Channel Islands TPH Hand Foiled 9.0" Longboard Fin - VolanThe Channel Islands TPH Hand Foiled Single Fin. Built to complement our Tri Plane Hull Single midlength, Devon worked on this sleek single fin that is available in three sizes: 8, 8. 5 and 9. The CI Single Fin template is rather upright, which helps the board pivot and turn on dimewhile its slender outline and conservative rake profile provide a nice flow on down the line point breaks. Our general sizing guideline goes as follows: 8 for 67 & under; 8.