Rack system failure

 
  Once I have my OB secured to my yakama racks I grab the back end and shake the snot out of it.  Fortunately I haven't dislodged the hull yet by doing this, and this tells me the yak is secure.
 

What kind of car or truck was it?

  Once I have my OB secured to my yakama racks I grab the back end and shake the snot out of it.  Fortunately I haven't dislodged the hull yet by doing this, and this tells me the yak is secure.
 

Same thing i do with my Thule rack then I add bow and stern lines. Drive through the dips to the gas station check. Then about 20mins through the hills and turns i check it again just to be safe. Still havent felt it loosen up at all.

one reason I'm glad to be done w the plastic yak, seems way too heavy for standard racks