t1=d1 is a board for use in water/(wind/kite)surfingboard/bodyboard/wakeboard of material/property t2.
From tanbo, djacu. Also sufingboard (=bonjacta'o), windsurfingboard (=fanjacta'o), kitesurfingboard (=volfanjacta'o), wakesurfingboard (=blobonjacta'o).