Having worked for years for a major FG bot builder I've seen a lot of partnerships on large boats. THe only successful ones are where the contract specifically identifies responsabilities. A repair and maintenance account must be sent up to handle routine maintenance. It also needs to be clearly understood that if you run over a log and trash the props and shafts that it's the operators responsability for the repair.
Some partnerships are doomed to failure because of not crossing the T's and dotting the I's. Partnerships are a good way to reduce the cost of ownership on a large boat.