Winston Grennan, 56, an innovative drummer known as the inventor of the “one-drop” reggae rhythm and an original member of the influential group Toots and the Maytals. Born in Jamaica to a musical family--his mother, grandfather, grandmother and many uncles played in local bands--Grennan started playing homemade drums as a child. After a brief and successful career as a professional boxer, he turned to music and became a popular session drummer for Studio One, Treasure Isle and Island Records in Jamaica. Grennan played for hundreds of classic reggae hits by such artists as Bob Marley (“Rock My Boat,” “Satisfy My Soul,” “Concrete Jungle”), Jimmy Cliff (“Many Rivers to Cross,” “The Harder They Come”) and Carl Dawkins (“Baby I Love You”). Grennan was a prolific composer, and his “Savior” was featured on the soundtrack of the film “9 1/2 Weeks.” He also performed with pop and jazz artists such as Paul Simon, Dizzy Gillespie, Freddie Hubbard, Aretha Franklin and the Rolling Stones. Since the late 1980s, he had performed with his Ska Rocks Band, playing American popular music combined with Caribbean rhythms. The “one-drop” rhythm, as described in the New York Times obituary on Grennan, “is a sparse, unhurried beat with a bass-drum accent--the one drop--on the third beat.” On Oct. 27 in Nantucket, Mass., of cancer.