Jet Boats vs Outboards and IOs

[Chris1956]

Re: Jet Boats vs Outboards and IOs

Nice article. The spec sheet (picture 3) reports that the OB has a higher top speed, than the jet, with 100 less HP. The weight is about the same between the two (60# more for the jet), so I consider it an apples to apples comparison. The OB has 45% better fuel mileage at cruising speed, and is a bit slower to accelerate. The OB model was better than the jet in all the categories tested, except acceleration. The OB lost top speed to the I/O with 70 more HP, by .3 MPH.

The stats tell me that the OB powerplant is still more efficient than the jet. The difference between the OB and the I/O is less clear cut, since the weight is so different.

Of course it begs the question.."what would the OB model do with a 225HP Merc 4 cycle or Optimax?"

 

[RotaryRacer]

Re: Jet Boats vs Outboards and IOs

I think the point though is that even with "only" a 150 hp engine the OB powered boat performed on par with the other drive systems. This test was for comparable boats with similar performance characteristics. I believe the OB boat is only rated for a max of 150 also. But as the results show there is no need for more power to get a good performer that with a good prop and light load can hit 50 MPH. Note the as tested load includes full fuel and 700 lbs of passengers. That same hull with a 225 HP OB could be a 60 MPH boat. Faster than any "entry" level boat really needs to be.

 

[haulnazz15]

Re: Jet Boats vs Outboards and IOs

Of course it begs the question.."what would the OB model do with a 225HP Merc 4 cycle or Optimax?"

Same thought I had. Of course, the issue becomes a bit more complex as you get into larger boats where the outboard HP becomes limited (without going into 350HP+ outboards or twin engines). The weight disadvantage of an I/O starts to equalize when you are talking about a single 420HP V8, vs a 300HP Merc hanging off of the back, or having to run twin 200HP jets.

 

[Jetboaters]

Re: Jet Boats vs Outboards and IOs

Great discussion and got rid of a tiny bit of the mis-information around jet boats. I agree, would have been a better comparison to have put a 225OB on the comparison boat....I wonder if they chose based on price point? As I said at the start...every boat has it's pluses and minuses. The outboard doesn't do well in terms of layout for water sports, but is the only one of the 3 that can get its running gear out of the water without a lift...

Jets are awesome for acceleration, handling (at speed) and safety. Not good at top speed MPH or low speed handling and middling in fuel economy (for 24' boats).

 

[haulnazz15]

Re: Jet Boats vs Outboards and IOs

A Jet Drive is a big plus for Wake-Surfing where the rider is sometimes only 3 feet behind the Boat and could fall into a prop.

Also wanted to comment on this. Most water sports enthusiasts dislike jet-propulsion because of the turbulence it creates from the operation of the jet itself. It creates a very rough/hard surface from the spray coming out of the nozzle for wake boarding/wake surfing. Sure, there's no prop to fall on, but it's not a desirable wake which is why inboards rule the roost. I suppose it's a much cheaper alternative to buying an inboard if you want to wake surf, but I don't consider the two boats comparable in that regard.

Also, jet boats, having no rudder by design, are terrible at tracking straight when you have a loaded line from a slalom skier or wakeboarder. It's very a disconcerting feeling to a skier to be pulling on a rope that starts to "give".

 

[H20Rat]

Re: Jet Boats vs Outboards and IOs

Excellent reference, RotaryRacer. I'm a bit surprised by the use of the 150HP outboard in the comparison, simply because it's 100HP less than the jet, and 70HP less than the I/O.

One thing nobody has brought up... Outboards are rated at the prop. Inboards (including the jets we are talking here, not jet outboards) are rated at the crankshaft. End result is that the outboard number is some percentage, maybe 10-15% or maybe a little more, less than what the actual motor puts out. A 150hp outboard might actually be a 180 to 200hp engine.

Good example is my 175hp sportjet. It is nearly part for part identical (except for the crank itself) with the v6 150 merc outboards. So essentially those are prop rated at 150hp, with a 175hp powerhead.

