What type of a Rib is this?

[two stroke mick]

I was passing R S marine outside Westport on Sunday and I noticed this rib. The tubes are bolted in place or held with a rail system. The transom is semi open (gaps on RHS and LHS). The Rib would appear to have been rigged with twin out boards in the past.
There was no plate on the rib to indicate make. So who made it. It looks like a very heavy well made Rib.

[paulbrown22]

I'm no expert RIB spotter, but with the (presumably) planing pad at the stern, the twin engines and the self righting frame, an older ex-RNLI Atlantic or something similar?

[GuyC]

From Google images, I'd agree and say an Atlantic 21.