Thunderbolt HI4 9'1 Longboard Surfboard9'1" x 22 9 16" 2 3 4" 64. 5L he HI4 is Harleys go to performance longboard for anything up to slightly overhead surf. Its wider overall with a more curvaceous plan shape between the feet, making it exceptionally loose and easy to maneuver. The design includes the continual HP rocker with a slight flip in the last six inches of the tail, enabling control even in the pocket. The combination of an even rocker, nose concave, and wider nose makes the HI4