Just picked up on your build the other day and you've done a great job and it looks the part.
Some months ago while I was waiting for my Albert kit to turn up, I cut up some scrap timber and ply and started on a Dredge Tender. Just a couple of inches longer than a Springer, but I thought it looked sort of cute.
He's now at the almost complete stage, but just now making up a heap of wheelhouse details, because of the large window area it needs some clutter within and without. It's only a day cab, so there won't be benches and stuff like you have in yours
I was interested in the conversations on your build regarding rudders, and on Derrick I made a pattern and cast some in Urethane to the photos I had showing the wide horizontal fins on both sides of the rudder. It should be quite effective, but he hasn't been wet yet, so that is still an unknown.
Derrick is powered by a 12v car aerial motor, direct driving a 50mm 4 blade tug prop, so down on revs but up on thrust. Initially he'll be powered by 6v gel cell, then maybe 7.4V lipo, or if all else fails, 12v Gel. Hopefully the performance will be adequate.