Abstract: A mast foot assembly for adjustably and releasably holding a mast to a mast track disposed on a surface of a sailing device. A base member is disposed on the upper surface of the mast track and has a pair of first bores at respective ends thereof disposed over the slot. It also has a central mounting portion between the first bores with a second bore therethrough normal to the upper and lower surfaces and having a first slot communicating between a side of the base member and the second bore. There is a retaining key member sized to slidably fit within the first slot in the base member and having a second slot communicating with an inner end thereof. A pair of nut members each having a treaded bore therein are disposed under the lower surface of the mast track. A pair of threaded members are carried by the base member and pass through respective ones of the first bores in threaded engagement with respective ones of the nut members.