What is the difference between I/O and inboard boats?

Question

Right now I have an Inboard/Outboard boat. I understand the basic difference (I/O or stern drive has a lower unit, inboard has propeller connected directly to shaft.) What is the difference in terms of performance? We are water-skiiers but also just recreational boaters. Which one works better in shallow waters? At slow speeds? Better accleration? More efficient? I'm trying to decide between I/O and inboard for a new boat-bowrider, or deck boat probably. Any suggestions?

Answer 1

Some of the inboard boats use a propeller that is on a shaft the extends from the bottom of the boat.  Turning is done with a rudder.  These are OK if you are never going to run your boat aground or go through shallow water.  

With an I/O you can raise the prop to more easily go through shallow water.  In addition, the I/O can be trimmed up or down to get the best performance when the passenger weight distribution in the boat changes or the water condition changes.  In addition one can attach wings to the de-cavitation plates on the lower unit and further increase performance.  The wings also increase handling ability at very slow speeds.  I have never seen a boat with a direct connected prop that can match the overall capability of an I/O.

Answer 2

People in my area consider I/Os to be the worst of both worlds.

Inboards are great because you have a full transom and don't have to worry about swimmers or fishing lines getting caught in your running gear. They also have a more balanced weight distribution.

Outboards a great because of the interchangability. Blow it up? Just unbolt it and drop it in your yard. A used motor is generally cheaper than a replacement inboard engine. And you can trim your outboard up to get it out of the water so it doesn't foul up.

However, I/Os have all the maintenance concerns of an inboard, with seacocks and intake risers to replace, and then you have a lower unit that's always in the water corroding, getting covered in barnacles. Furthermore, you have a rubber bellows that you hope doesn't fail and sink your boat.

You couldn't GIVE me an I/O.

Answer 3

A straight inboard has propeller shafts going through the hull, and they have a separate rudder.  Look at a Ski Nautique or a similar ski boat, and you'll see what I mean.

Answer 4

i would prefer a outboard or i/o for skiing. with a i/o u have great turning radius going forward and good steering when going in reverse. the inboard is a good boat for crusing or fishing cause u dont have the hump in the middle of ur deck. hope this helps u decide.

Answer 5

for the water sports, you are better with an inboard motor. it is much safer because your gear is under the boat and not at the back of the boat where you would get on and off the swim platform. you will notice that an inboard is a little more difficult to steer in reverse but other than that... go inboard... we run a Centurion and wouldn't run any other boat!!

Happy Boating!!

Answer 6

A true inboard is quite a bit more maneuverable than an I/O.In my honest opinion the inboard  wins hands down in all categories but the shallow water one.The I/O drive can be trimmed up whereas your stuck with what you've got with an inboard.The power to get a skier up is amazing with an inboard.

God Bless.