2013, the year of the jet drive?

[jestor68]

Re: 2013, the year of the jet drive?

No, I think it's that cost thing . . . They make a BUNCH of these coupled with the same pump. One makes little boat go, two make bigger boat go


That doesn't bother me at all. They know how to build them to spin faster, and pleasure craft just don't wear out if maintained.

You forgot the smiley face for that second remark. It had me laughing! Motors that don't wear faster when run 7200 rpm! :laugh:

 

[smokeonthewater]

Re: 2013, the year of the jet drive?

Ok fine.. 2013 can be the year of the jetboat....




only 10 more months and we can get back to normal

 

[QC]

Re: 2013, the year of the jet drive?

You forgot the smiley face for that second remark. It had me laughing! Motors that don't wear faster when run 7200 rpm! :laugh:

No. I agree they wear faster, I just don't think the typical pleasure boater will wear one out. Commercial? Absolutely. Pleasure, they break before they wear out.

 

[spoilsofwar]

Re: 2013, the year of the jet drive?

I'm guessing you wouldn't have any repairs at all if you get a new one every 2-3 years.

I didn't lay it all out, but we're talking about Sea-Doo's as old as a 1990, two 1995's and a 1997. None of them were new or even close to new when I got my hands on them. And three were owned over the same time frame.

The old two stroke, twin cylinder Rotax's, and their included jet drives, were very, very reliable machines IMO. I have no experience with the new four stroke stuff. Having a kid and my wife not being into riding got me out of the PWC world and into boats. No regrets there I will take my Stingray over any PWC, or even two.

 

[Toddavid]

Re: 2013, the year of the jet drive?

Nobody seems to have mentioned the noise issue with jet boats? All the ones I have been on have engines that are quite loud at cruising speed.

And they are quite light for their size, too.

A good buddy who has a Yamaha SX230 came out on my Chap and without prompting commented how my boat was like a Cadillac and his was like a Miata. Mine was quiet and soft riding and his was loud and harsh riding.

And his wife had grown tired of coming out on their boat because of the sound volume and ride. Oh, and the lack of head, too.

 

[OrangeTJ]

Re: 2013, the year of the jet drive?

I'll agree that they're somewhat loud onboard. That can be mitigated but not eliminated, at least as far as I can tell. It doesn't bother me at all, but that is likely because I have spent years riding motorcycles and have grown accustomed to loud (i.e. I've lost some hearing!). My wife and kids have never mentioned that the boat seems loud to them, but then they don't have a whole lot of experience with other boats. Also, I'm not surprised that a 25 foot Chap would ride softer than a 23 foot Yamaha! There are tradeoffs in either direction (noise vs. acceleration - smooth ride vs. maneuverability/nimbleness, and so on). What matters is getting the boat that does what you want a boat to do and getting out on the water to enjoy it!

 

[agallant80]

Re: 2013, the year of the jet drive?

I don't see any issues with the Jet Drive. Technology evolves, at this point there may be some early adopters due to the fact that some buyers don't know anything about jet drives or out drives and just buy the boat that they like and some people buy them because they are early adopters and see the benefits of the technology despite some issues (fuel, cleaning out the drives etc). The technology will evolve and improve over time untill it may be the standard some day. The way I see it ate:
+
no props to ding
no outdrives to hit something
being able to go to shallower watter
dual motors in most cases

-
People don't know allot about them now
You have to clean them out
not allot of after market parts

I am sure there is more on both the + and - side. But look at it this way. Its a good thing the new technology will evolve and replace the existing technology or it will force the existing technology to innovate and add in the features that the jet drives have that the out drives don't have.

 

[QC]

Re: 2013, the year of the jet drive?

The silly thing is that Jets are not new, and you don't have to buy twin, hi revving engines. What we have are PWC companies moving towards boats. Use the same stuff. You can have the same GM based engines spinning jet drives. They are very popular in the Northwest and used to be popular on the Colorado river here. You can still order them new. EFI etc. More efficient pumps have definitely evolved, and they are also common on large ships. The problem with these threads is they are typically started regarding the smaller PWC based products, yet answers and questions push out into the other areas. Jet's are one thing, boats with jets are another and vary greatly.

 

[emilsr]

Re: 2013, the year of the jet drive?

