Hi, i'm kinda new to the hobby (1 year top), i have really good ideas and have small experience with mechanical systems but i really need you guys

i want to make contra-rotating system for a 40'' tugboat but i'm having a few problem to figure how to properly scale it down, does any one of you have a picture or video of the internal mechanism? it'd help me a lot

my other option is to make an adjustable-pitch propeller but i have the same problem, i have a few clues of how it works but i've never seen the inside mechanism only a few vids showing how it work in the outside (no fun )

A tug with counter rotating props, one each side, is not uncommon. Contra rotating on the same shaft is not. It is torpedo rather than tug territory. Is it a particular tug you have in mind?

1 lefthand pitch and one righthand pitch prop for a 40 inch boat require 2 x 3" inch or 3 1/2" inch props 2 motors fed from the same battery ? just change wiring to get left hand rotation motors don't need anything fancy couple of 12v battery drill motors , old gmc drills make good use of what you can scrounge my next tug is the ocean tundra 48" contra rotating in korts nozzle if you have some time spare , facebook ( Bridgetown model boat group ) there you will see images of my tug I built 45 year ago its only a single prop 4" inch , I built that prop 45 year ago ,,, also there are 2 new built props left hand and right hand 5 blade destin for the ocean tundra ( the motor in the flying duck , is a cut down vw windscreen wiper motor the frame around the armature is brass fabricated ,,, 50 year ago I canablise anything , there was nothing around
chas