[Paddlewise] Truck Cabs & Racks, was: Cradles/rollers for EuroVan racks?

Erik Sprenne writes:
 > 
 > I drive a Mitsu pickup, and on this vehicle the truck bed 'flexes' and moves
 > independantly of the cab of the truck.  I've got three racks/crossbars I
 > *can* use - two on the cap (which is on the bed of the truck), and a third
 > rack on the cab of the truck.  For carrying whitewater kayaks and solo
 > canoes I use only the two racks on the cap.  For carrying the sea kayak, I
 > use saddles on the rear-most cap rack and on the cab rack - but am mindful
 > of the independent movement of the cab and the bed of the truck.  Until I
 > worked out my optimum knot system, I had the ropes come loose several times,
 > but with the bow line, no damage was done.  The saddles help absorb the
 > stresses due to the differential movement of the two crossbars, and insulate
 > the sea kayak from the twisting motions.  With the tandem open boat, I tie
 > it down to all three racks - the Tripper can take the twisting and the
 > differential stresses....

Thanks for posting this Erik!  I have the exact same system set up.  I 
bought fixed yakima bars because they have take a higher load than the 
sliding/flexible system.  So I ended up with 3 bars.  For my WW boat,
I load up the last two bars, when putting on the sea kayak I have
hulley rollers in the back, skip the middle and use cradles on the cab.
 
rollers xtra bar  cradle
  oo____o_______  __*__
 /              ||     \___
/               ||         \
  Truck Canopy    Truck cab

When the owner of the local Kayak shop saw this he warned that he had
heard of kayaks getting stress fractures from the independent movement 
of the cab from the truck body.

My ?: has anyone else heard of this happening?  If so, what can I do
to prevent it from being a problem.

My guess is that I don't want to tighten down the strap over the
cradle.  I tie the kayak down bow and stern in an inverted V to loops
(actually a U) bolted to the front and back of the car (front right
and front left bumper and rear left and rear right bumber, just on the 
side as the bumper wraps around on the front and on the rear for the
back bumper).

rear view
kayak on top right on hulley rollers with a tie down to rear right and 
left bumber U bolts.
      
  ___o\/o
 /  .   .\
/__.____._\
| .      .|
|u_______u|
||       ||

Is this configuration going to still put too much stress from the
independent motion of the cab?  Is my only other recourse to give up
the bar over the cab and install a fixed bar on the furthest forward
part of the canopy?

My only other thought on this is that the stresses would be dependent
on the driving conditions.  If I was driving off road or on very
rough roads the cab vs. body of truck motion would become more
extreme.  Any thoughts on this?


----------------------------------------------------------------------
snark_at_tulgey.org     aka Glen Acord	  http://www.tulgey.org/~snark
	if ($snark eq "boojum") {vanish("softly","suddenly")}



***************************************************************************
PaddleWise Paddling Mailing List - All postings copyright the author and not
to be reproduced/forwarded outside PaddleWise without author's permission
Submissions:     PaddleWise_at_PaddleWise.net
Subscriptions:   PaddleWise-request_at_PaddleWise.net
Website:         http://www.paddlewise.net/
***************************************************************************