Use 3x2 framing with 9mm (inches?) plywood covering. Enclose the entire ski. Make sure you centrally palletise the base (so it 's like a box on top of a PROPER SIZED AND MADE!!! pallet. "copy one.!!!!"--- 4 or 5 width length 4x3's should do it) so forkhoists can easily move it from the side. To be safe it would be wise to allow for a thin polystyrene packing underneath the ski and on the side of the rails, a thicker piece at the front and rear. Before screwing the top down, screw 3 widths of 3x2 (two on top of the gun whales and one (angled) to hold the pole still) packed with thin polystyrene or turf offcuts.
Over screw everything. Roughly black rattlecan the screw lines. That way you can tell if it's been tampered with. Write all info on the crate including booking/tracking reference etc.
For reference have a look at Waterdawg Kustomz Rev hull sale on the site(from memory theres some crate picts) just before Xmas.