Video - Test Results - Cobra Jet vs Jet Boat Pilot

[Weeb]

I'm sure the mega fangs will be more than adequate, I'm done spending money on my rear end.

 

[Ronnie]

Im on the fence as to whether to purchase teo pairs of mega fangs or one pair plus lateral thrusters. Most likely it will be the former, it depends on how much money i have left in the maintenance, repair and upgrade budget this year.

 

[Cobra Jet Steering LLC]

Well in your situation I would suggest a single pair of mega fangs to be placed on the outside and leave the regular fangs on the inside first and then see how big a difference you see There are a lot of people who could do that since they have the regular fangs. this would be a very inexpensive upgrade and A financially practical direction to go in first.

 

[Thompsbren]

Nice video. Is it possible the speed difference is the result of a trim difference created by the Cobra Jet? (Bow being pushed down slightly). I know in theory less hull in the water means more speed but one of the disadvantages of these boats in my experience is the inability to change trim when you have different weights or water conditions. The 190 seems setup very bow high and the 210 is likely similar to account for possible passengers up front. Running solo the Cobra Jet fins may bring the boat to a more efficient trim angle. Just a thought.

 

[swatski]

Nice video. Is it possible the speed difference is the result of a trim difference created by the Cobra Jet? (Bow being pushed down slightly). I know in theory less hull in the water means more speed but one of the disadvantages of these boats in my experience is the inability to change trim when you have different weights or water conditions. The 190 seems setup very bow high and the 210 is likely similar to account for possible passengers up front. Running solo the Cobra Jet fins may bring the boat to a more efficient trim angle. Just a thought.

Good point, but I don't think so.
CObra Vipers could do that, conceivably, ( and that could be a part of their charm) but the AKs or Ultimates w/ or w/o Fangs/MEAGs - no way, those just cut through the water.

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[Foobar]

Going back to the JBP system. Works better for me in moving tides. I regularly position the boat using reverse for fishing. Tide was rolling today and I didn't have the thrust to move the boat in reverse against the tide. I previously made the same maneuver with the JBP system and it works better. I can live without the steering improvement the Cobras give when coming off plane. I can use reverse on one side to compensate. However, I can't replicate or compensate the same capabilities the lateral thrusters give me in reverse.

 

[JetBoatPilot]

Over the years our customers have most often requested slow speed steering improvement while moving forward and reverse maneuverability improvement. Both the Thrust Vectors and Lateral Thrusters were purpose built to solve those specific problems. I know the other systems will serve a purpose but from our data the requests for improving high speed steering have been below the threshold necessary for serious consideration. Additionally I don't think anyone has ever asked for more reverse thrust or reverse speed.

I'm pleased you're going to stick with the Lateral Thrusters and I look forward to hearing additional feedback as you are able to share it!

 

[Neutron]

I like the added steering control at speed with the Cobras(no fangs) with the added reverse control with the Lateral Thrusters

To me its the best combo for all around control.

I didnt feel that the steering at speed was any harder to turn without the smaller fangs

 

[Foobar]

I like the added steering control at speed with the Cobras(no fangs) with the added reverse control with the Lateral Thrusters

To me its the best combo for all around control.

I didnt feel that the steering at speed was any harder to turn without the smaller fangs

I plan on giving this a try as well.

 

[swatski]

I will never understand why is Yamaha not using a version of their own pump bucket with their own lateral thrusters in their boats (?).
Like those:

A simple (modified) adaptation of that would work perfectly in twins (a very simple mod).
I can not find the post/poster - someone already posted it somewhere here.
Here is the pic (that I saved):

(SORRY FOR NOT QUOTING THE AUTHOR, I WILL UPDATE WHEN I FIND THE POST!)

Obviously this would need some re-design and probably a bunch of testing to get the dimensions and angles right, but it seems like the best approach to generate lateral thrust by the pumps.

I wish I had the time to work on it... Maybe later this year, IDK. This is not a difficult mod, and the functionality is already proven - in the Yamaha's own design.

(because of the angles involved, in a twin one side would be pushing the stern, the other would be streaming into the stern- and dispersing - in reverse)


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[Foobar]

@JetBoatPilot has already cracked the code on this with the lateral thrusters. Two bolts. Done.

 

[swatski]

@JetBoatPilot has already cracked the code on this with the lateral thrusters. Two bolts. Done.

LOL. Yes, he did.
But lets face it, the LTEs have been around for about 5 min. Promising as they look.
The bucket diverters/thrusters have been around for... ever.

Sounds like the LTE do not obstruct the "strait line" reverse in any significant way, shitty as it is (stock). That's good to know! (I think @Neutron posted that, too)

The other potential issue is catching crap in those, like debris stuck in a funnel.

Keep us posted! Your contributions here are by far the most significant, helping us understand how those things work.

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[1_fast_ar240]

Plus they are a bit pricey. I have stock ski buckets maybe somebody wants to try them, not me on the new boat

 

[Neutron]

I will never understand why is Yamaha not using a version of their own pump bucket with their own lateral thrusters in their boats (?).
Like those:

A simple (modified) adaptation of that would work perfectly in twins (a very simple mod).
I can not find the post/poster - someone already posted it somewhere here.
Here is the pic (that I saved):
View attachment 70298
(SORRY FOR NOT QUOTING THE AUTHOR, I WILL UPDATE WHEN I FIND THE POST!)

