Side Transfer of Vessels on a Floating Drydock

Shipyards utilize many different ways and means to launch the vessels they build. Depending on shape and size of the vessel, available facilities and environmental restrictions, these methods can range from using travel-lifts, ship-lifts, launchways with rolling cars or greased surfaces, building the vessel in a graving drydock and then flooding the drydock to launch it, or utilizing floating drydocks where the vessel is rolled on to the drydock which is subsequently submerged to launch the vessel. Transferring, and subsequently launching, a newly constructed vessel using a floating drydock is more commonly accomplished with an ‘end transfer’ where the vessel is rolled on to the pontoon deck of the drydock in a longitudinally oriented manner. In rare occasions, due to site restrictions, the vessel is transferred on a transversely oriented drydock, which is generally referred to as a ‘side transfer’ operation. This type of operation presents many challenges like removal of an entire wing wall on the drydock to accommodate the vessel transfer, aligning and holding the drydock’s pontoon deck level with the land facility over varying tides, ballasting the drydock to maintain levelness as the vessel rolls onboard and other considerations unique to this type of transfer.