 

[Sharp Shooter]

Re: Jet Boats vs Outboards and IOs

All in all it's tough to beat the overall package of an outboard unless you're talking over 150 mph which won't be the case on this site.

 

[haulnazz15]

Re: Jet Boats vs Outboards and IOs

All in all it's tough to beat the overall package of an outboard unless you're talking over 150 mph which won't be the case on this site.

It's all dependent on a myriad of things. If you like a sunpad or full swim platform, outboards don't work well. From a cost standpoint, twin 300HP SBC's are almost as cheap as a single 300HP O/B, especially at replacement time. Neither I/O or O/B is a great option if rocky, shallow-water operation is the end goal. There are pros/cons to every drive design, it just depends on what you're using it for and what you're willing to sacrifice.

 

[thumpar]

Re: Jet Boats vs Outboards and IOs

It's all dependent on a myriad of things. If you like a sunpad or full swim platform, outboards don't work well. From a cost standpoint, twin 300HP SBC's are almost as cheap as a single 300HP O/B, especially at replacement time. Neither I/O or O/B is a great option if rocky, shallow-water operation is the end goal. There are pros/cons to every drive design, it just depends on what you're using it for and what you're willing to sacrifice.

I agree. Every style his is pluses and minuses. For us the I/O with sunpad fits perfect. We pull tubes but most of the day is spent sitting with bow anchored and the aft tied to the beach. The rear is used for entry and exit. The full length sunpad and swim platform work best for us.

 

[Sharp Shooter]

Re: Jet Boats vs Outboards and IOs

It's all dependent on a myriad of things. If you like a sunpad or full swim platform, outboards don't work well. From a cost standpoint, twin 300HP SBC's are almost as cheap as a single 300HP O/B, especially at replacement time. Neither I/O or O/B is a great option if rocky, shallow-water operation is the end goal. There are pros/cons to every drive design, it just depends on what you're using it for and what you're willing to sacrifice.

That's definitely true. We all have different needs and wants when it comes to our boating.

 

[H20Rat]

Re: Jet Boats vs Outboards and IOs

All in all it's tough to beat the overall package of an outboard unless you're talking over 150 mph which won't be the case on this site.

EVERY boat is a compromise. I do alot of wakeboarding. Outboards are laughed off the lake for wakeboarding, they are great for pulling the kids around on a tube but fail in so many areas for watersports. And try wakesurfing being an outboard. Not going to happen unless you like missing limbs. (I/O's are just as bad, this is where true inboards shine.)

 

[Sharp Shooter]

Re: Jet Boats vs Outboards and IOs

You're preaching to the choir my man. I started skiing at age 5 (1973) behind this inboard. Throughout my lifetime I've skiied surfed and boarded behind just about every type of boat imaginable at one time or another.

And just to stir the pot, check this out.
Mastercraft powerstar ski boat. Strong enough fro barefooting.

 

[thumpar]

Re: Jet Boats vs Outboards and IOs

You're preaching to the choir my man. I started skiing at age 5 (1973) behind this inboard. Throughout my lifetime I've skiied surfed and boarded behind just about every type of boat imaginable at one time or another.

And just to stir the pot, check this out.
Mastercraft powerstar ski boat. Strong enough fro barefooting.

Guess what Mastercraft doesn't make anymore.

 

[Sharp Shooter]

Re: Jet Boats vs Outboards and IOs

Guess what Mastercraft doesn't make anymore.

Mastercraft sold the Barefoot 200 and powerstar 200 for at least 12 years. Probably dropped the line with the drop of barefooters. Regardless, the power to pull up a wakeboarder was definitely there.

 

[thumpar]

Re: Jet Boats vs Outboards and IOs

Mastercraft sold the Barefoot 200 and powerstar 200 for at least 12 years. Probably dropped the line with the drop of barefooters. Regardless, the power to pull up a wakeboarder was definitely there.

Power is definitely the issue with wakeboarding with that. I think it is the lack of a good wake.