Hi Bob,
Yes I know other types of small vessels use this propulsion, but I was refering to the thread of tugs. Only thing I can say about voiths is that they may be simple to use, but they are bloody noisey and do they vibrate. I think though that they may be soon a thing of the past, as the 360 degree screw propulsion units steadily improve, as they are more powerful per engine Hp and easier to maintain than voiths. I could never understand why they fitted the minehunters with them though, as the noise and vibration would set of any accoustic fitted mine, but then perhaps they are supposed too!!!