Personalized Underestimate Old Man Surfboard Youth T-Shirt. Funny retired surfer Youth T-Shirt - White with surfboard. Never Underestimate An Old Man On A Surfboard. Great gag birthday or retirement gift. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.