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Cobra Jet Steering
- Thread starter tomz240
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moosehead
New Member
It feels like the most handling concerns come from those who have spent most of their helm time piloting traditional drives. Once you get the hang of using F-N-R at idle, the jet drives work well, maybe even better, in tight spaces.
Sounds like the CJ adds may help most while docking in rougher water or when relying upon different family/friends to dock the jet crafts, not sure. YMMV.
Sounds like the CJ adds may help most while docking in rougher water or when relying upon different family/friends to dock the jet crafts, not sure. YMMV.
On Yamaha
I had the Cobra Jet fins on my Yamaha jet boat, they were immensely helpful especially in windy conditions or fast moving water. They prevent the spin out of control in high wind dealie. Very good product with no drawbacks except the sharp edges can cut you on boarding if you step on them
I had the Cobra Jet fins on my Yamaha jet boat, they were immensely helpful especially in windy conditions or fast moving water. They prevent the spin out of control in high wind dealie. Very good product with no drawbacks except the sharp edges can cut you on boarding if you step on them
biffdotorg
Active Member
I would be very interested in these for my X20. The guys on the Yamaha JetBoaters site swear by them and can't imagine having the boats without them once installed.
The Mercury 240 in my boat may not benefit like the Yamahas. I do see that the cobra fins for the 240 Merc are "prototype" with a 30 day money back guarantee. Hmm, I may need to "beta" these for $169.
I would love to see what these look like installed on the Merc first. Steering in reverse would be what I am looking for, but I am sure these are not the solution.
Please post photos if anyone jumps on board with the merc prototype as I want to try these too! I may have to email them.
Good luck all!
The Mercury 240 in my boat may not benefit like the Yamahas. I do see that the cobra fins for the 240 Merc are "prototype" with a 30 day money back guarantee. Hmm, I may need to "beta" these for $169.
I would love to see what these look like installed on the Merc first. Steering in reverse would be what I am looking for, but I am sure these are not the solution.
Please post photos if anyone jumps on board with the merc prototype as I want to try these too! I may have to email them.
Good luck all!
biffdotorg
Active Member
I just dropped a line to Jeff at Cobra Jet requesting further info for the Mercury owners on this forum. Hopefully we will see more photos and info on the new prototype direct attach kit they are putting out.
More info to come soon!
More info to come soon!
biffdotorg
Active Member
Just heard back from Jeff at Cobra Jet.
He was telling me the Merc product is not a prototype and has been in production a number of years. (not sure why it says that on the website then)
He sent the directions for install and a picture of the unit. It's still a tough one to imagine on there as the photo is not shown installed. And the directions leave something to be desired. No picts either. (illiterates like us need pictures!!!)
Anyway, the directions look easy and if it performs like the Yamaha guys rave about, it would be worth it. $169 plus shipping is a fair price.
Anyone have a pic of this installed on a merc?
Thanks in advance!
He was telling me the Merc product is not a prototype and has been in production a number of years. (not sure why it says that on the website then)
He sent the directions for install and a picture of the unit. It's still a tough one to imagine on there as the photo is not shown installed. And the directions leave something to be desired. No picts either. (illiterates like us need pictures!!!)
Anyway, the directions look easy and if it performs like the Yamaha guys rave about, it would be worth it. $169 plus shipping is a fair price.
Anyone have a pic of this installed on a merc?
Thanks in advance!
biffdotorg
Active Member
OK, so I ordered a set of the fins, and Jeff shipped them out quite quickly.
Of course I run out real quick to the back of the boat to see what it will look like on the nozzle.
First thing I note is that the fins are parallel and uniform from cobra jet. But he metal piece that goes around the nozzle is probably a quarter inch too narrow and leaving a half inch gap at the bottom when held up to the nozzle.
I'm thinking it is just designed to be clamped down and allows for the unit to be tight once clamped and that is exactly how it worked. The sides spread just enough to get it in place. After adjusting a bit for reverse hood clearance I used a punch to mark the inner 4 holes. There was no way I was going to punch the outer 4 until I had those first 4 in as the spread of the metal would have been way off.
I drilled pilot holes and then the larger holes that were bolt size. I chose to go all the way through and use the included nuts rather than tap the holes for threads. I also chose to purchase lock washers as suggested by others that had done the install.
After doing all 8 holes, the unit seems very solid. I do have two very valid points and tips. 1. Don't over torque the nuts as these are small screws and you will twist them right off. 2. After forcing the unit onto the nozzle, the fins are not perpendicular with the jet and not parallel with each other as they were before installation. This was caused by the "cup" of the mount being smaller than my nozzle. I am guessing a little prying with a 2x4 will even them up. I can only hope this will not damage them. I will do this slowly and hope for the best as I can only assume odd angles can only cause handling problems. I hope to have it in the water this weekend.
Mark
Of course I run out real quick to the back of the boat to see what it will look like on the nozzle.
