Two distinct elements to this card:  first, the Tryall Golf Club — still there, outside Montego Bay — and second, that it was mailed by an American sailor stationed aboard the USS William R. Rush.  That was a Gearing-class destroyer in the United States Navy, launched on 8 July 1945, commissioned on 21 September 1945, sold in 1978 to the Republic of Korea to become the ROKS Kang Won (DD-922) but then in December 2016, arriving at Busan Dadaepo port for dismantling.  Servicemen could use American postage to mail letters, and this one did, in 1971.  The postmark shows that.  Grade: 1