In response to a short question from dueitt2s in the Sailing Forum about ice chests, I ended up with a long answer! However, since it rounds out my earlier post (Ice Chest and Storage Options for the Outback and Others) on this subject in the Hobie Kayak Fishing Forum, I thought I would post it here in case others had a similar question.
I have tested a number of different types of ice chests/coolers in my Outback, and have found two that fit the tankwell of the Outback and Sport fairly well. However, I generally carry a waterproof Plano 3741 Utility (i.e., junk and tool) box beneath ithem to level out the rear deck and make the cooler ride a bit better. The white one in the pic below is the Igloo 25 quart cooler from West Marine (and elsewhere). It is just about the right size for drinks, food, digicam (inside a plastic fly box), and even a fish or two. It has all SS fittings, and a hold-down bracket built into the side of the cooler for bungee attachment. However, for fish storage and transport, I generally will use a Sam's Club insulated bag that I carry under the bow bungees.
To secure the Igloo 25 in the Outback tankwell, I attach a small SS shackle to the hold-down bracket on the cooler, and then overhand knot a small 8” bungee with SS fittings (from Boat USA I think) around the shackle, and then attach the bungee hooks to the stock Hobie eyestraps aft. Lowe's and HD sell a similar small bungee, but not with SS hooks.
Here is a pic of the three sizes of small bungees with SS hooks that I have been able to find. The come in 6, 8, and 10 inch lengths. The 8 inch seems to be perfect for securing the Igloo 25 in the Outback tankwell.
Another, slightly larger cooler that rides well on top of my 3741 utility box and fits the tankwell perfectly is the Coleman 28 quart job, commonly available at Wal-Mart for about 10 bucks.
The Flambeau Tuff 'Tainer utility box from W-M (shown above) fits the Outback tankwell even better than the Plano 3741 box, but is not waterproof, this being its main drawback as an under-cooler support box.
Of course, there are a number of other ice chest/cooler options out there that will also work (I list some of these in my earlier post), but use whatever works best for you, as well as whatever is available in your part of the country (or World!).