"The high primary stability of a double when paddling on flat water can lull paddlers into complacency. Doubles are hard to self-rescue, particularly in "conditions". From a risk/rescue standpoint, paddling a double or triple is essentially paddling solo"
Moulton, I think the above sentences are self contradictory:
1) as doubles actually have higher primary stability [as you state], from a risk standpoint paddling a double[triple] is NOT essentially paddling solo [ie from a risk standpoint].
ie a double is safer than a single from a risk standpoint. . . . especially for inexperienced, unskilled etc.
2) "doubles are hard to self-rescue . . . "
'self-rescue' needs to be defined for this, but I would say in a desperate scenario - self rescue at the minimum means getting the body somewhat out of the water and supported by the kayak. This is possible by beginners if they pull themselves partially up from either side with their feet still kicking in the water on ea side. ie it is more achievable and balance-able by beginners than single kayaks and in this aspect doubles also are safer from a risk/rescue standpoint.
Now, I have not seen what type of double they were actually paddling, but base the above on what a typical double seakayak configuration is with individual ckpts and bulkheads. If one of the combined ckpts with no bulkhds or minimal floatation, most comments above are less appropriate except one might still think that some initial stability is higher for their typical wider [tho' shorter]
body form and boxier cross-section.