Personalized Underestimate Old Man Surfboard Youth Long Sleeve T-Shirt. Funny retired surfer Youth Long Sleeve T-Shirt - Black with surfboard. Never Underestimate An Old Man On A Surfboard. Great gag birthday or retirement gift. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)