No. I agree they wear faster, I just don't think the typical pleasure boater will wear one out. Commercial? Absolutely. Pleasure, they break before they wear out.

I've got to respectfully disagree there. The high revving engines are good for about 500 hours and that's it. If you boat much at all you're going to have to rebuild/repower every 5-6 years and that's a VERY expensive proposition. CAN they last longer? Sure, but in comparison to automotive based power or outboards they have a comparatively short service life.

I know a few folks who have worn them out. They all loved the boats until the repair bills came in.

Agreed though that the Yammie boats and the like are just the tip of the jet boat iceberg. Back to the original thread subject; I still say the market is moving in that direction.

 

[QC]

Re: 2013, the year of the jet drive?

I've got to respectfully disagree there. The high revving engines are good for about 500 hours and that's it.

And I am going to have to respectfully ask you for data

Maybe we should define wear out vs. break. What makes them not good at 500 hours?

I have nothing to base my comments on other than engines have been my career. Definitely not small high revving engines though. I just generally accept most large companies ability to make good stuff. Trust me, I really understand the exceptions. Have the scars.

 

[OrangeTJ]

Re: 2013, the year of the jet drive?

I've got to respectfully disagree there. The high revving engines are good for about 500 hours and that's it. If you boat much at all you're going to have to rebuild/repower every 5-6 years and that's a VERY expensive proposition. CAN they last longer? Sure, but in comparison to automotive based power or outboards they have a comparatively short service life.

I know a few folks who have worn them out. They all loved the boats until the repair bills came in.

Agreed though that the Yammie boats and the like are just the tip of the jet boat iceberg. Back to the original thread subject; I still say the market is moving in that direction.

Have a source on that 500 hours? That certainly doesn't align with the anecdotal reports of people who have owned these or what I've heard from a couple of guys who rent out Yamaha waverunners that use the same powerplants. You talking about 2 stroke or 4 stroke engines? Heck, what I "heard" from boat dealerships when we were out looking at all sorts of boats was that the anticipated time between rebuilds or major top-end work on the car-based engines was 500 - 600 hours. I do realize that just because dealers said it, that does not make it true. OTOH, what benefit would they get from short-selling their products?

 

[Mischief Managed]

Re: 2013, the year of the jet drive?

I've got to respectfully disagree there. The high revving engines are good for about 500 hours and that's it. If you boat much at all you're going to have to rebuild/repower every 5-6 years and that's a VERY expensive proposition. CAN they last longer? Sure, but in comparison to automotive based power or outboards they have a comparatively short service life.

I know a few folks who have worn them out. They all loved the boats until the repair bills came in.

Agreed though that the Yammie boats and the like are just the tip of the jet boat iceberg. Back to the original thread subject; I still say the market is moving in that direction.

I won't be buying a jet any time soon, but I think the latest Yamaha 1.8 liter engine is a good compromise between displacement and high revs. I would expect it to last substantially longer than 500 hours. It's probably very similar to the 2ZZ engines Yamaha makes for Toyota and Lotus.

 

[Toddavid]

Re: 2013, the year of the jet drive?

The silly thing is that Jets are not new, and you don't have to buy twin, hi revving engines. What we have are PWC companies moving towards boats. Use the same stuff. You can have the same GM based engines spinning jet drives. They are very popular in the Northwest and used to be popular on the Colorado river here. You can still order them new. EFI etc. More efficient pumps have definitely evolved, and they are also common on large ships. The problem with these threads is they are typically started regarding the smaller PWC based products, yet answers and questions push out into the other areas. Jet's are one thing, boats with jets are another and vary greatly.

Is the twin engine an attempt to address the difficulty in directional control? Twin propulsion, better low speed control? Water propulsion is notoriously less effective at low flow rates.

And when splitting into two engines, higher revving means more horsepower per cubic inch of deck space being eaten up (engines can have a smaller footprint).

This is another apparently effective add on for jet boats to help with reverse control (something that is seriously lacking in stock form, I have heard):

Photos

 

[OrangeTJ]

Re: 2013, the year of the jet drive?

If I generally run an engine with an 8300 rpm rev limit at 6K rpm (normal cruise for us in our SX210), keeping in mind that this same engine architecture supports a 10K+ redline with different cams and engine control, am I working it significantly harder relative to it's capability than a guy running at 3K rpm with an engine that revs out at 5K rpm. I wouldn't expect any engine to last a long, long time if continuously run at redline, whether it's automotively based or not. Hence, I don't cruise around at the rev limit all the time, just like I'm sure most folks with boats powered by small block V8s don't.

