Sure Ron, Let’s see if I can put this in the correct terms…Basically the oak rails between the two bunks turn them into a single rigid platform in this case for loading logs onto. Since the bunk on the rear bob is rigidly mounted to the beam and the front bob has a swing bunk (meaning the bunk pivots on a heavy pin dropped through the center of the beam) that lets the front bob pivot under the load for the whole sled to follow. Picture it like an old wagon and replace the sleds for wheels and you can see how the front “axle” must be able to pivot independently from the rest of the rigid wagon bed.
Having a solid deck built on the sleds achieves the same purpose, as I have had it set up the past two winters. By removing the deck portion it brings the log platform down to the bunks themselves and therefor closer to the ground making it easier to load and removes unnecessary weight.
Finally having the oak rails bolted on the underside of the bunks, it makes a very convenient ledger to rest poles on for rolling logs up onto the sled.
If anyone has more insight to add to this please feel free. -Joel
