US NAVY SEABEES "CAN DO!" Challenge Coin - Fast Shipping. This is a great looking US NAVY "SEABEES" commemorative challenge coin. Coin has reeded edges and is about 1 9/16" in diameter. All details are raised lettering. Coin is contained in an acrylic air tight holder and displayed in an attractive blue velvet presentation box which will make this a very impressive gift. A Seabee is a member of the United States Naval Construction Forces (NCF). The word "Seabee" comes from initials "CB" which in turn comes from the term Construction Battalions. The Seabees have a history of building bases, bulldozing and paving thousands of miles of roadway and airstrips, and accomplishing myriad other construction projects in a wide variety of military theaters dating back to World War II.