It looks like am interesting retrofit job. You can see the newer plates welded over the hole the prop shaft used to come out of and the rim drive...
That's certainly fair - I missed that particular bit. I did subsequently find this product from Brunvoll that may be promising:...
This looks like it's in production: http://voith.com/corp-en/drives-transmissions/voith-inline-thruster-propulsor.html
