Re: [Paddlewise] VCP Hatch Deterioration

In a message dated 7/29/00 6:37:35 AM Central Daylight Time, 
rdiaz_at_ix.netcom.com writes:

<< One just basically a cap that fits over the hatch hole rim and is held
 by a built in flange in the hatch itself.  Another kind is a cap but
 with a flexible steel flange that has a latch on it, looking somewhat
 like how the closures on ski boots. >>

Ralph, mine does not have a steel band on it.  At one of the symposiums I 
asked about that since I saw some with bands.  I was told that the design was 
actually the same for both covers.  The main holding mechanism is the small 
flange on the hatch and the mating groove in the cover.  The latching bands 
were supposedly used on the older hatches, but people found out that the 
covers stayed on fine without them.  Gradually for convenience the bands were 
dropped.  I have the same wide "band goove" on the outside of the cover that 
the old covers with the locking band have.  Can't vouch for the accuracy of 
this, but it was what I was told.

>>I wonder what it is about the hatches that makes them so vulnerable to
damage.  I have lots of rubber on my folding kayaks (hypalon) and you
never see anything like what happens to those Valley hatches.<<

One difference I noticed between the VCP covers and the Kajak Sport covers 
(which fit over the hatch rims similarly to VCP) is the stiffness of the 
cover.  The VCP covers are quite thick and stiff.  When you put them on they 
do not stretch out the same way a sprayskirt strechtes.  They just deform 
enough to pop over the flange.  The Kajak Sport covers are much thinner and 
more strechy.  You kind of pull and strech the whole cover more like puttting 
on a spray skirt. 

Several of us had cracks on the underside of the cover.  Some of the 
underside cracks on mine eventually went through to the outside. Since these 
started on the underside, I do not think this is strictly a sun problem.  I 
think it might have to do with something similar to a fatigue fracture cause 
by the repeated stress of flexing the cover to remove/replace it.  If a part 
has to flex in order to work, sometimes thicker and stiffer is not the better 
choice for the material.  If this is the case "years  of life" may not be the 
best measurement.  Perhaps it should be "off/on cylces".  I know that I am 
really bad about forgetting things and/or rearranging stuff so that I may put 
on and take off the hatch 3 to 4 times at the beginning of each paddle and 2 
or 3 times at lunch breaks.

One of the problems with speculating on causes is that there could be 
multiple problems (poor material, outside environmental such as sun and ozone 
exposure, nicks from burrs on the hatch, improper manufacture, etc).  My 
major concern was the thought that I was doing something that was really 
speeding  up the cracking.  I wanted to know how the life cycle for my covers 
compared with others.  Although some people have gotten much longer life, 
evidentally I am getting about what I should expect.  I am going to try to 
work on reducing the "on/off" cylces and sun exposure on my new covers in 
hopes that I can make them last a little longer.

Mark J. Arnold
MJAkayaker
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