If the exhaust is a wet exhaust then I can't see an advantage here, mind you the Dutch do things very differently to us in the UK. Are you sure its not a cooling line ?

@@dhcrouchmarineltd3049 not the cooling tubes, they are each side of the keel, it's an underwater exhaust.

@@romakayak I have to admit its something I have seen here in the UK. However I cant see any advantage. I would be inclined to modenise it.

If you read the manual for the gearbox it may help you. If you mean spinning the prop in a free spin due to it being dragged then it depends. If oil is only splash fed how is that splash achieved. if its from a gear or oil spreader which is powered then the output bearings may not get any lubrication without engine power. If the oil sump has the output gears partly submersed then it should be ok. Oil pressure is usually for bearing shells and solid bearings. Ball bearings typically don't need high pressure oil flow. It depends on the application. For example the BMC 1800 has to have an oil feed to the injection pump drive bearing because of the engine block being reduced as compared to the 1500 BMC. Again high oil pressure for working on mechanisms under high workload. The PRM range of gearboxes are splash fed gears but oil fed bearings. But this wont work if the engine is NOT running. As they are designed for all manner of ships boats etc they considered a free spinning propeller and ok. However if a propeller is allowed to free spin as a serious speed then I would be very concerned at a lack of lubrication and would consider a shaft brake. Hope that helps