Bleeds-off speed in turns

[GoVols01]

My boat seems to cavitate and bleed-off a lot of speed whenever I turn - no matter how sharp the turn. Does everyone else's boat do this as well?

 

[Jgorm]

Don't all boats do this?

 

[Dave burke]

Mine bleeds off in harder turns but it doesn’t cavitate

 

[W3bexec]

Speed bleed off is normal during turns.

 

[captras]

Because of the increased drag when the boat is in a turn, losing speed is common for all boats (no different than an aircraft in a bank turn). Because of increasing the drag, part of the power is being utilized to turn the boat. Without an increase in power to maintain the turn, something has to be sacrificed. So to maintain speed, you have 2 options. ..stop/reduced the turn amount or increase the power. For other than extreme turns, you should not experience cavitation.

 

[GoVols01]

My I/Os didn't seem to bleed-off as much as my current boat. This is especially noticeable when pulling the kids behind the inner tube.

 

[2kwik4u]

My I/Os didn't seem to bleed-off as much as my current boat. This is especially noticeable when pulling the kids behind the inner tube.

Mine does this BADLY.....It's a considerable drop compared to my old I/O. I've installed the L13 Cone, and resealed the jet pump as an attempt to remedy the problem. It's better, but still not nearly the same as with the I/O. I'm just learning to deal with it mostly.

https://jetboaters.net/threads/multiple-questions-on-2017-ar190.14449/ <--I've chronicled the process here (as well as other random stuff)

 

[NorfolkJames]

I'm more worried about the wife making me bleed when I scare her with a high speed turn.

 

[Jameson Clark]

Like everyone else, mine slows down a TON more than my previous I/O's.

 

[Gym]

The jets do this more than IOs in that the intake tunnel that directs the smooth flow of water to the impeller is at an angle to the nozzle while in a turn which loads the impeller and reduces thrust. An IO's intake is the foward part of the prop which is always in direct alignment with the thrust side of the prop. As others have mentioned you will always get increased drag in a turn, with any technology, due to normal drag considerations on the hull but that is compounded with current jet technology. If our jets were mounted to steerable pods so the intake was always in direct alignment with the thrust this aspect of drag would be eliminated.

 

[swatski]

My boat seems to cavitate and bleed-off a lot of speed whenever I turn - no matter how sharp the turn. Does everyone else's boat do this as well?

"Bleeding"/losing speed in sharp turns is normal of course, cavitation is not. Do you have much cavitation on hard starts? I mean - WOT from a complete stop? Does it matter which way you turn? Is there a difference?

It will be either pump loading, something not right with your intakes or, alternatively, pump sealing and/or impeller/wear ring issues.

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[swatski]

Mine does this BADLY.....It's a considerable drop compared to my old I/O. I've installed the L13 Cone, and resealed the jet pump as an attempt to remedy the problem. It's better, but still not nearly the same as with the I/O. I'm just learning to deal with it mostly.

https://jetboaters.net/threads/multiple-questions-on-2017-ar190.14449/ <--I've chronicled the process here (as well as other random stuff)

I completely hate to say it, but CObra Ultimates or similar - fins that stay int he water in turns - cure those kinds of tracking issues, in a single engine yammies I can not imagine being without that. Your stern slip/slides away instead of digging in and loading the pumps.

Twins are less prone to any of that, but can still be improved. I feel my boat is currently well tuned and there is not a hint of issues, but I remember the times when it was not, and I know exactly what you are describing. I you ever travel through/around St. Louis - lets try to get together, I want you to drive my boat, exchange notes. My boat usually stays in the slip 20min from Lambert/airport, quick in and out.

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[Bruce]

Something I learned from boat soccer is that applying full trim plants the intakes and allows for much more violent cornering. @Betik learned that a little too well!

It also may explain lesser fuel consumption by boats with trim tabs on rough Bimini crossings.

 

[Adrian @ JB Solutions]

My loss of speed was greatly reduced when I added a steering system.... not sure if I lose much, if any, now.

 

[2kwik4u]

I completely hate to say it, but CObra Ultimates or similar - fins that stay int he water in turns - cure those kinds of tracking issues, in a single engine yammies I can not imagine being without that. Your stern slip/slides away instead of digging in and loading the pumps.

Twins are less prone to any of that, but can still be improved. I feel my boat is currently well tuned and there is not a hint of issues, but I remember the times when it was not, and I know exactly what you are describing. I you ever travel through/around St. Louis - lets try to get together, I want you to drive my boat, exchange notes. My boat usually stays in the slip 20min from Lambert/airport, quick in and out.

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I'd definitely take you up on that if I'm ever in the area. I end up down in Cape Girardeau a few times a year (in laws are down that way), and we've made trips north to St. Louis on the weekends a few times. I'm sure I could break free for a few hours for a test ride.

I was hoping to make it to the Shelbyville gathering this year, in an attempt to get a ride/testdrive another boat to see if it's just mine, systemic, or what. Sadly, it's on my oldest boys birthday weekend, and he starts school on the Monday following, so that isn't going to work out.

 

[Cobra Jet Steering LLC]

something swatski noted in his tests of the mega fangs and magnum a k system on his 24 foot boat.