Obviously this would need some re-design and probably a bunch of testing to get the dimensions and angles right, but it seems like the best approach to generate lateral thrust by the pumps.

I wish I had the time to work on it... Maybe later this year, IDK. This is not a difficult mod, and the functionality is already proven - in the Yamaha's own design.

(because of the angles involved, in a twin one side would be pushing the stern, the other would be streaming into the stern- and dispersing - in reverse)


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The problem with using a setup similar to that type or the ones on a brp powered boat is you need to turn the wheel opposite direction to make the same move we currently do.
My FZS reverse steering is backwards and uses that exact bucket in the first pic.
While on a ski its easy to figure out, on a boat it gets tricky

 

[Cobra Jet Steering LLC]

We seem to be forgetting that there are two different ways available to deal with reverse steering, the mega fangs use the water that has already been diverted by the reverse bucket to the bottom opening of the steering nozzle, this water usually just spreads out and under the hull producing a reverse thrust with little direction so the steer ability of that water is not very effective.
The mega fangs corral that thrust concentrating it in a certain direction and this makes the boat respond very nicely to steering input.
It has many excellent write-ups from people on this board who do not appear to have any outside influence and it has been complimented by those people time and time again. The benefit to this is it also produces a power steering effect as well as a better stopping ability of the reverse thrust over stock results and better power for backing off boat lifts or trailers, This reverse is a true reverse that steers similarly to a regular boat so no surprises.
Additionally it enhances the steering of the boat at a price way below any other option available. We have also gone out of our way to make this available to people with other systems from other manufacturers and vise versa to prove it's compatibility. Therefore people with particular needs can choose the one that serves them best.
I even make a side force stabilizer to allow people using my ultimate system on the new style nozzles to add the other reverse if they so desire. All the information you need is available if you seek it.

 

[swatski]

The problem with using a setup similar to that type or the ones on a brp powered boat is you need to turn the wheel opposite direction to make the same move we currently do.
My FZS reverse steering is backwards and uses that exact bucket in the first pic.
While on a ski its easy to figure out, on a boat it gets tricky

Well, it would only work in twins but no, the steering is not reversed in this concept (in the prototype bucket mod provided by the anonymous jetboater, lol, cited above).

The major difference is - the Yamaha lateral buckets (as in the picture) generate strait line reverse through lateral thrusters, no opening at the bottom. This is not the case with the Yamaha boat (OEM) buckets - which shoot through the bottom of the steering nozzle to generate reverse thrust (albeit that is very weak reverse, and can benefit greatly w/Cobra fangs/megas).

The other major difference - there is only one opening per bucket, towards the outside.

Let's say this is a port side pump (w/steering nozzle bucket w/ left side opening - to port). When turning the pump to the right, water exiting through the left side opening (in the bucket) thrusts/pushes the stern to the right - generating lateral thrust - aiding the OEM reverse that shoots through the bottom opening in the nozzle.

At this point, the other side (built in reverse orientation), which partially cancels the lateral thrust (to the right in the example above), is still pushing the stern to the right because of the angles involved - strbd side /lateral stream water is diverted as it is hitting the transom/stern, and the resulting vector/direction (combined) of the thrust is still to one side.
(this may actually even generate TDE effect - as in OEM thrust directional enhancement, but that is less critical here)

Unlike BRP pumps, with this modification the reverse is natural, not reversed.
Again, that only works in twins.
(whereas the singles should always run w/ Cobras, e.g. Ultimates, for increased lateral stability at speed and MEGAs for reverse, IMO)

That's all. It's a very simple bucket mod /opening (maybe shaped like a short nozzle). Basically, just what Yamaha already has but enclosed in the outside direction on both pumps.

Maybe I'll draw something later, when I stop running around at work.

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[JetBoatPilot]

@swatski I think the flaw in the image you attached is that the reverse buckets would force water laterally any time they were in the down position. You'd have a cancelling effect if both buckets were down at the same time. The Lateral Thrusters are active only when the reverse discharge is directed over the Lateral Thruster inlet. This means that when one side is pushing water out laterally the other side is not, so you won't have the cancellation in thrust. Additionally there is no need to instruct someone on the operation of the system. There is no way to get it wrong. Very helpful for beginners such as wife, kids and new boat owners. Also Lateral Thrusters work on single engine models as well. This design appears to be for twins only.

I think the system pictured could work for someone very experienced with the system installed but it would take alot of time to get proficient with it. I see a lot of possibilities for counterproductive thrust. Unfortunately during docking maneuvers you must think quickly and execute quickly so a system like this could be stressful to use as well.

 

[swatski]

@swatski I think the flaw in the image you attached is that the reverse buckets would force water laterally any time they were in the down position. You'd have a cancelling effect if both buckets were down at the same time. The Lateral Thrusters are active only when the reverse discharge is directed over the Lateral Thruster inlet. This means that when one side is pushing water out laterally the other side is not, so you won't have the cancellation in thrust. Additionally there is no need to instruct someone on the operation of the system. There is no way to get it wrong. Very helpful for beginners such as wife, kids and new boat owners. Also Lateral Thrusters work on single engine models as well. This design appears to be for twins only.

