Chine walk issue

[1duganwilliams]

Revolt 30 high speed chine walk issue

 

[Tunedfrog]

You have to give us more than that my friend and welcome in.

 

[tntpoof]

id venture his boat is skipping side to side. without transom planes no help unless its prop wabble.

 

[Greywolf74]

What is a chine in terms of boats? I'm only familiar with that word in terms of animal spines.

 

[WickedFog]

What is a chine in terms of boats? I'm only familiar with that word in terms of animal spines.

 

[Greywolf74]

Gotchya

 

[WickedFog]

Gotchya

Hey, I had to google it. I thought maybe the op was meanin' China Walk

⁹

 

[Tunedfrog]

I'm sure glad I wasn't the only one confused here.

 

[WickedFog]

Now that we got that much all figured out, I am going to have to say @tntpoof beat us to the answer.

 

[Tunedfrog]

I agree, I knew he nailed it just as quick as he raised his hand like Arnold Horseshack.

 

[burnskevin58]

What is a chine in terms of boats? I'm only familiar with that word in terms of animal spines.

The chine is the center of the bottom of the hull. Chine walking is when the boat rocks side to side on the chine, much like a teetertotter.

Revolt 30 high speed chine walk issue

A 3-blade prop will help immensely with chine walking.
Chine walking is usually from the 2-blade prop.
During the rotation of a 2-blade prop both blades are level to the water every half revolution, then when one blade bites the hull is forced over to the right in the opposed direction from torque of that blade, when that same blade exits the water, the torque lessens and the hull rights itself back to the left and due to the engine running the hull keels over more than center (This is why it looks like its walking right and left), to the other direction, over and over again on both sides.
The 3-blade prop has 1 and about 1/2 blade in the water at all times so there is always a blade in the water when the next blade bites, the 3rd blade that is always in the water controls this greatly.
Picking a 3-blade prop.
Being there is 3 blades vs a 2-blade, the diameter of the 3-blade is usually less so the prop will look smaller in diameter and less aggressive pitch. But in the end have the same mechanical force/torque of a 2-blade.

if you want to keep the 2-blade prop, if you notice when you slow down the chine walking goes away, right.
De-tonging the 2-blade prop will help as it will lessen the thrust of the prop without sacrificing speed, but you would want to go with a slightly larger diameter prop to keep from popping the speed control.
I had a prather 31 inch off shore deep vee .21 that I set up surface drive. It chined walked like crazy. I put a 3-blade prop and problem solved.

Another thing that works is to move the whole strut over a mm or two to the right side of transom, this puts more weight of the hull to the left and makes it harder for the torque to list the boat to the right (Torque roll side).
Your boat is what's called a Monoplane, meaning it has a very shallow V hull. It is not on common in racing to see these boats running on one half of the hulls bottom (The right side) as opposed to running on plane on the chime. They do this to stop chine walking (Youngblood Mono's were notorious for this), they do it by using smaller props with more pitch and offsetting the prop to the right. But that's a whole different story.

 

[burnskevin58]

Revolt 30 high speed chine walk issue

One other trick you can do to cure chine walking.
if your running a metal, alloy, or copper prop you can de-cup it at the leading ends.
You will have to make a simple tool from a pair of needle nose pliers. (See Pic)
What you want to do is de-cup the cupped section of prop, not the whole length, but just the tips.
The tips are what cup the water and create the chine walking, so by de-cupping the tips without de-tonging the whole cup is another way to solve chine walking or at least limit it.

Pics of the tool, pic of prop with boxes drawn to show the area.
All you really need to do is flatten them out some. How this trick works.
Being only the tips are flattened out, when the boat is not on plane the prop sits lower in the water, so you still have lots of cup to get the boat on plane. Once the boat is on plane the prop is more or less, higher out of the water, flattening the tips out will allow the transom to slightly sit wetter providing more hull to water contact the water will have enough density to control the chine walking, and also allow the motor/engine to reach slightly rpm due to prop slippage, so you won't see a loss of top speed and most of the time you gain top end. It in layman's terms allows the prop to slip while on plane thus no torque roll without losing speed.
We also have another tool, "A Ball Arbor" that is a steel ball welded to a leg that we use to shape props with, but this simple plier tool will work to.

Unlike most I don't plagiarize other people work, passing it off as my own. I am telling you how it really is or works, in my words.

You don't want them flat as paper but just removing some of the cup. Alloy props are the easiest to work with. But copper props work too with this trick.