Transporting: Bow/Stern Line A Must?

[FISH11]

For the last 3 years I have carried my 14.4 foot Malibu X Factor on the roof rack of my Jeep grand Cherokee. I use the factory roof rack and crossbars and installed some kayak saddles on the crossbars. I put the cross bars as far front and back as they will go. I do not use a bow or stern line, only ratchet tie downs over the kayak at the cross bars. I have driven up to 90 mph (ohhpps, I thing that was speeding) and usually drive 70 mph on the freeway. I have never had a problem even on a trip to the sierras on over 950 miles. If your car is smaller and the distance between the crossbars is less than 4 feet than use the bow and stern lines on kayaks that are over 12 feet long.