• Welcome to Jetboaters.net!

    We are delighted you have found your way to the best Jet Boaters Forum on the internet! Please consider Signing Up so that you can enjoy all the features and offers on the forum. We have members with boats from all the major manufacturers including Yamaha, Seadoo, Scarab and Chaparral. We don't email you SPAM, and the site is totally non-commercial. So what's to lose? IT IS FREE!

    Membership allows you to ask questions (no matter how mundane), meet up with other jet boaters, see full images (not just thumbnails), browse the member map and qualifies you for members only discounts offered by vendors who run specials for our members only! (It also gets rid of this banner!)

    free hit counter

2019 reverse bucket impact of fins or tvs

mwalker4

Jetboaters Lieutenant
Messages
488
Reaction score
547
Points
167
Location
Delaware County, Ohio
Boat Make
Yamaha
Year
2019
Boat Model
SX
Boat Length
19
I have 2019 sx190 which has the new reverse bucket. It provides thrust at an angle to improve steering. I ran my boat a few times without fins. Then added Cobrajet super ultimates. They had the desired effect going forward but I THINK they muddied up the reverse by blocking the sideways thrust of the new bucket. It is hard to tell for sure so I thought I would ask if anyone else has a similar experience. I think it might be the same for TVs.

Luckily, the fins are adjustable and I can raise them up which will get them out of the way. Of course this will reduce their effectiveness on plane but that is not my main concern. I don't think it will have a huge impact at low speed. Does anyone have experience raising the fins?
 

mdurz420

Member
Messages
2
Reaction score
1
Points
20
Boat Make
Yamaha
Year
2019
Boat Model
AR
Boat Length
19
I just got a 2019 AR190 and I’m wondering the same thing. Based on appearance alone they sure look like they’d make reverse not as effective
 

Cobra Jet Steering LLC

Jetboaters Admiral
Vendor
Messages
5,865
Reaction score
5,351
Points
452
Location
Florida
Boat Make
Yamaha
Year
2021
Boat Model
Other
Boat Length
Other
Did you set them at the #4 and #5 position like the instructions recommended? That is where the 19 foot setting should start but you can change it to what ever you feel good with this is the reason the adjustments are there, you can change the position but I never suggest you go lower than the 4 and 5 setting on a 19 foot boat
 

Attachments

swatski

Jetboaters Fleet Admiral 1*
Messages
12,806
Reaction score
18,566
Points
822
Location
North Caldwell, NJ
Boat Make
Yamaha
Year
2016
Boat Model
AR
Boat Length
24
Luckily, the fins are adjustable and I can raise them up which will get them out of the way. Of course this will reduce their effectiveness on plane but that is not my main concern. I don't think it will have a huge impact at low speed. Does anyone have experience raising the fins?
Looks like it's similar in twins, @BakedZiti picture shows it nicely - there is some overlap depending on how the fins are set. Good to know:
I would be interested to know the answer to this although I would be shocked if @Cobra Jet Steering LLC would design something that would cause this problem, this is a picture of my setup, doesn't look like the fins are in the way, btw i have since added the fangsView attachment 98464
 

mwalker4

Jetboaters Lieutenant
Messages
488
Reaction score
547
Points
167
Location
Delaware County, Ohio
Boat Make
Yamaha
Year
2019
Boat Model
SX
Boat Length
19
Did you set them at the #4 and #5 position like the instructions recommended? That is where the 19 foot setting should start but you can change it to what ever you feel good with this is the reason the adjustments are there, you can change the position but I never suggest you go lower than the 4 and 5 setting on a 19 foot boat
I had it set in 4 and 5. I am planning to try 1 and 2.
 

swatski

Jetboaters Fleet Admiral 1*
Messages
12,806
Reaction score
18,566
Points
822
Location
North Caldwell, NJ
Boat Make
Yamaha
Year
2016
Boat Model
AR
Boat Length
24
I had it set in 4 and 5. I am planning to try 1 and 2.
It will be interesting to see if that (negatively) effects your strait reverse thrust.
The slight (and variable) overlap in the new (2019) reverse nozzle with the fins must have been intentional, knowing Cobra.

--
 

mwalker4

Jetboaters Lieutenant
Messages
488
Reaction score
547
Points
167
Location
Delaware County, Ohio
Boat Make
Yamaha
Year
2019
Boat Model
SX
Boat Length
19
@Cobra Jet Steering LLC, I believe you haven't been able to get a 2019 bucket yet. When you do get one and possible test with one, I would love to have your thoughts on the need for a reshaped fin and the impact of it. The picture below is a fin in the 4 and 5 position. I think you can see why I am concerned with the port output appearing to be directed into the fin. I believe moving to 1 and 2 with the current fin will restore my reverse steering, lessen the improvement of the fins on plane, and not sure of the impact on forward slow speed steering. With a reshaped fin, I could keep the on plane impact and minimize any forward slow speed steering impact. I will be changing the position a few times in the next couple of weeks to see if there is definitely an issue.
98516
 

mwalker4

Jetboaters Lieutenant
Messages
488
Reaction score
547
Points
167
Location
Delaware County, Ohio
Boat Make
Yamaha
Year
2019
Boat Model
SX
Boat Length
19
It will be interesting to see if that (negatively) effects your strait reverse thrust.
The slight (and variable) overlap in the new (2019) reverse nozzle with the fins must have been intentional, knowing Cobra.

--
I hope so, but from discussions with Cobra the only change made from the 18 to the 19 is wider spacers for the wider pump assembly.
 

Cobra Jet Steering LLC

Jetboaters Admiral
Vendor
Messages
5,865
Reaction score
5,351
Points
452
Location
Florida
Boat Make
Yamaha
Year
2021
Boat Model
Other
Boat Length
Other
I just want to mention again one thing you want to be aware of is NEVER try to power up any jet boat in any shallow water as you will kick up all sorts of bottom debris and put it in your pump intake Yes there is a reason I do the fins the way I do and had that been an issue it would have been pointed out last year when I started making the AK-19 steering systems, I sure heard about the couple of springs that caught on the reverse hood.
 

mwalker4

Jetboaters Lieutenant
Messages
488
Reaction score
547
Points
167
Location
Delaware County, Ohio
Boat Make
Yamaha
Year
2019
Boat Model
SX
Boat Length
19
Since Cobra Jet has redesigned its fins and I just saw Jet Boat Pilot has a new lateral thruster 2.0 and redesigned fin, I guess the answer was Yes, the original fins did block the lateral flow. Now I wonder at what setting the redesigned Cobra Jet fin is compatible with the new lateral thruster 2.0 or would I need to switch to Thrust Vectors to use the new lateral thruster 2.0?
 
Top