Per Vic Smith:
If the 2x6 only needs to be restrained side-to-side, front-to-back,
rotate the blocks so the cavities are on top. Then, put ~5x5 inch
"nubs" on the underside of the 2x6 to fit within the hollows of
the cinder blocks. This will keep the boards from shifting -- but
not prevent them from being lifted off the blocks.

Note that you might wish to use "half blocks", instead. I don't
doubt they would adequately support the kayak's weight as well
as the full blocks -- yet would be half the size/weight (and
still have a single cavity that could be exploited by these "nubs")


Best solution yet.

It occurred to me, but I had two reservations:

1) Part of the idea of this setup *is* to make it hard to move.
Heavier is better and I will apply the fastenings on-site.
We're thinking bored kids and the occasional nighttime drunks
here....

2) I have zero experience with sand, but it seemed like flipping them
hollows-side-up/down would accelerate any tendency for them to
sink into the sand.... less surface area...


Right now, my breadboard implementation is using blue screws and
it seems solid enough. Installation time comes, I'll remove the
screws and flip the blocks over and drill fresh holes.

I think Liquid Nails construction adhesive is also going to come into
the picture because experimentation with placing/removing the boat
indicates a need for some padding.

Got some of that Norsk multipurpose flooring (the stuff with the
scalloped edges so squares can be joined) laying around. It seems
pretty durable, so I'll Liquid-Nail it in place for the final setup.
--
Pete Cresswell