thoughts on Jet drive boats

[karatejoe]

Has anyone ever owned a Jet drive boat?
I hear bad things about them but never from anyone that has ever owned one.
Im wanting to know how well they work in a saltwater application.
Can they really be more costly than an I/O ?

 

[H20Rat]

Re: thoughts on Jet drive boats

first, what kind of jet drive? big block connected to a berkeley or a sportjet/yamaha/seadoo type setup?

the bad: somewhat higher fuel consumption. Don't believe everything you hear, outboard jets are the worst, 30% compared to a prop. Inboard jets are substantially better.

the good: much lower part count/complexity. no transmission or shifting gears. Easier maintenance in most cases compared to an inboard engine. Vastly better handling once you learn how to drive a jet. (its different, a little tougher but once you get the hang of it you can do things in a jet that are 100% impossible in a prop craft)

There are all kinds of other things in the good category I'm leaving out, but search around on here...


Salt... Just don't leave them in salt water, need to be flushed like any other craft.


Costly? In which way? Fuel is certainly going to cost you more. Maintenance will be less. I've owned numerous jets, I use them on a river that has frequent sand bars, and its nice to skim over the top while other people are pushing. (more or less if I can see water I can drive there, draft while running is 2 or 3 inches max) If i didn't have that specific need, I probably wouldn't have a jet.

 

[Capt'n Chris]

Re: thoughts on Jet drive boats

Squirt boats! What bad things have you heard? Who said them and how poorly were their jet boats maintained? All boats are costly. So are race horses and swimming pools.The better the care, the more they cost.

 

[evilnss]

Re: thoughts on Jet drive boats

I actually just sold my seadoo sportsters to buy my bayliner capri.

The Jetboat is a blast! fun and quick on the water, turns on a dime, and they are a PIECE OF CAKE TO WORK ON! Love it!

 

[jafo9]

Re: thoughts on Jet drive boats

you still have to be careful what you run over. the impeller intake can suck stuff from the bottom up to a few feet down. rocks will damage the impeller and sleeve. sand is obviously harmful as well. from what i understand, you are actually better off on plane going over shallows than going slowly on a jet propelled craft with a PWC style intake.

you also have to consider that most of these beasties have 2 motors (seadoo and yamaha) and that doubles the cost of maintenance.

i'm not trying to change your mind, i'd consider one too. biggest plus for me is the safety factor of not having a prop for swimmers to come in contact with. i wouldn't get any of the older 2 stroke models though. i've got 2 strokes on my PWC's and they are pretty maintenance intensive. particularly getting to the carbs on the yamahas. don't even get me started on my pos seadoo.

 

[H20Rat]

Re: thoughts on Jet drive boats

from what i understand, you are actually better off on plane going over shallows than going slowly on a jet propelled craft with a PWC style intake.

don't even get me started on my pos seadoo.

plane... yep, exactly. MOST of the rocks/sand that go through a jet are from startup, trying to get on plane. On plane, what usually happens is that when you pass over a rock/sand, it will get lifted up, but by the time it actually makes it to your intake, you are far enough forward it smacks into the ride plate instead of getting sucked in. (I've got some decent gouges on my ride plate, but only a tiny nick or two on the impeller)

I've had a '97 gsx seadoo for a couple years now, haven't had a single problem or done any maintenance other than changing oil. (a little over 200 hours on the clock) Like every engine powered craft, some are alot more finicky than others. Seadoo 787 engines are rock solid!

 

[Hogger]

Re: thoughts on Jet drive boats

I've had a SeaDoo Speedster that we ran 100% in salt, and never had any problems, just flush the engines right away when you pull it out.
And I just sold my Sea Ray F-16 with the Mercury 175. That thing was pretty bad on gas, but I'd have to disagree with jafo9, the Mercury sportjet 175 is probably one of the best 2-stroke engines on older boats. They are a powerhouse and a work horse. Parts are readily available and cheap, of course it depends on how it was treated and maintained. If I was looking for a jet boat, I would first look for one with a Mercury sportjet, preferably the 175, or the new 240. The 90 and 120's were pretty weak.

