thrust vector spray and turning ability

[elcue]

Thanks for the info. I never heard of this that's why I'm interested. I'm amazed that this is normal. I'm considering a new boat possibly a 2018 E-series or just getting a tritoon with an outboard. I have to definitely test drive the new one and look for this if I stay with the jets.

 

[Cobra Jet Steering LLC]

It shows that you have a couple of p w c s those do the same thing if you pay attention to how well they turn to the left as opposed to the right.
As for steering I make a couple different systems that do both slow speed and high speed steering enhancements so this is no problem left or right at speed. Same for my skies once you add extra steering you can do a lot of wild things even pull 5 people in two tubes in tandem driving with no hands standing on the seat. Not that you would want to of course ! or run into the mangroves on the shore at 60 mph and turn instantly without slowing down just to show off a bit, but again not that you would want to try that or do it driving with your feet laying on your back because you can , all things that require a lot of extra steering input to accomplish , I love all that extra steering but that's just me.

 

[Matt Phillips]

I had TVs on my old 232 and after a couple of seasons, it started turning really hard to starboard as I was coming about to pick up a downed skirt. To the port was fine. The only thing I could determine was how the TVs were going from the up to down position while slowing. I found that if I cut thrust for a moment then reapplied, the boat would turn normally.

The next season I switched to Cobras and the boat then turned equally well both directions until the day I sold it a few seasons later.

This was just my observations

 

[Ronnie]

It sounds like pump loading is the same thing as/consistent with what I've read about why jet boats are more responsive turning in one direction v. The other. That is, both impellers spin to the right/clockwise ( I believe ) so the boat turns to the right more quickly than the left. Supposedly it's a torque thing. By analogy if the impeller were the main rotor on a helicopter the helicopter would turn/yaw more easily in the same direction that the main rotors are spinning, so from a top down perspective it would turn to the right more quickly if the blades are spinning clockwise and vise versa if the blades spin counter clockwise. Without a tail rotor or some system (notar) to counter the torque of the main rotor the body of a conventional (pod and boom) helicopter would spin/turn in the same direction as the main rotor. Our boats are subject to the same forces but they the impact is not as perceptible because boats are in/pushing against/have to cut through water not just air like helicopters. That's the way I understand it anyway. There are more than a few engineers and plane/helicopter pilot members on this forum that won't be shy about correcting me if I wrong.

If Yamaha could have eliminated this in the twin engine boats by simply making the engines turn in different directions why didn't they? Cost I assume but how much more could it cost to accomplish this (the blades on one of the impellers would have to be reversed as well). It's not like Yamaha is worried about pricing themselves out of the jet boat market, it seems like they raise the price a few thousand every year even when there are no major changes yet they are still the least expensive / best selling boats in their class/size. I can't think of one other brand that sells a comaprable 21' to 24' boat for less than Yamaha msrp.

 

[JetBoatPilot]

@kyle if you're experiencing mist in the cockpit you likely got an older version of the Thrust Vector XV's when you bought. We'll be glad to upgrade you to the newest version free of charge if you like. Just give me a call and I'll help you out.

 

[kyle]

@kyle if you're experiencing mist in the cockpit you likely got an older version of the Thrust Vector XV's when you bought. We'll be glad to upgrade you to the newest version free of charge if you like. Just give me a call and I'll help you out.

I bought them off the shelf at the dealer in July but wondered after the fact how old they were because the box was pretty dusty. How can I tell if it the old design? Thanks for the reply too.

 

[swatski]

If Yamaha could have eliminated this in the twin engine boats by simply making the engines turn in different directions why didn't they? Cost I assume but how much more could it cost to accomplish this (the blades on one of the impellers would have to be reversed as well).

These boats have direct drives with no gear reduction. It would not be simple, more like a whole new engine.

--

 

[kyle]

I had TVs on my old 232 and after a couple of seasons, it started turning really hard to starboard as I was coming about to pick up a downed skirt. To the port was fine. The only thing I could determine was how the TVs were going from the up to down position while slowing. I found that if I cut thrust for a moment then reapplied, the boat would turn normally.

The next season I switched to Cobras and the boat then turned equally well both directions until the day I sold it a few seasons later.

This was just my observations

You explained my exact concern and issue I am experiencing. I am really interested in these cobras because I also feel like the vectors are in the grey area where they are going half way down, or even in tight turns catch more water when they are up because the back of the boat goes so far down in the water.

 

[JetBoatPilot]

@kyle just email me a picture of your thrust vectors and I can tell from looking at them whether or not they have the spray guard.

 

[mrtoastyjr]

If Yamaha could have eliminated this in the twin engine boats by simply making the engines turn in different directions why didn't they? Cost I assume but how much more could it cost to accomplish this (the blades on one of the impellers would have to be reversed as well). It's not like Yamaha is worried about pricing themselves out of the jet boat market, it seems like they raise the price a few thousand every year even when there are no major changes yet they are still the least expensive / best selling boats in their class/size. I can't think of one other brand that sells a comaprable 21' to 24' boat for less than Yamaha msrp.

You'd have to completely redesign the engine to make it spin the opposite direction. Basically mirror the entire thing due to which side of the chain will have tension and what not. The cams would have to be different because of the firing order. I would imagine it would be totally cost prohibitive to "fix" something that not many people even notice.

 

[Ronnie]

I didnt realize the "fix" is so complex. I thought it would be something simple like offsetting the engine/crank from the impeller shaft and connecting the two by gears to reverse the direction the shaft and impeller spin.

 

[Cobra Jet Steering LLC]

Or just add my steering and forgetaboutit.

 

[Beachbummer]

Unrelated thought...on the engines used until 2009 one could imagine the prop spin direction could be modified by adding a new gear to the reduction gear box... Make it spin the other way.... Hard to find an impeller for it and I'm sure a lot of fabrication, but at least less difficult than making the engine spin the "wrong" way...