What do you mean by Partial Loss of Buoyancy?
Whenever compartments are only partially flooded because their outboard bulkheads contain small holes, cracks, etc, allow progressive flooding to take place. If nothing is done about these holes,the ship will lose buoyancy and list or trim stability.
Partial flooding refers to a condition in which an intact compartment is not completely flooded. This Partial flooding causes what is known as Partial Loss of Buoyancy.
This condition means that the vessel has lost some of her buoyancy but there has not been a complete Loss of Buoyancy yet. The vessel will still remain afloat, although there will be a change in its stability condition.