DOUBLE RUDDER SETUP

[kacz7895]

The width of the blade do not affect the drag as mutch as length of the rudder.As you can see on the photos of my boats i take the wather from the rooster tail behind the prop.

I can messure the length under the hull for you John also the width between the rudders will affect how mutch more rudder you will get in the turn.

I`m away from home at the moment (down under) but i wll PM you John about it.

Anders

anders,

I am building an ezvee from zipkits what lenght do you recomend for a double rudder setup

 

[Anders_Martinelle]

I don`t know what type of boat that is???

You have to test and see

Anders

 

[John Finch]

I don`t know what type of boat that is???You have to test and see

Anders

The Zip kit is basically a 23 degree deep vee, so the setup would probably be the same. it is a wood kit that is very well manufactured with great instructions. I got one and made my own modifications, as I always do. No reflection on the kit design. It is gas powered. I have the twin rudder setup on mine.

 

[John Finch]

I tested this past weekend. The rudders were ahead of the prop and the prop cavitated terribly. When I put it into a left turn the boat cavitated so bad that the boat stopped moving forward. I had to move the rudders further apart to stop the problem. I think the prop is too far back on the boat not allowing to compensate for torque roll even though it is to the right of ceneterline, being 6 inches back reduces lift on the right side of the hull. The rudders ahead of the prop is not working well, so The hardware is off the boat and the prop will be made closer to the transom for the next test. when I made a makeshift bracket to put the rudders further apart the boat did turn left very well.

 

[kacz7895]

jon

WHich twin rudder setup did you use. and are you going to use the twin rudders on the new setup or are you just going use one and move the prop up some

 

[Anders_Martinelle]

John, can you post a picture of it?

Sounds odd that you have so mutch drag.

On My duser 90/100 you can see that i have the rudders next to the prop.

As i said, when i come home i can messure some for you.

I`m in Australia now on my way home .

Anders

 

[John Finch]

John, can you post a picture of it?Sounds odd that you have so mutch drag.

On My duser 90/100 you can see that i have the rudders next to the prop.

As i said, when i come home i can messure some for you.

I`m in Australia now on my way home .

Anders

As it turns out, I had engine problems and did not know until I got home. That is why I was losing speed as the day progressed. I moved the prop to a location between the rudders and the cavitation is a lot less on launch and there is none during a left turn. The boat was tested again with the prop closer to the transom and the boat worked great in both right and left turns. Success! It should be a great offshore boat, but only racing will tell. First race is not until Spring, so the true test will have to wait. No speed was lost using two rudders. 57mph on the radar gun.

 

[Anders_Martinelle]

John, i have messured it now and my rudder blad lengths are 40mm under the V-shape.

They are 140mm apart and if you put a scale under the bottom resting on the rudder you will have close to 65 mm in the water.

That is on a duser 90/100

What did you test??

Anders

 

[John Finch]

John, i have messured it now and my rudder blad lengths are 40mm under the V-shape.They are 140mm apart and if you put a scale under the bottom resting on the rudder you will have close to 65 mm in the water.

That is on a duser 90/100

What did you test??

Anders

Measurements are very close to yours. Thanks for your help.

John