Jackshaft pros and cons

[Capt Sport]

I'm interested in jackshaft power for my next boat. And, was wondering if some of the more experienced designers on here could tell me the pros and cons of powering this way.

It seems to me that a boat with jackshafted power would be much better balanced, ride better and be more efficient. But I'm sure I'm missing something, or more boats would be built this way. It can't just be that outboard boats are cheaper to build.

Just to give a little background on the boat I have in my head:

Aluminum
Center console or center pilot house (full walk around)
24-28' lenght overall
8'6"-9' beam (dependant on length)
diesel power

What I'm looking for is a rough water boat, with extended range (80-100 gallon of fuel). That is as cheap to run as possible. Think of it as some of the Pacific north west boat designs without the great big full width house and cabin. I'm not looking for the fastest boat on the water either, cruse at 20 knots top out at about 30 knots.

Thanks in advance for you help and input,

jr

[TerryKing]

Capt, A jackshaft (typically with universal or CV joints) can connect the engine to a conventional propshaft/shaftlog with thrust bearing, OR a Vee Drive, OR an Outdrive, OR a Jet, OR a Surface Drive. What are you thinking about?

[FAST FRED]

The best advantages of the drive is,

the shaft is quite short from the thrust bearing out , so replacement is cheaper.

And the engine can be on far softer mounts for a smoother quieter ride.

And of course an engine change is easy as no difficult shaft alignment is needed .

FF