Cobra Magnum or Ultimate Fins & JBP Lateral Thruster combo on twin engine

[webberkyle]

First post here after reading a significant volume of great posts about Yamaha Boats and various mods to improve them, specifically an 2016 AR240. I have a floating dock at my house that runs perpendicular on the Hudson river that has a few other boats docking at it. At times we experience significant wind changes and current that can make docking challenging, especially in tight quarters. We use the boat like many with my wife and kids for hanging out on the river and water sports, so a quality wake is important to us.

After reading a ton of posts on steering upgrades I'm pretty dead set on going with the following steering upgrade set up which seems to give you everything.

• Cobra Ultimate AK or Magnum AK Steering System (need help deciding)
• JetBoat Pilot Lateral Thrusters

With this said I'm well aware that this would void the JetBoat Pilot lateral thruster warranty, that your reverse thrust is diminished when turning and that the Lateral Thrusters are not compatible with the Cobra Steering Mega Fangs, so I'd use the regular AK Fangs to provide enough clearance. I also don't want to get into a debate on this thread of which vendor's product is better, has better customer service etc.

Cobra Steering Questions:

1. Does the Cobra Steering System add a lot stress to the pumps and mounting points when turning at sharp radius at high speed?
2. How violent is Magnum AK when doing a hard turn? I'm looking for decent steering in turns when when getting off the throttle, but I'm not looking to launch the wife and kids out of the boat. Is this why the Ultimate AK was released as an alternative to the Magnum AK?
3. What setting is the most popular with the Ultimate AK to find a happy medium of fin in/out of the water when planed?
4. Generally speaking what is more popular the Ultimate AK or Magnum AK system?
5. Why isn't the "Deluxe upgrade" which adds inside top fins available on the Ultimate AK system?

Compatibility Questions:

1. Is the "Deluxe upgrade" for the Magnum compatible with when adding the JBP Lateral Thrusters? Or is it worth that upgrade?
2. Is the Ultimate AK system compatible with the JBP Lateral Thruster or is only the Magnum AK compatible?
3. Are the Super Magnum AK fins compatible with JBP Lateral Thrusters?
4. What size bolt do you need to mount both the Lateral Thruster and Cobra Magnum or Ultimate?

@Cobra Jet Steering LLC
@swatski
@MidnightRider
@JetBoatPilot

 

[Cobra Jet Steering LLC]

Cobra Steering Questions:

1. Does the Cobra Steering System add a lot stress to the pumps and mounting points when turning at sharp radius at high speed? No and we do not need to use any hardened or steel bolts for the fins we use regular stainless 8mm bolts.
2. 
   
3. How violent is Magnum AK when doing a hard turn? Well if you do a wide open turn as hard as you can at full throttle you will probably be sitting on the floor but who does that ? when you turn, it turns and when you decelerate it still turns how you do it is all up to you.
4. I'm looking for decent steering in turns when getting off the throttle, when getting off the throttle it still turns that's it,
5. but I'm not looking to launch the wife and kids out of the boat. Is this why the Ultimate AK was released as an alternative to the Magnum AK? No, Ultimate means it is spring loaded and Magnum means it is not ,both are adjustable but the ultimate systems regardless of the model are selectable, adjustable and spring loaded basically they are the fancy model it's as simple as that.
6. What setting is the most popular with the Ultimate AK to find a happy medium of fin in/out of the water when planed? FULLY DEPLOYED
7. Generally speaking what is more popular the Ultimate AK or Magnum AK system? Magnum AK deluxe and A K -19 deluxe are the most popular, remember the AK-19 means it is for the 2019 or newer nozzles AK means it is for the original articulating keel models prior to 2019 and no AK means they are for the earlier systems prior to any articulating keels.
8. Why isn't the "Deluxe upgrade" which adds inside top fins available on the Ultimate AK system
9. Spring loaded feature limits the inner fin size and location.
10. However I do have deluxe versions of the Ultimate AK and AK-19 with not only the larger inner fins but planing surfaces also included. You just need to ask me directly because the site is being rebuilt and the existing site is being shut off very soon. Just remember on the articulating keel boats the factory rudder takes the hit not the Cobra fins because I keep them above the rudder, I also have the second tie rod added for balance and redundancy. You can adjust your system to provide excellent high speed assistance if you wish or not and anyplace in between, magnum versions or ultimate versions.
11. on a 2016 24 foot boat you should probably add the super magnum ak deluxe system then you can add lateral thrusters or mega fang plus . mega fang plus is only 210 for both nozzles and both the lateral thrusters or the mega fang plus use the bottom nozzle bolt for mounting.

 

[MidnightRider]

Looks like you got most your answers from Cobra Jet. I'll just add from the peanut gallery I did the AKs with LTs in 2018 and have never regretted this setup. Absolutely love it. I'm a big fan of the LTs and I love the "always down" aspect of the Cobra fins. I couldn't be happier with the way this setup performs. Maybe you've already seen it but here was my write up on the install.
https://jetboaters.net/threads/cobra-vm-ak-lateral-thrusters-ready-to-go.17781/
At the time I still had questions as to how I'd like it - after that summer I had no questions anymore.

