Re: [Paddlewise] Wind forces on roof mounted kayaks

At 11:56 AM 4/22/98 -0400, you wrote:
>
>Could you explain to me why you use lines to the back of the vehicle?  I 
>almost always use 2 lines to the front of the car, but don't bother with any 
>lines to the back.
>
>
>kirk
>***************************************************************************
Kirk,

If you tie a boat with two lines to the bow and I tie with one line to the
stern and one to the bow we have the same number of lines and tiedown
strength, assuming we use the same material.  My feeling is that they would
perform the same if the vehicle didn't move.

Now let's talk about probable failure scenarios.  I expect the bow (and
stern) line to be needed when the saddles alone no longer hold the boat.
This can happen:

	1.  When I'm driving really fast.
	2.  When I'm driving sorta fast and more wind comes from nature and/or
		a passing vehicle.
	3.  When I have to make a PANIC stop!!

So, sometimes the boat wants to slide forward and sometimes aft.  The
length of my bow and stern lines is unequal, as is the angle they make to
the ground so that I know only one will be stopping the slide initially.  I
expect that a single line has that strength (and, I hope, so does the
attachment on the boat).  The second line is therefore a backup.

With your scheme, even if you use two independent lines at the bow, I would
expect you to use the same attach point on the boat.  So all your holding
power is from one attach point.

My way does have a down side.  I carry my kayaks on the roof of a Dodge
Caravan.  The bow lines travel aft from the front bumper to the bow(s) so
they are over the hood.  The stern lines travel aft from the rear bumper to
the sterns thus allowing people in mall parking lots to walk into them.  I
generally hang a flag from one stern and truthfully this hasn't happened
yet, but I think it's possible.

I think that there's more than one way to tie down boats and the important
thing is that we use a method that works reliably.

Bill
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