Your engines stalling reminds me that a similar thing happened to my husband in a Quinquari (I think that's what is was) when he was doing sea safari at the Corrywreckan many years ago.
A bit of misinformation here as certainly not a Quinquari Vessel as they have only been supplied to that area in the last 2 years.
A point though for all to bear in mind that there is no perfect vessel for every situation. RHIBs have come into their own as they have proved so versatile but they will still have their limitations.
A common assumtion is that being a RHIB it cannot be swamped. If it is a transom RHIB, as most are, then it can. In most cases this is whilst the vessel is underway, or capable of being put so in a short period of time and the bulk of the green will go over the transom and good bilge pumps will clear the rest. As John W. has found out there will always be a set of circumstances to keep us all on our toes.
Of course if Johns boat were not a RHIB it would have had no buoyancy on swamping and would now be part of the long list of Goodwin wrecks. I would like to think that it is testomy to the hull and systems together with Johns determination in that the vessel was recovered and put back into action in days.
It is interesting to note that Coding requires a minimum of 250mm transom height and as such can be seen to cause captivation of water. If you want a truly self draining RIB for a particular activity then the Ocean Dynamics with inboard will come to the fore.