First thing I note is that the fins are parallel and uniform from cobra jet. But he metal piece that goes around the nozzle is probably a quarter inch too narrow and leaving a half inch gap at the bottom when held up to the nozzle.
I'm thinking it is just designed to be clamped down and allows for the unit to be tight once clamped and that is exactly how it worked. The sides spread just enough to get it in place. After adjusting a bit for reverse hood clearance I used a punch to mark the inner 4 holes. There was no way I was going to punch the outer 4 until I had those first 4 in as the spread of the metal would have been way off.
I drilled pilot holes and then the larger holes that were bolt size. I chose to go all the way through and use the included nuts rather than tap the holes for threads. I also chose to purchase lock washers as suggested by others that had done the install.
After doing all 8 holes, the unit seems very solid. I do have two very valid points and tips. 1. Don't over torque the nuts as these are small screws and you will twist them right off. 2. After forcing the unit onto the nozzle, the fins are not perpendicular with the jet and not parallel with each other as they were before installation. This was caused by the "cup" of the mount being smaller than my nozzle. I am guessing a little prying with a 2x4 will even them up. I can only hope this will not damage them. I will do this slowly and hope for the best as I can only assume odd angles can only cause handling problems. I hope to have it in the water this weekend.
Mark
biffdotorg
Active Member
Sorry for the misunderstanding. On Yamaha boats, the fins are attached to each of the nozzles on a flat surface, you are right.
I am installing on a Challenger X20 with the Mercury M2. This nozzle is round and the CobraFin setup is installed directly to that round surface. The Stainless Cobrajet assemblly is a half moon shape and connects to the bottom half of the nozzle with 8 screws.
Take a look at the two attached photos taken from another person's install.
You will see the way it mounts and also note that once the unit is installed on their jet, the fins actually point outward, rather than perpendicular to the water line on the boat.
I hope that is not an issue as mine is not in the same shape it was out of the box either. I'm guess his mounting point was wider than the nozzle causing the fins to spread. Mine were narrower, causing my fins to get closer together.
I hope that explains the situation better.
I am installing on a Challenger X20 with the Mercury M2. This nozzle is round and the CobraFin setup is installed directly to that round surface. The Stainless Cobrajet assemblly is a half moon shape and connects to the bottom half of the nozzle with 8 screws.
Take a look at the two attached photos taken from another person's install.
You will see the way it mounts and also note that once the unit is installed on their jet, the fins actually point outward, rather than perpendicular to the water line on the boat.
I hope that is not an issue as mine is not in the same shape it was out of the box either. I'm guess his mounting point was wider than the nozzle causing the fins to spread. Mine were narrower, causing my fins to get closer together.
I hope that explains the situation better.
Attachments
biffdotorg
Active Member
yes, we got out last weekend.
I would love to be the guy that was as excited as the yamaha folks, but it just isn't so. That's not to say they didn't help, because they did, just not in the capacity that I had my hopes up for.
Low speed forward, like when approaching a dock or trailer were improved and it was a noticeable difference. I think those of us with the Mercury M2 really want control in reverse. And these didn't seem to change it in the least.
I think Mercury users realy need to get under their boat and look at what the reverse hood does. When the jet nozzle is straight, and the hood is down, it blows water out the sides more than anything, so no fin can help counter that.
When the jet nozzle is at full lock, left or right, that force is shot to that side, and it is opposite what the fins are trying to do. The jet is a stronger force and they actually counter each other. The jet wins.
This is why those that have learned to steer this boat in reverse will have the wheel at full lock left or right. Anything in between is for braking purposes only.
That being said, ability to control the boat at low speed in forward is improved with the Cobra fins, and I still think that is worth the price as it allows you to approach docks and the trailer more accurately and help eliminate the need to use reverse as much.
I am finding out that in reverse that full lock in one direction lets me turn, and full lock in the other seems to allow me to backup straight. It just all seems so counter intuitive. The more one does it, the more it will seem natural.
Jeff builds a good product at Cobra Jet and your mileage may vary with a rotax based, or Four Stroke SeaDoo. Heck, I may still have a better reaction to these once I get the fins parallel with each other. Like I mentioned in a previous post, once installed, the fins were not parallel with each other as the mount was narrower than my nozzle.
A key point to make for anyone considering these: These are not stainless steel blades that you are mounting under your swim deck. You should not have to worry about the kids cutting themselves on them. They are not sharp and it would take a serious blow to hurt anyone with them. If these cut or bruised someone, that person was in the wrong place to begin with.
One catch 22 that is evident as well. They do drop below the line of the hull. Not enough to do as much good as they could if they were 2" lower, but then again not enough as to eliminate the shallow draft of the jet drive. Many people worried about losing all the benefit of not having an outdrive.
So I would bet if someone went to Jeff and said, I am in sandy lakes and shallow draft is not as much concern for me, give me 2" more rudder, he would probably produce a set. I would consider it. Heck, I'm running the same waterways as the guys with Nautiques and Mastercrafts and they have a monster prop and rudder underneith them!
