After a long hard decision to install a bow thruster we decided to go ahead to be told 125mm tube was the max tube size! which is ok if it's just for light manoeuvring, perhaps with no wind or tide in a marina. We have a forward head in the bow but I had heard of a 411 having a 185mm tube but the toilet plinth had to be removed and raised, so that is what we opted for. Osmatec at Porthamble has done a great job installing the tube and thought it might be of interest to all 411 owners of some pictures of the tube area glassed in. The intention is to point the motor forward to the bow and the Black water tank raised as high a possible but will keep you posted. Then make the toilet plinth removable for access to the bow thruster if required to repair or service I will ad the pictures on the picture section if it will let me or send me a mail and I will forward the pics if required.