Find yourself an insulated container. Something that can hold enough volume to hold your worms, that you can easily manage and that maybe as a bit of room to spare. The extra room you can use to put a few mini ice packs in. By mini I mean the little icecube sized ice packs that you can buy in a sheet and then cut up into individual parts. Wrap a couple of those in paper towel and put those in the bottom of your container and then put the worms and some of their material in on top of that.
I found that the finding of something that works for you is very much a personal choice thing. I found 2 Stanley brand containers a year or two back but have never seen that model again. I still use those and they work well. I also have another type that I found just looking in your local stores 'lunch container' area.
I took a few picks of what I have for reference.
-2 Stanley Brand 10oz containers:
https://picasaweb.google.com/brian.haymo...8367650962
https://picasaweb.google.com/brian.haymo...2714215890
https://picasaweb.google.com/brian.haymo...6255912178
-Aladdin Brand container with 2 sections next to one of the Stanley for size reference:
https://picasaweb.google.com/brian.haymo...6913914818
https://picasaweb.google.com/brian.haymo...5953286770
https://picasaweb.google.com/brian.haymo...3056776306
-2 mini ice packs in bottom of aladdin container:
https://picasaweb.google.com/brian.haymo...0234418962
My two stanley containers each hold a sandwich sized bag of bait. The Aladdin one can also take a sandwich bag's worth of bait in each side of the container or slightly more if you take the insert out and don't use it. Taking things that are not alive like minnows, cut bait or such partially frozen keeps them cool enough for a partial day trip that you don't need the mini ice packs but the worms really need it.
I've done well with the above containers but recently I did find a cooler that would fit on my Scadden Freestyle H3 V tube and offer very good access. It does not take up the full area behind the seat, though I think the area behind the seat is bigger then a fc4 since I'd expect the fc4 to be the same as the fat cat / super fat cat and my cooler does not fit a fc/sfc. My motives were to have a place I could put bait and keep them cooler longer and easier. It's also nice enough that I can divide the cooler enough to have a 'for the fish side' and 'for the human side" so I can keep a water bottle or small amount of food for an on the water lunch of needed/wanted. I'd rather not have my sandwich sauced with carp meat juice if you know what I mean. Here is a pick showing my cooler, kind of hard to see but...
https://picasaweb.google.com/brian.haymo...3679947538
My brother in law has a SFC and a cooler that he thinks will work for his tube. Not sure if he has tried it yet but the cooler he has is this one:
http://www.igloo-store.com/detail/IGL+ICECUBE+14
If you put the cooler in so the hinge of the lid is toward the tip of the V of the tube we found that getting the cooler to open and getting your hand in it is really no different then using the tubs we both have been using to keep our stuff out of the water that's in that area.
Sorry longer reply then I'm sure your after but figured I'd share since there is more then one way to tackle the need you brought up and personal preference and space available really will be the drivers for your choice I'm sure.
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