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Large Barge Loaded On Cradles At A River Nile Slipway  
Design & Manufacturing
Mechanical Applications & Systems




Slipways are ramps built to connect rivers to river banks or seas to sea shores. They allow boats and barges to get in or out of water. Such small vessels are first moved down slipways during inauguration. Once in a while, they are moved upwards for repair, maintenance or overhauling purposes and then moved downwards when ready to go back into service. Efficient slipway operation calls for the use of appropriate machinery with adequate design and sufficient safeguards. The right slipway machinery must provide the target lifting capacity, suit the site topography and ensure safe vessel handling.


Some appropriate slipway machinery was needed to operate a slipway located at Shobra El Kheima; a north-eastern Cairo suburb overlooking The River Nile. Due to the narrow river bank at the location, longitudinal vessel movement was not feasible and boats and barges had to be laterally moved up or down the slipway. Coping with these requirements, our design team came-up with an effective solution for a range of vessel size and weight. Design work was solely carried out by DMMAS. We partnered with The Arab Contractors ; one of the leading construction companies in the Middle East and Africa ; to manufacture a 200-Ton Capacity slipway machinery.


Three cradles are mounted on bogies to move along rails. Provided with 4 bogies and 8 wheels, each cradle is pulled along a separate pair of rails by a 600-meter wire rope wound at its free end over a separate drum. Power is provided by a 75 KW electric motor. The slipway keeps an 8-degree inclination to the horizontal. The 3 pairs of rails extend for 40 meters along the slipway keeping a 15-meter center-distance between adjacent pairs. Rails are welded in a strong steel structure fixed to a concrete block laid over compact rocks and protected with sheet piles. Pulleys provide 90-degree wire rope redirection. Drive and controls are secured in a control room.


Cradles go under water, carry vessels, move them up the slipway and reverse this process when the repair work is over. Three drums work separately; each controlling a cradle. So, the working load can be increased to double or triple a single cradle capacity. The vessel size changes accordingly. The load carrying capacity of each cradle is 70 tons. Three operational situations are possible. One drum can be operated to lift a 70-ton small boat. A small 40-meter long 140-ton heavy barge requires the operation of two drums. Large barges of up to a length of 55 meters and a weight of 200 tons can be lifted through 3-drum operation.


Stepped operation is guaranteed and enough security measures are taken. Power ranges from 46 KW to 75 KW. Speed varies from 750 RPM to 1500 RPM. Cradles move at a speed ranging from 2 meter/min to 4.4 meter/min.The electric motor is provided with electro-magnetic brakes. Additional hand brakes are available. Programmable logic controllers are used to secure operation.


Different machinery may be adopted to operate different slipways. The design of slipway machinery is not as straightforward as it might seem. It requires knowledge, experience and vision. You may be in the process of building a slipway to repair small vessels traveling along some local waterway. A good idea is to get some expert consultation. Just brief us about your project. We are ready to provide advice. We are even ready to supply the machinery necessary to operate your slipway in the most effective and efficient way.





  Barge Approaching Slipway Cradles Extending Under Vessels Slipway Control Room  
Barge Approaching Slipway
Cradles Extending Under Vessels
Slipway Control Room
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