 

[haulnazz15]

Re: thoughts on Jet drive boats

Like was said, they will be worse on gas, especially with twin engines. The slow-speed handling is worse (due to lack of rudder), but it's not a huge deal. Shallow water can make you pick stuff up, but it can hurt an I/O just as bad when you hit bottom.

One major thing to worry about is running over the ski/tube rope on a jet engine, as that impeller/shaft is rotating just as fast as the engine, so it winds up that ski rope in a hurry! You also won't likely be able to remove the rope without getting it back on the trailer since it's all underwater and requires tool to remove the impeller grate. On an I/O, you just have to raise the drive and cut the rope off of the prop or simply remove the prop, which both can be done without being underwater.

My 98 Kawasaki JetSki 1100STX has been absolutley ZERO maintenance for the past 8+ years. We change spark plugs each year, and add sta-bil to the gas in when we put it up. I did have the carbs cleaned/tuned when we got it (triple mikunis) at the cost of $100 total to fix a rich idle. So they really are extremely low maintenance.

I will stick with the I/O's just due to performance limitations and fuel usage of the jet-style engines, but those new Yamaha twin-engine boats are slick. I guess I don't have any fear about the outdrive/prop and swimmers, they can't get hurt if it isn't running/in gear so unless they manage to jump off the deck onto the unit (which is visible anyway) I don't see that as an advantage.

 

[H20Rat]

Re: thoughts on Jet drive boats

And I just sold my Sea Ray F-16 with the Mercury 175. That thing was pretty bad on gas, but I'd have to disagree with jafo9, the Mercury sportjet 175 is probably one of the best 2-stroke engines on older boats. They are a powerhouse and a work horse. Parts are readily available and cheap, of course it depends on how it was treated and maintained. If I was looking for a jet boat, I would first look for one with a Mercury sportjet, preferably the 175, or the new 240. The 90 and 120's were pretty weak.

I've got a SJ 175 powered jetboat right now. The engine is rock solid, it is the 2.5L outboard powerhead that merc used in a ton of engines. (175 is the smallest engine to use that block, so its well built for the displacement)

 

[hubbard53]

Re: thoughts on Jet drive boats

One major thing to worry about is running over the ski/tube rope on a jet engine, as that impeller/shaft is rotating just as fast as the engine, so it winds up that ski rope in a hurry! You also won't likely be able to remove the rope without getting it back on the trailer since it's all underwater and requires tool to remove the impeller grate. On an I/O, you just have to raise the drive and cut the rope off of the prop or simply remove the prop, which both can be done without being underwater.

I will stick with the I/O's just due to performance limitations and fuel usage of the jet-style engines, but those new Yamaha twin-engine boats are slick. I guess I don't have any fear about the outdrive/prop and swimmers, they can't get hurt if it isn't running/in gear so unless they manage to jump off the deck onto the unit (which is visible anyway) I don't see that as an advantage.

I have one of those twin engine yamahas...

what's cool about them is that each impellar has a clean out port accessbile from the swin deck. If you do get a line in the impellar, pop the port and pull it out. Easy.

Fuel cost isnt bad for me but i've never had an IO so cannot compare. From what I've ready, it is just slightly (very slightly) more gas guzzling than a conventional IO.

Maintenance was the biggest factor for me - i change the oil on two four stroke fuel-injected engines each season. Maybe change the sparkplugs every couple seasons. Do the winterization myself. Its like maintaining a modern car.

Jetboats arent for everyone; you should certainly take a look for yourself... go to www.yamahajetboaters.com for more info

 

[haulnazz15]

Re: thoughts on Jet drive boats

^ good info on the port, I didn't know that. I just know my roommate in college sucked up my ski rope being stupid (doing 360s) after I let go of the rope from slolam skiing. That nylon rope welded to itself from the rapid heat produced from being spun up on the impeller shaft. Needless to say it ruined the outing as I didn't have a knife on the jet ski, nor the tools to remove the intake grate.

