The riv-nuts idea sounds quick and simple – transom’s about 6CM thick. I do like the idea of the access hatch though – will give extra storage and dry. I’ve had a look around TradeMe and there are some for sale on there, just deciding if water-tight is sufficient or whether I should really put air-tight ones in. Water-tight tend to be bigger and cheaper while air-tight would retain the floatation capabilities – in the ‘unlikely event’. Got some jobs to do around the house first – then will sort it.