Questions on general inboard boat design...

[IDBoating]

Of course you have less turbulence, you're only going about 5 Mph.

He likes 20-22 MPH, which is what we would have been driving in that sequence. He learned at 18 MPH when he was 4YO but didn't stay there very long. {grin}

[Guapo]

The MC X-35 is self bailing (spelling?). Before I bought my RZ2 last year, I looked at the X-35 and liked that feature. Not sure what method it uses, but there's one wake board boat that has it.

[embo]

Ok guys...somehow I am missing how the "submarine" boat does what it does. It appears to just hit a low spot in the water and then the bow dives...what is actually happening there? ?

Love the vid by the way!

[chpthril]

The MC X-35 is self bailing (spelling?). Before I bought my RZ2 last year, I looked at the X-35 and liked that feature. Not sure what method it uses, but there's one wake board boat that has it.

the Saltwater X-35 is designed to put you in the spotlight with an array of other impressive features and amenities that definitely help you rise above it all. Such as a smoother ride from the X-35's deeper, self-bailing hull

Hmmm

[Ewok]

Ok guys...somehow I am missing how the "submarine" boat does what it does. It appears to just hit a low spot in the water and then the bow dives...what is actually happening there? ?

Love the vid by the way!

It looks like the driver starts a hard turn and then puts the boat in reverse, like a giant speed brake. Similar to what the jet boat does when it puts it's reverse scoopers in the water. The last video is just a very hard power turn, like they do in waterski shows, only done properly.

[embo]

Wow!! I am not sure whether to laugh or just shake my head in amazement if I saw this in person. Interesting way to wash out the inside of the boat.

The turn looks pretty cool. If I tried that move, my steering cable and throttle would break just at the wrong moment and I would be front and center right up next to the camera.

Thanks for telling me how that was done.

[IDBoating]

Similar to what the jet boat does when it puts it's reverse scoopers in the water.

To be complete: You have to lower the thrust reverser, and then ramp up the engine. It's exactly what happens when a jetliner lands... they reverse the thrust and ramp up the engines to slow down the plane.

On a jetboat, it dives the bow and causes a huge wave to build in front of the boat, which then collapses by gravity. By modulating the throttle, a good driver can keep the wave in front of the boat (very little water in the boat), move forward so that the wave collapses on the passengers in front, or keep the boat moving so that the wave collapses along the length of the boat and drenches everyone.

We call it the "braking maneuver" and it's a favorite when we have new teenagers in the boat. We have them sit in the rear-facing bow seats so they never realize the wave is there until it is too late. The passengers in back get a nice show but stay relatively dry (except for their feet).

By the way, having brakes has saved us a couple of times from idiots in other boats who weren't paying attention. So this "feature" has benefits beyond just being silly.

[talltigeguy]

The MC X-35 is self bailing (spelling?). Before I bought my RZ2 last year, I looked at the X-35 and liked that feature. Not sure what method it uses, but there's one wake board boat that has it.

There are 2 ports that are in the main cabin area and they drain downward right to 2 openings just below the swim platform. So any large amounts of water that get into the main cabin area run right down to those openings and back into the lake. I am sure that the cabin area is not waterproof, so I would still expect plenty of water to drip into the bilge from above the storage compartments and such. But it would be super nice for one of those uh, oh, moments when you screw up and take a big roller over the bow. Notice the drains right below the swim platform level. Or it would be very good to have on very high seas when taking some over the bow happens no matter how you drive it. Having been in the X35, I don't think it would be possible to get rollers over the bow except in very rare circumstances. Now my 45 is another story.

[boatwakes]

