Firefighters were called to a boat sinking at a marina at Chiswick Quay in Chiswick.
A 14m Dutch barge used as a houseboat was submerged and was obstructing another boat from moving.
Crews pumped water from the vessel and moved and secured both boats to a place of safety.
Fortunately, there were no people involved and no one was injured.
The Brigade was called at 1059 and the incident was over for firefighters by 1247. Three fire engines from Richmond, Acton and Hammersmith fire stations and two fire rescue units from Heston and Battersea fire stations were at the scene.