For your consideration, here is a Vintage Boat White Rope Guide Part, Marked RP on the side.  It is worn and has paint lose on it.  It measures 4 7/8 inches long and 2 3/8 inches at the widest.  It is 2 7/8 inches tall.  The base measures 4 by 3 3/8 inches.  Item pictured is the actual item up for sale and comes from a non-smoking household.  (445.913f-.13B5)