21' bleeds-off speed badly in turns

[GoVols01]

Had the kids on an inner tube behind our new 212x Friday for the 1st time. My old I/O didn't loose much speed when turning, but my new boat will go from 27 mph down to 15 while turning and then take several seconds to get back up on plane once I straighten the boat back out. My kids are 10 and 8 and the tube is not one of the gigantic ones either. Is this normal?

 

[haknslash]

Jets are a different breed. You need to power up in the turns or it will slowly bleed off speed. The tighter you turn the more it will bleed off so the more throttle input is required to hold or continue a hard sharp turn. This is amplified by the load on your boat or pulling someone.

I might be mistaken but I think adding Cobra fins helps with this. Someone familiar with them can chime in.

 

[viper15]

X2 .... Pulling tubers is different that pulling a skier or wakeboarder. For pulling skiers and wakeboarders, you essentially drive straight and try to maintain a steady speed. Tubers is altogether different. It's all about turning and speed changes to provide a fun ride for the tubers. So you end up doing a lot of throttle adjustments through harder turns. I think jets scrub off speed a bit more than a prop, so you'll do more power compensation than you are used to.

 

[KXCam22]

With jets i turn less when pulling tubers but use rapid left right steering to use the jet wash to push them around. They like it. Cam.

 

[jdonalds]

This is my biggest (one of a very few) complaints about our 21'.

 

[GoVols01]

How do you guys keep the rope from diving into the jet wash? I've considered buying the "SportsStuff 4K Booster Ball" that mounts midway through the tow rope, but that + the inner tube will take up a ton of room on-board. After seeing the way the rope dives into the wake on these boats, I need to do something. When the rope pops back out of the water, it jerks the tube / kids pretty bad!

 

[nate kennedy]

How do you guys keep the rope from diving into the jet wash? I've considered buying the "SportsStuff 4K Booster Ball" that mounts midway through the tow rope, but that + the inner tube will take up a ton of room on-board. After seeing the way the rope dives into the wake on these boats, I need to do something. When the rope pops back out of the water, it jerks the tube / kids pretty bad!

That is my biggest struggle as well... I thought I read on here that ball didn't do much... if I could get that figured out would make it much more enjoyable for people to tube

 

[GiddYupJoe]

I think I saw a pic of @Julian using the blow up rope ball thingy in a picture recently... maybe he can provide some insight.

 

[Julian]

The ball helps a ton...especially when towing big tubes! When I tow smaller tubes I use the tower, but when the Bandwagon 2+2 comes out so does the booster ball. The ball takes up very little room....not much more than a tow rope does.

These are action shots from Monday:

 

[nate kennedy]

How does it work when pulling a smaller tube? It keeps the rope from getting caught in the wake right? That's my problem when turning even a little it digs into the wake and creates slack and jerks the tube around... does it help at all with the spray?

 

[Julian]

How does it work when pulling a smaller tube? It keeps the rope from getting caught in the wake right? That's my problem when turning even a little it digs into the wake and creates slack and jerks the tube around... does it help at all with the spray?

Works great regardless of the size tube you are pulling. Actually probably works even better with smaller tubes....I just pull the smaller tubes from my tower now....but on my SX230 I'd use it for all the tubes and it helps getting the tube to whip back and forth without dragging through the wake/jetwash.

 

[nate kennedy]

Works great regardless of the size tube you are pulling. Actually probably works even better with smaller tubes....I just pull the smaller tubes from my tower now....but on my SX230 I'd use it for all the tubes and it helps getting the tube to whip back and forth without dragging through the wake/jetwash.

Awesome!! I'm going to order one tonight! Thanks for the feedback!!

 

[eticket]

I've got the ball as well and highly recommend it for better tube towing.

 

[Speedling]

This is what you need to know about the speed "bleed" as you turn, it is from groupk.com which is awesome for the 2 smoke boats and really helped me a ton on my exciter.
About Pump Loading

All technicians that build high performance PWCs quickly learn a few fundamental rules about PWC pump function. As you engage a jet-pump driven watercraft in to a high-speed (power-on) left hand turn, the engine/pump gets very heavily loaded, and engine rpms are usually “pulled down”. However, making a right hand turn at exactly the same speed results in no rpm loss at all … and often results in an rpm increase, often accompanied by mild cavitation.

