Nothing really fancy. Just some 1×6″s cut to fit the contour of the sled and some CLOSED cell foam that will not soak up water for padding. So far so good and nothing has broken yet.
The trick is to make sure your layout is not only very functional but “slam proof”. Make sure hard impacts from any direction do allow gear to move very far. This sled is ultra simple. I have made ones in the past with latched lids, tie downs and even fold out compartments but the weight off adding all that hardware and wood adds up fast.
As for fastening it to the sled I drill the holes through the tub over sized allowing for big pan head screws and allowing for flex of the tub. I also take and drill a small hole in each of the valleys of each runner in the very back, just enough for the water to run when its thawing out in the garage.
Best way to do it is get all the gear you will use…ever. Lay it out in front of you then figure out what you need to access setting up and what you will access when fishing. You notice my tackle box, fish bucket, rope light battery, and gadget compartment in the front are all accessible when sitting and the rod bag, skimmer, propane tank and heater all lock down under the seat. Just start packing it in and find the best pattern. That is the smallest Otter model and I have yet to not have something I need on the ice as my snomobile is also packed and rigged with a auger rack bucket carrier/rack.
PS Missing lunch box sits in the same compartment as the Marcums.
Anyhow a while back I saw a post and Johnny was going to post some pictures of the mods he did to his Otter portable. Maybe they did get posted, if they did could somebody steer me to them. 
I saw JJ was asking about them the other day. I am curious to see them since I am customizing an Otter at this time. (I can’t believe that Johnny would be to busy??!!) Just Kidding Johnny!! 