I think the system pictured could work for someone very experienced with the system installed but it would take alot of time to get proficient with it. I see a lot of possibilities for counterproductive thrust. Unfortunately during docking maneuvers you must think quickly and execute quickly so a system like this could be stressful to use as well.

There are some caveats to the picture above of course - it is a ski bucket (not boat), so that is different, the boat pumps generate reverse through the bottom opening (red arrow):
(shown here by my trusted assistant)



So, yes - there is a flaw with the image I posted (I should have indicated more clearly it was a ski pump, not boat). But there is no flaw with the forces.
It is still all Newton Second Law of Motion. Force, mass and acceleration, and vectors of force/thrust.

Lets compare it to the classic example of two ice skaters pushing on a third.

Illustrating this with the head-to-tail force vectors - where forces are vectors and add like other vectors, so the total force on the third skater is in the direction shown:





So - what would it translate (or look like) - at the stern of a twin engine Yamaha jet boat?

Well, lets see!
(this is not a high quality schematic, lol)


F1 through F5 are water jet vectors, so the thrust (force) would have the reverse vector (direction).
The F5 is water bouncing off of the transom, when the nozzles are turned.
(In addition to F5 there would also be water dispersing up and down, I omitted that here for simplicity, but it could further aid the system the same way the factory TDE works. Not the most important here.)

The bottom line - those deflectors can generate lateral thrust to move the stern to a side.

The above example would work with both buckets down at the same time.
So - this would be a "no skill involved" scenario.

With some skill, one could use only one pump/bucket/lateral thruster, so to push the stern to STRBD one would only use the PORT pump - and the F3-F5 would disappear making the system work more efficient/faster.


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[Lowstar]

There are some caveats to the picture above of course - it is a ski bucket (not boat), so that is different, the boat pumps generate reverse through the bottom opening (red arrow):
(shown here by my trusted assistant)
View attachment 70325


So, yes - there is a flaw with the image I posted (I should have indicated more clearly it was a ski pump, not boat). But there is no flaw with the forces.
It is still all Newton Second Law of Motion. Force, mass and acceleration, and vectors of force/thrust.

Lets compare it to the classic example of two ice skaters pushing on a third.

Illustrating this with the head-to-tail force vectors - where forces are vectors and add like other vectors, so the total force on the third skater is in the direction shown:

View attachment 70323



So - what would it translate (or look like) - at the stern of a twin engine Yamaha jet boat?

Well, lets see!
(this is not a high quality schematic, lol)

View attachment 70322
F1 through F5 are water jet vectors, so the thrust (force) would have the reverse vector (direction).
The F5 is water bouncing off of the transom, when the nozzles are turned.
(In addition to F5 there would also be water dispersing up and down, I omitted that here for simplicity, but it could further aid the system the same way the factory TDE works. Not the most important here.)

The bottom line - those deflectors can generate lateral thrust to move the stern to a side.

The above example would work with both buckets down at the same time.
So - this would be a "no skill involved" scenario.

With some skill, one could use only one pump/bucket/lateral thruster, so to push the stern to STRBD one would only use the PORT pump - and the F3-F5 would disappear making the system work more efficient/faster.


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Holy crap so let me get this straight F5 plus F3 divided by the square root of thrust vector with a skater thrown in........ oh never mind , I agree this should work !

 

[Drift Away]

There are some caveats to the picture above of course - it is a ski bucket (not boat), so that is different, the boat pumps generate reverse through the bottom opening (red arrow):
(shown here by my trusted assistant)
View attachment 70325


So, yes - there is a flaw with the image I posted (I should have indicated more clearly it was a ski pump, not boat). But there is no flaw with the forces.
It is still all Newton Second Law of Motion. Force, mass and acceleration, and vectors of force/thrust.

Lets compare it to the classic example of two ice skaters pushing on a third.

Illustrating this with the head-to-tail force vectors - where forces are vectors and add like other vectors, so the total force on the third skater is in the direction shown:

View attachment 70323



So - what would it translate (or look like) - at the stern of a twin engine Yamaha jet boat?

Well, lets see!
(this is not a high quality schematic, lol)

View attachment 70322
F1 through F5 are water jet vectors, so the thrust (force) would have the reverse vector (direction).
The F5 is water bouncing off of the transom, when the nozzles are turned.
(In addition to F5 there would also be water dispersing up and down, I omitted that here for simplicity, but it could further aid the system the same way the factory TDE works. Not the most important here.)

The bottom line - those deflectors can generate lateral thrust to move the stern to a side.

The above example would work with both buckets down at the same time.
So - this would be a "no skill involved" scenario.

With some skill, one could use only one pump/bucket/lateral thruster, so to push the stern to STRBD one would only use the PORT pump - and the F3-F5 would disappear making the system work more efficient/faster.


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This might be a good time to bring up the fact i am a Army guy whos been in 18 years but joined with a GED lol