Four rubber blocks and some proper rope is all you need to tie down your canoe to your truck. With a cap it's a lot easier to tie it down so be glad you have one. There are lots of places that you can tie your canoe down on. You may need to get under your truck a bit, but there are lots. I got a set of raised blocks from somewhere that are more than twice as high as the regular set of blocks. I put these at the back and slide the canoe as far forward as I can. THen tie the front of the canoe to the front bumpers or under if you have to. Now go to the back and pull your canoe to the back and tie it down. You can also run a rope from each sit of your yoke down the side of your truck and under, to make extra sure that it doesn't move. Use good braided poly blend rope the 1/4' stuff at canadian tire is plenty. ( If its too big its too hard to knot) Its soft enough that it souldn't hurt your paint as long as its clean. Use the following knots to tie down your canoe. With these knots and good rope I normally only use stern and bow lines to tie down my canoe. Unless I plan on tranporting it at 120 km/h on a windy day then I add a belly or yoke strap.
Knots, Fasteners, Lines
Truckers Hitch or Cinch Knot Use the Truckers Hitch for tying the boat down to your roof rack on the car. The loop gives you a 2 to 1 mechanical advantage in tightening the rope. It also gives you the advantage of pulling down with your weight as you pull.
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http://www.nhamcpaddlers.org/images/truckers_hitch.gif for image
Form a loop through a simple knot leaving enough rope to loop around the roof rack and back up through the loop. Pull down on the end going through the loop and once it is tight, tie off the end to securely fasten the canoe. Also make sure bow and stern lines are securely fastened. A loose line catching under a tire at speed can do serious damage to the canoe and potentially cause a very serious accident. - Rod Dore, 11/98
Using good rope and the proper knotting technique makes all the difference in the world. Your canoe shouldn't shift on the highway. Unless you want to see it on the side of the highway in a few pieces. I have herd of a kevlar boat the shattered, because someone didn't know how to tie it down.
Hope that helps.
