Get one of these, you wont screw up your truck and you wont screw up your canoe. And its safe, and you won't even feel its there.
http://www.ebay.ca/itm/YAKIMA-DRYDO...Parts_Accessories&hash=item257f8ab1a5&vxp=mtr
http://www.ebay.ca/itm/YAKIMA-DRYDO...Parts_Accessories&hash=item257f8ab1a5&vxp=mtr