I put this together on Keel Blocks and Keel Block Failure
Keel Block is a simple thing. A reinforced concrete block lined with wood on which a ship rests.
Keel blocks can be seen kept in the courtyard right of dry dock
The dockmaster prepared the layout based on the specific ship, like the blocks being laid out here at HSL using cranes to place
Even Uncle does the same thing. Here is Pearl Harbour dry dock and destroyers on Keel Blocks.
Note how close the hull fins are to the blocks. Docking is a intricate and exact exercise.
Even ships of size of INS Viraat is put on keel blocks
More recently, INS Vikramaditya had a refit at Cochin Shipyard Dry Dock. It was thought a ship of that size could not be accommodated in any yard in India, but CSL did a fantastic job.
For Pontoon Launch of new ships like INS Khanderi, it rests on Keel Blocks and floats up when the pontoon is submerged.
Typically Keel Blocks are made by contractors or the dockyard. While all blocks should be rigorously tested, maintenance pressures may cause only some from a batch being tested.https://www.google.co.in/url?sa=t&rct=j ... 4172,d.c2Ihttp://www.hegerdrydock.com/libraryPdf/ ... 20Navy.pdf
Yet Keel Block failures do occur. Its not uncommonhttp://www.sname.org/HigherLogic/System ... 68c584a8b6
The other probable cause is equilibrium during undocking.
As per the earlier posted ToI report, the CoI is examining both probable causes.