The reason for this phenomenon is that the entry angle of water coming in towards the impeller has a big effect on how well the pump get “loaded”. In left hand turns, the water comes toward the prop at an angle that very effectively “loads” the pump with water, and allows for very minimal “cavitation”. A hard right hand turn has exactly the opposite effect because the water is coming in toward the prop in a way that is very “unfriendly” to pump loading. Anyone who has driven a single engine Exciter 135 will experience this phenomenon in a big way. Using aftermarket impellers with a better blade/hub design can greatly reduce the cavitation experienced under all conditions …including in right hand turns. But even the best designed prop cannot eliminate right-turn cavitation altogether.

Twin Engine Pump Loading

The phenomenon described above affects the twin motor jet boats in an entirely different way. The water intake surfaces on the bottom of twin motor hulls are on angled surfaces on each side of the hull. This “angled water entry” gives an effective entry angle that mimics the pump loading of turning the boat. This means that (while driving in a straight line) the drivers side pump (starboard) is receiving water at an angle that mimics a left hand turn (thus loading the engine rpms down). At the same time, the passenger side (port) impeller is receiving water at an angle that mimics a right hand turn (resulting in higher rpms and a closer cavitation threshold). This is why the left (port) motors of most twin-engine Yamaha jet-boats tend to run higher rpms than the right (starboard) engines.

Getting past the whole theoretical aspect, the functional result is what’s important.. Because of the phenomenon described above, the right side pump is generating more actual thrust than the left pump at any given rpm. This causes the steering wheel to constantly be “tugging” toward a left hand turn, and at the same time causes the left side engine to rev higher than the right engine in order to generate the same thrust.

After weeks of testing, we eventually resolved all these problems (on twin motor Yamahas) by fitting better design impellers on the pumps, and applying a noticeably steeper pitch to the left hand side prop. The end result is engines that turn virtually identical rpms all the way through the throttle movement range, and an end to the steering wheel constantly “tugging” to the left. In most cases, the “off-the-shelf” pitch of the props we chose were not right on the money, so we custom pitch each pair that we sell to the specs that worked best during our on-water tests. Installing these “staggered pitch” aftermarket impellers is one of the most effective improvements that you can make to your twin motor Yamaha jet-boat.

 

[jdonalds]

Our tow rope does catch in the wake but it doesn't seem to be a problem for me. Perhaps it is due to where I like the tube to be relative to the wake. Since my boat kicks up such a spray in the middle of the wake many kids complain that the spray hurts their face (our favorite tube is a 3 person lay-down tube so their face is the only thing the spray can hit) so I have made it a habit never to allow the tube to ride in the middle of the wake. I like to swing the tube from side to side all the time. Sometimes the tube swings out of the wake completely while sometimes it is on the outer edge of the wake, but never in the middle. So normally the tube is transitioning from side to side, the rope may catch but not for long, and if it snaps as it releases I haven't noticed it. The line is always taught. There is no jerking the tube. By the way I normally tow a tube at about 22 mph, slower for little kids.

 

[GoVols01]

I just ordered a SportsStuff Booster Ball. I'll report back how well it works for us. Thanks for the advice guys!

 

[leizearmx]

@Julian why don't you pull the big tube from the tower? I have only had my boat out a couple times and have yet to pull anything with it as it has been monsoon weather here in upstate NY. I have a 2 person and 3 person lay down tubes.

 

[GoVols01]

This is my first boat that has a tower. Everything I've read states that tubes need to be pulled from the tow point on the stern. Only skiers, wake boarders, and surfers can be pulled from the tower. The boat's manual states that there should be no more that 350LBS pulled by the tower, otherwise you may cause damage to the tower's mounting points. This is likely factory safety overkill, but I'd rather play it safe and just use the boat's tow point for the tubers.

 

[leizearmx]

This is my first boat that has a tower. Everything I've read states that tubes need to be pulled from the tow point on the stern. Only skiers, wake boarders, and surfers can be pulled from the tower. The boat's manual states that there should be no more that 350LBS pulled by the tower, otherwise you may cause damage to the tower's mounting points. This is likely factory safety overkill, but I'd rather play it safe and just use the boat's tow point for the tubers.

OK good enough!! I have seen that warning but didn't know if you had experienced anything while trying to pull it from the tower. Thanks!

 

[Julian]

Many people pull exclusively from their towers with no issue. I pull my smaller tubes from the tower, but the Bandwagon 2+2 is just more pressure than I'd like to put on the tower.