I don't understand why there is such a bias in standard design model tug thinking against Steerable Kort Nozzles.
Both the Mini Tug Towing topic & the Springer design do not allow steerable Kort Nozzles. Why? They improve towing enormously & should be encouraged & not banned.
If you go to one of the "professional" tug towing events you will see little else so why ban them elsewhere?
Korts are easily & very cheaply (cheaper than brass blades in standard rudders) made from plastic tube with bathroom waste 40mm at the small end & 110mm drainpipe at the larger end & they improve tug agility enormously & help a model get near the agility of a real modern tug with its advanced drive systems. They are also available commercially from Mobile Marine Models & others. You can use perfectly standard propellers with them without any difficulty. The motor/ prop in the first photo is a Graupner Multispeed 380 2:1 exactly as supplied by Graupner & ideal for beginners.
The boat in the first photo below was made in 1990 & it still works just fine. The Kort is based on a sink drainage pipe of 40mm. The second photo is based on 3.5inch drain pipe.
Neither was made particularily well - just look at the photos - both were made by someone (me) in their first 6 months of modelling who cringes at the photos now & both are still in one piece & working after 20 years. I provide the pictures to demonstrate just how basic they can be! They both give great agility to the models that they are attached to.
Or is it that most modellers are stuck in the 1950's???
There that should be provocative enough to get some discussion.