tback,

It's not only the cat trax resisting lateral movement.
You will notice the dolphin striker strap drops into two slots and the there are two retainers that go over the front beam.

Take the cat trax away and put the back of the boat on a slippery surface and you still won't get any lateral movement.
The cat trax are just an added bonus.
Its a good setup.
Regards,
Phill

I know that the voices in my head aint real,
but they have some pretty good ideas.
There is no such thing as a quick fix and I've never had free lunch!