by any statutory authority. The author and Marine Insight do not claim it to be accurate nor accept any responsibility for the same. The views constitute only the opinions and do not constitute any guidelines or recommendation on any course of action to be followed by the reader.

The article or images cannot be reproduced, copied, shared or used in any form without the permission of the author and Marine Insight. 

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About Author

Raunek Kantharia is a marine engineer turned maritime writer and entrepreneur. After a brief stint at the sea, he founded Marine Insight in 2010. Apart from managing Marine Insight, he also writes for a number of maritime magazines and websites.

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  1. 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.


  2. 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.

  3. does the airbag method also work on gravity? except that it uses airbags instead of slideways/rollers?

  4. 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

  5. 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

  6. 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

  7. 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.

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