Berkely/Dominator/Jaquzzi jet systems are not hydrodynamically efficient at lower rpms(approx 1000-2800 depending on vessel displacement). They are directly coupled to the engine so they turn at 1:1 with the motor but are constantly trying to overcome the weight of the vessel as well as avoid cavitation while getting up on plane. Once up to speed and on plane, they become very efficient as the water intake is forced into accepting water through the bottom of the boat.
An example: I built a 1969 19' hallett with a 455 olds (punched out to 468). It would burn 2 gallons an hour at 26 mph turning 2400rpms but at 1900 rpms it was doing 13mph and burning 3 times as much, not quite on plane and sucking down the fuel. And at 4000 rpms, it was doing 63mph and burning 6 gph, nearly the same as cruising.
I'm 6'7" 240lbs and tried wakeboarding behind it once...needless to say, the vessel changed course about 45 degrees and we never tried that again. I'm also a 100ton USCG licensed captain, own several boats, run a commercial towboat for Vessel Assist and my own company, have side-tied hundreds of boats and put them in their slips under tow, and I agree that any single engine inboard is more difficult to manuver than most other vessels if you're not aware of its driving characteristics.
BTW WAboating, I used to own a jet ski rental company and we had 2 of the same "jet" boats that you have. If you have the merc (M2 Jet) power head, a word of warning: Where the power head meets the hull WILL crack and leak, potentially sinking your boat. It happened to some renters in one of ours and the motor actually fell halfway thru the hull. The reason for this is: there is NO stress relief for the thrust of the engine/jet thru the hull. Instead of being transferred through shock absorbing rubber engine mounts into the stringers of the boat, thrust is transferred directly from the vibrating, shaking engine/Jet drive assembly into the NON-REINFORCED 3/16" chip-shot fiberglass motor box surrounding the engine. Older jet boats with big blocks had reinforcement throughout every thrust point area as well as thicker glass and case materials, the boat you have does not.
Inboards: straightforward and reliable service, easy to diagnose, common problems avoidable with proper maintenance, easy parts availability, efficient and proven.
Jets: straighforward and reliable service, easy to diagnose, common problems not avoidable with maintenance, unit needs to be removed for any type of service, no true neutral or reverse, efficient only at and above cruising speeds, proven in commercial craft designed for specific applications.

Note: Cummins/Mercruiser's Zeus Pods...semi efficient but stupid, I could go on for days. Volvo's IPS drives...efficient but stupid, functional for manuverability in tight quarters (i.e. can make even the biggest donkey look like a rockstar when parking at Catalina Island) but still, I could go on for weeks.

And in closing, if you'd like, I would entertain the idea to undertake a design and build effort to produce a running prototype towboat with a jet drive system that followed the same driveline as an inboard "just to see" how it would do.

[Guapo]

There are 2 ports that are in the main cabin area and they drain downward right to 2 openings just below the swim platform. So any large amounts of water that get into the main cabin area run right down to those openings and back into the lake. I am sure that the cabin area is not waterproof, so I would still expect plenty of water to drip into the bilge from above the storage compartments and such. But it would be super nice for one of those uh, oh, moments when you screw up and take a big roller over the bow. Notice the drains right below the swim platform level. Or it would be very good to have on very high seas when taking some over the bow happens no matter how you drive it. Having been in the X35, I don't think it would be possible to get rollers over the bow except in very rare circumstances. Now my 45 is another story.

Tall...thanks for the pic and the explanation. I couldn't find on MC's site where it showed where it drained. Just curious...how did you like the X35?

[IDBoating]

VERY useful info, thanks for sharing!

If you have the merc (M2 Jet) power head, a word of warning: Where the power head meets the hull WILL crack and leak, potentially sinking your boat.

You're correct, and I'm aware of this. I monitor that area of the hull carefully. However, I believe Seadoo beefed up the hull in that area after this problem occurred a few times. I've heard of it happening to much older boats but I've never heard of a single instance in later ones, and I'm plugged in rather tightly to the jetboat community and lots of Mercury M2 owners.

Jets: no true neutral or reverse

True, the impeller is always spinning, but the thrust reverser can balance forward and reverse thrust to yield no movement. Frankly, that's the single best feature of a jet - leave the engine at a constant RPM and feather the thrust reverser to slightly vary the forward/reverse ratio. Just like setting an aircraft engine at a constant RPM and varying the feathering of the prop.

And in closing, if you'd like, I would entertain the idea to undertake a design and build effort to produce a running prototype towboat with a jet drive system that followed the same driveline as an inboard "just to see" how it would do.

I'd love to do that. Wish I had the wallet to support my interests! {grin}

[dom w. forte]

You didnt comment about the fuel economy?

[IDBoating]

You didnt comment about the fuel economy?

Based on his comments, I'll hazard a guess that the jet has poorer fuel economy at lower speeds and higher economy at higher speeds. Of course, the definition of "higher speed" in this context is unclear... is he talking about impeller RPM's? Flow rate through the pump? Hull speed?

Many of those factors would be determined by the design goal; you would optimize based upon the nominal operating conditions expected for the watercraft in its intended application. I other words, you'd design differently for a tugboat than for a jetski than for a towboat. (True for open propped versions of those craft, as well.)