We have had a Webber BabyQ for about 6 months now. I replaced all the mild steel
nuts/bolts etc with stainless steel
so that, except for the actual bbq plates, there is only aluminium, stainless and plastic, so nothing to rust.
Mounted on some HDPE sheet with fastenings that go through the plastic feet, that also double up for the rail mounts on the front edge with an old stanchion to the lower stern rail to support the back of the BBQ.
No pics to show detail, found one that shows the general idea.
I figure I can go through 3 of these for about the same cost a good so called marine
BBQ. Very happy with it so far.