Abstract: A nautical light for watercraft includes a cylindrical metal housing having opposite ends, one of which includes a collar for mounting the light on a tubular mast or pole. The housing includes a pair of vertically tiered light chambers each having a lamp bulb coaxial with the housing axis and a window opening radially thereinto through the housing. A cylindrical closed end lens is axially received over the housing with the closed end of the lens overlying an end wall of the housing opposite the mounting end. The lens member is sealed with respect to the housing, and the closed end of the lens member is fastened to the end wall of the housing to facilitate removal of the lens for access to the light chambers. The housing and mounting collar provide a path for heat transfer to the mast on which the light is mounted, thereby providing thermal protection for the lens.