 

[QC]

Re: 2013, the year of the jet drive?

Is the twin engine an attempt to address the difficulty in directional control?

Clearly a benefit, but I don't think that is why. I think the primary reason is that's what they have to sell.

I totally agree that higher rev generally equals less displacement and weight for the same output. I have been posting in regards to that for years. I do not subscribe to no replacement for displacement; of course there is: more air. You can get more air with RPM, turbocharger or supercharger. None of those is necessarily bad by itself. And the silliness of discussing reliability and heavy duty regarding forced induction stops at pretty much all diesels. The air technology is no different.

 

[Toddavid]

Re: 2013, the year of the jet drive?

Clearly a benefit, but I don't think that is why. I think the primary reason is that's what they have to sell.

Um. Yep. Totally forgot about that. Yamaha = motorcycles. :embarassed:

 

[emilsr]

Re: 2013, the year of the jet drive?

And I am going to have to respectfully ask you for data

Maybe we should define wear out vs. break. What makes them not good at 500 hours?

I have nothing to base my comments on other than engines have been my career. Definitely not small high revving engines though. I just generally accept most large companies ability to make good stuff. Trust me, I really understand the exceptions. Have the scars.

You mean I have to prove it? :facepalm:

I have no empirical data, only anecdotal, and not with the Yammie:

BIL had a total of 3 of those Sea Doo boats as dingies for their cruiser. All 3 started losing power around 400-500 hours. I don't remember exactly what was going on internally, only that they needed expensive rebuilds.

Since he isn't exactly a maintenance whiz, I posed the same question to some of my neighbors in Missouri who also had those boats (was thinking about getting one to run around our cove). They all said the same thing, as did our marina/mechanic. "500 hour boats" Same with all the 2-stroke jet fleas that our friend with the rental place owned.

I also vaguely remember from back in my aviation days the Rotax engines had a comparatively short TBO, but that was a long time ago. Things may have changed.

To be fair to Yamaha, we have some friends in KY who are on their 3d and they love 'em. The first was replaced because they went bigger. The second was replaced at about the 900hr point for no particular reason other than they wanted a new one.....so the 500 hour comment isn't "fair and balanced" for jet boats in general.

 

[blackhawk180]

Re: 2013, the year of the jet drive?

First jet I see offshore, I'll let you know. Not sure why... no weeds, no debris and no bottom to worry about but no jets. Where I fish it looks like about 70% dual outboards (prop). The rest are big OB singles or I/O.... and maybe a couple diesel I only.
When I fish the rivers, I see a lot of jets and can't argue with the skinny water or maneuverability of them. But I'm fishing, not zooming around dragging tubes or such. Even the jets run kickers to troll with so I guess it's what you like to do, where you like to do it and what fits your needs.

 

[OrangeTJ]

Re: 2013, the year of the jet drive?

I, too, have "heard" that the Sea Doo boats powerplants tended to run into trouble relatively early. Don't know if it's true, but it is one of the reasons I went with a Yamaha.

 

[Part-time]

Re: 2013, the year of the jet drive?

Curious. What does Yamaha do to make their low speed maneuverability better? I haven't driven any new jet boat.

I had an 18' sidewinder SS with a 455 olds and berkley jet drive and could out manuver any twin screw I/O.
I did have a high idle switch that bumped my rpm's up to 1,100 to get more water pressure to manuver while docking.
I could just immagine what could be done with twins and modern technologie.

The other thing left out is that the larger Bowriders are all using twins. They have a total of 420 Horsepower and struggle to get 51 MPH. I have a 24 foot bowrider (bigger by modern standards) and I run 57 MPH with 320 bhp.
I find it interesting that it takes twin super charged jets to equal the performance of a single I/O. Maybe it's that efficiency thing.

Try loading that twin engin jet and your single I/O to maximum capacities and then compare numbers again....
The jet drive is using "X" amout of hp to produce "X" amount pressure (thrust).
If you run a jet at a given rpm you will use the exact same gallons per hour loaded or empty.
As you load your boat your engine will work harder and your gallons/hour goes down.