4 blades on a tug matey…….especially built for torque and low revving grunt.
you will find that all steam tugs of that era had high “steam pitch” on the blades of the prop to give high power at low revolutions of the engines when towing
, ……
……..and with a 5mm shaft……length dependant on the size of hull and where you want your motor to sit in the hull.
neil,