 

[Jim Davis]

I'm running the AK-19s fully deployed. I found the 2019 242xe was very lacking in the 10 to 20 mph range when it came to turns, at least compared to my earlier 2011 model. Huge improvement now and very smooth turns with little effort. Seems to track better in rough water too. It will give a little more control when power off movement or no wake speed but it seems to me these boats really like to have some thrust for control. Install is pretty easy and comes with all parts needed.

 

[webberkyle]

Thanks, this is great input. Does anyone know the rationale as to why JetBoatPilot takes the stance that fins out of water at speed are better? I can’t find any reasoning.

 

[tdonoughue]

Rationale I have heard is so that at speed you have the original boat feel and steering. The intent was to have the steering assistance at low speed, where it is lacking, rather than at full speed where you have the thrust to steer.

Now, many will argue the merits of that rationale... But that is the rationale I have heard.

 

[Cobra Jet Steering LLC]

Or perhaps one word will sum it up " PATENTS" think about it.

 

[Cobra Jet Steering LLC]

By the way ALL the Ultimate systems have several settings including the UP AT SPEED MODE so you get to try it if you want but you get to decide how they work and how much influence they provide at speed, even the magnum sets all allow you to set the fins in different levels of influence at speed as well so the higher you set them the less high speed influence you get however most people choose the full time settings. Come to think about it Yamaha doesn't even have that option, basically you get what you get. And here is a picture I believe was posted by one of our members a while back ,very enlightening as it shows just how much of the nozzles and rudder are actually in the water at planing speed. And this is the key to my top fins and super fins extra surface area when off plane and automatically reduced at planing speed. I really like that picture it
gave me a lot of ideas
.

 

[Liveto99]

I went with the cobras and love them I had a set of lateral thrusters and sold them. A few people have.

 

[PeterB]

I run the AK’s and LT’s on a 2016 242 and today at a busy fuel dock the attendant said he never saw a jet boat handle so well pulling up for fuel. I think the set up works well but I have not used other systems to compare - I just know it’s much better than stock . I do like to “play” with hard turns - my wife says I think it’s a pwc - but have not pitched anyone out of the boat - yet!

 

[AZMark]

First post here after reading a significant volume of great posts about Yamaha Boats and various mods to improve them, specifically an 2016 AR240. I have a floating dock at my house that runs perpendicular on the Hudson river that has a few other boats docking at it. At times we experience significant wind changes and current that can make docking challenging, especially in tight quarters. We use the boat like many with my wife and kids for hanging out on the river and water sports, so a quality wake is important to us.

After reading a ton of posts on steering upgrades I'm pretty dead set on going with the following steering upgrade set up which seems to give you everything.

• Cobra Ultimate AK or Magnum AK Steering System (need help deciding)
• JetBoat Pilot Lateral Thrusters

With this said I'm well aware that this would void the JetBoat Pilot lateral thruster warranty, that your reverse thrust is diminished when turning and that the Lateral Thrusters are not compatible with the Cobra Steering Mega Fangs, so I'd use the regular AK Fangs to provide enough clearance. I also don't want to get into a debate on this thread of which vendor's product is better, has better customer service etc.

Cobra Steering Questions:

1. Does the Cobra Steering System add a lot stress to the pumps and mounting points when turning at sharp radius at high speed?
2. How violent is Magnum AK when doing a hard turn? I'm looking for decent steering in turns when when getting off the throttle, but I'm not looking to launch the wife and kids out of the boat. Is this why the Ultimate AK was released as an alternative to the Magnum AK?
3. What setting is the most popular with the Ultimate AK to find a happy medium of fin in/out of the water when planed?
4. Generally speaking what is more popular the Ultimate AK or Magnum AK system?
5. Why isn't the "Deluxe upgrade" which adds inside top fins available on the Ultimate AK system?

Compatibility Questions:

1. Is the "Deluxe upgrade" for the Magnum compatible with when adding the JBP Lateral Thrusters? Or is it worth that upgrade?
2. Is the Ultimate AK system compatible with the JBP Lateral Thruster or is only the Magnum AK compatible?
3. Are the Super Magnum AK fins compatible with JBP Lateral Thrusters?
4. What size bolt do you need to mount both the Lateral Thruster and Cobra Magnum or Ultimate?

@Cobra Jet Steering LLC
@swatski
@MidnightRider
@JetBoatPilot

What do you mean by reverse thrust being diminished? I have the lateral thrusters and they are great. I’m thinking I will add basic cobra jet fins to tighten up the steering and minimize all the wander on plane. Is adding the fins going to reduce my maneuverability in reverse?

 

[captainhook]

What do you mean by reverse thrust being diminished? I have the lateral thrusters and they are great. I’m thinking I will add basic cobra jet fins to tighten up the steering and minimize all the wander on plane. Is adding the fins going to reduce my maneuverability in reverse?

Some of the reverse thrust is captured by the Lateral Thrusters to send perpendicularly so some is diminished. It wasn’t really noticeable for me.

Fins shouldn’t have any effect on reverse thrust (except maybe the Cobras that are designed for it which I know little about).