All weather lifeboat launched at 2315 to 30ft Yacht aground on Grain Outfall and taking on water. 1 person on board, ALB on scene at 2318, Yacht being illuminated by Svitzer tugs Monarch and Harty. ALB closed the casualty and managed to recover the occupant from the forward part of craft, which was by now almost under water. The person apart from being wet, had suffered no injuries. ALB returned to the boathouse to await Sheppey CRT, whilst waiting, the ILB was launched to attempt to secure the yacht to the outfall beacon. The ALB returned to provide illumination and safety cover, the ILB managed to successfully secure a rope between the yacht and beacon, thus avoiding a navigational hazard. Both lifeboat returned to station at 0040, ready for service at 0100. SW 2.