I have a 3.1m inflatable. I use this
http://www.penguindirect.co.nz/fishing/sea-anchor?product_id=53 not too sure if it is the best size for my inflatable after reading up on some of the comments here & elsewhere on this forum... they seem to go for the next size up. It needs a float so when the drift starts to slow down, the float will stop it from sinking. My expereince with the sea anchor is still - work in progress. Have found it best to set it at least 5-6m back & with safety in mind, needs a quick release knot, to let it all go if some of the chop decides to join you in the boat
Check out their collapsible live bait bag. In my view, is much needed on an inflatable with its limited leg room, the live bait bag is tied off to the outside of the boat, good to keep your catch in as well.... you will use strong words when you motor off & its still outside the boat ..haha
http://www.penguindirect.co.nz/live-bait-bag-round?search=live%20bait