All weather lifeboat launched at 1005 to a 21 metre Wind Farm transfer vessel, which had struck an unknown underwater object, 2 crew and 4 turbine technicians onboard, vessel taking on water and stuck fast on object. Whitstable lifeboat and another windfarm vessel proceeding. ALB on scene 1040, portable pump and two crew placed onboard, along with pump from Whitstable. After continuous pumping, the vessel seemed stable and eventually floated free from the obstruction, after sealing the compartment and with engines running, the vessel proceeded slowly under its own power towards Whitstable, with Sheerness and Whitstable lifeboats escorting. The vessel eventually secured on the Quay at Whitstable and the ALB was released, returning to station at 1340. Southerly 3.