First and foremost, I don't know. With that said, it is as chawk_man says about good maintenance and conservative treatment of the equipment. There are just so many variables.One way you might rationalize this question and put it into some sort of perspective is to consider today's automobile life expectancy. Most of us are very familiar with the mileage of the family grocery hauler.
Let's say you could average 50 miles per hour over the life of the vehicle. That would put the 3,000 hour life that chawk_man fully expects at a very reasonable and very do-able 150,000 mile lifespan for your car. I am a bit more demanding of my autos and expect to get over 200,000 miles which would equate to around 4,000 hours. Then, again, I've recently owned 2 cars that I drove well over 300,000 miles with no major repairs.
Of course, we ain't talkin' about cars per se and boat operations are for sure a bit different. But, it's one way of getting your head around the equation.