I hope this is helpful and I look forward to more time on the boat and more of your questions. This is by no means a shot at the Cobra Jet fins, I still think it's worth the money. I just won't get to play with these much more as ice and snow will soon be coming to the lakes of Minnesota!
Good luck all!
I would love to be the guy that was as excited as the yamaha folks, but it just isn't so. That's not to say they didn't help, because they did, just not in the capacity that I had my hopes up for.
Low speed forward, like when approaching a dock or trailer were improved and it was a noticeable difference. I think those of us with the Mercury M2 really want control in reverse. And these didn't seem to change it in the least.
I think Mercury users realy need to get under their boat and look at what the reverse hood does. When the jet nozzle is straight, and the hood is down, it blows water out the sides more than anything, so no fin can help counter that.
When the jet nozzle is at full lock, left or right, that force is shot to that side, and it is opposite what the fins are trying to do. The jet is a stronger force and they actually counter each other. The jet wins.
This is why those that have learned to steer this boat in reverse will have the wheel at full lock left or right. Anything in between is for braking purposes only.
That being said, ability to control the boat at low speed in forward is improved with the Cobra fins, and I still think that is worth the price as it allows you to approach docks and the trailer more accurately and help eliminate the need to use reverse as much.
I am finding out that in reverse that full lock in one direction lets me turn, and full lock in the other seems to allow me to backup straight. It just all seems so counter intuitive. The more one does it, the more it will seem natural.
Jeff builds a good product at Cobra Jet and your mileage may vary with a rotax based, or Four Stroke SeaDoo. Heck, I may still have a better reaction to these once I get the fins parallel with each other. Like I mentioned in a previous post, once installed, the fins were not parallel with each other as the mount was narrower than my nozzle.
A key point to make for anyone considering these: These are not stainless steel blades that you are mounting under your swim deck. You should not have to worry about the kids cutting themselves on them. They are not sharp and it would take a serious blow to hurt anyone with them. If these cut or bruised someone, that person was in the wrong place to begin with.
One catch 22 that is evident as well. They do drop below the line of the hull. Not enough to do as much good as they could if they were 2" lower, but then again not enough as to eliminate the shallow draft of the jet drive. Many people worried about losing all the benefit of not having an outdrive.
So I would bet if someone went to Jeff and said, I am in sandy lakes and shallow draft is not as much concern for me, give me 2" more rudder, he would probably produce a set. I would consider it. Heck, I'm running the same waterways as the guys with Nautiques and Mastercrafts and they have a monster prop and rudder underneith them!
I hope this is helpful and I look forward to more time on the boat and more of your questions. This is by no means a shot at the Cobra Jet fins, I still think it's worth the money. I just won't get to play with these much more as ice and snow will soon be coming to the lakes of Minnesota!
Good luck all!
biffdotorg
Active Member
Exactly, the jet is being redirected by the hood and not running the force over the fins.
Take a look at the hood, once dropped it doesn't thrust in the direction you would think it would.
A Yamaha jet nozzle, has the hood attached to the nozzle, so the hood literally reverses the thrust, and when the nozzle turns, the hood moves with it.
A Mercury M2 hood is fixed, other than from the F-N-R positions (up and down). The nozzle moves within the hood, and the thrust is redirected away from the fins. All you can hope for is that this thrust pulls the boat in a direction that the fins can act like a rudder. And in this case, the rudder-effect is not great enough.
I cannot say this for the Rotax and Four-stroke model Seadoo boats and I have not seen how the reverse hood is attached. I would guess it is much more Yamaha-like. No offense guys, it's just for conversation sake.
Take a look at the hood, once dropped it doesn't thrust in the direction you would think it would.
A Yamaha jet nozzle, has the hood attached to the nozzle, so the hood literally reverses the thrust, and when the nozzle turns, the hood moves with it.
A Mercury M2 hood is fixed, other than from the F-N-R positions (up and down). The nozzle moves within the hood, and the thrust is redirected away from the fins. All you can hope for is that this thrust pulls the boat in a direction that the fins can act like a rudder. And in this case, the rudder-effect is not great enough.
I cannot say this for the Rotax and Four-stroke model Seadoo boats and I have not seen how the reverse hood is attached. I would guess it is much more Yamaha-like. No offense guys, it's just for conversation sake.
biffdotorg
Active Member
Sorry to say, it was a family day and the water temps have dropped greatly, so no high speed manuevers were allowed. It was noticable at most forward speeds.
Since handling really wasn't an issue on plane, I had little hopes for much improvement. I run a river with my X20 and handling on plane was important to me. This boat had no real issues with that to begin with.
It will be fun next spring to see if it helps when towing a tube or skier, but I had little issue with that either. This 20ft boat stays planted pretty well.
Since handling really wasn't an issue on plane, I had little hopes for much improvement. I run a river with my X20 and handling on plane was important to me. This boat had no real issues with that to begin with.
It will be fun next spring to see if it helps when towing a tube or skier, but I had little issue with that either. This 20ft boat stays planted pretty well.
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