Food for thought though . . .

 

[smclear]

Re: thoughts on Jet drive boats

The slow-speed handling is worse (due to lack of rudder), but it's not a huge deal.

Not true at all. Jet drive boats handle far better than any prop driven boat at low speeds. I can spin mine 360 degrees in it's own length and maneuver it directly sideways. You can not do that in a prop boat. They ARE tricky at first, but once learned, you can do anything.

 

[karatejoe]

Re: thoughts on Jet drive boats

Thanks for all the info. Its nice to get honest info from people that actually know. This is a great forum with good people in it.

 

[haulnazz15]

Re: thoughts on Jet drive boats

Not true at all. Jet drive boats handle far better than any prop driven boat at low speeds. I can spin mine 360 degrees in it's own length and maneuver it directly sideways. You can not do that in a prop boat. They ARE tricky at first, but once learned, you can do anything.

That hasn't been true in my experience. I have only driven the single-engine jet boats, but I found that straight line tracking at slow speeds is more difficult. They do have a tighter turn radius though.

 

[H20Rat]

Re: thoughts on Jet drive boats

That hasn't been true in my experience. I have only driven the single-engine jet boats, but I found that straight line tracking at slow speeds is more difficult. They do have a tighter turn radius though.

yep, without smart tabs, some hulls wander at slow speed. (my sugar sand heat did badly, 14.5 ft, my tango at 17 ft doesn't at all) As far as being more maneuverable though, you can do things normally reserved for a twin screw boat with thrusters! Turning on a dime, as well as sliding sideways, all things you can do.

You also have brakes with a jet boat. need to stop from 50 mph to 0 in a couple boat lengths? no problem! (you are going to get drenched while doing it, but it is possible without destroying the boat or yourself)

Jet newbies usually have a couple problems... Very little control without some throttle, delay in reaction, and your steering while reversing is backwards what a prop boat is. Just a learning curve to get used to.

 

[jfadool]

Re: thoughts on Jet drive boats

I think a lot of jet boats get a bad rep for the same reason that bayliners do. Many people buy them and do not maintain them properly. Anything (car, truck, boat, motorcycle) with proper maintenance will last for a long time.

Yes some designs are better than others, but there are very few bad designs. I love little jet boats, they are quick, fun for a few people and while I did own the black sheep of the jet boats, the rage, I did enjoy it.

My rage was a yamaha 650 jet not the OMC thing, and I did not have any problems. I have switched to a 15ft with a 70 jonny outboard. I am just more comfortable with it.

Bottom line is that there are quite a few people I know with little jet boats, most of them really enjoy them.

 

[JoLin]

Re: thoughts on Jet drive boats

Damn PWC's are everywhere, so they must work okay...

 

[jafo9]

Re: thoughts on Jet drive boats

interesting reply about hitting the brakes. i never thought of that. only one of my skis has reverse and i do use it as a brake sometimes. i've thrown some folks forward on my boat cutting the throttle too fast, i can only imagine dropping the reverse buckets and watching the passengers fly by.

another good point to mention is that the PWC type boats don't have a true neutral, they just hand the reverse bucket down a little to halt forward progress

 

[shwoop_soobie]

Re: thoughts on Jet drive boats

so there is lots of talk about the sportster type boat, but what about something like a semi v big block powered beast?

 

[ExxWhy]

Re: thoughts on Jet drive boats

My dad had a 1972 IMP 16' deep V with an Olds 455 and a Jacuzzi jet drive. Loved that boat and I don't recall any maintenance issues. Used it on Lake Erie a lot, it handled waves pretty well for a boat that size. As I recall, it wasn't the easiest to manuever at low speed. Had one heck of a hole shot though!