View Full Version : Help me

01-31-2011, 04:50 AM
this is my small 18'' boat i made it has standard 540 with a rudder of to the side below the hull look at picture but i need a surface drive propeller as soon as it gets on the plane it sucks air and makes alot of noise and goes a little faster than walking speed HELP:help:

01-31-2011, 09:08 PM
The boat you've built is setup for subsurface props.
It screams and pumps air at high revbecause the prop is out behind the back, and can channel air in from the surface.. put the prop under the hull and it wont cavitate ( screamand pump air ! )
A surfacing prop is setup diff to what's here.. the strut come sout the backl of the boat, and when planing only 1/2 the prop can 'see' the water.
Sure, surface props can run faster, but the boat you have looks more a displacement type, which wouldnt go so well as a surface drive.


02-01-2011, 04:05 AM

Thankyou so much what if i move the prop back 2 cm its moved forward in this picture because i was seeing the difference when i move the prop but if i move it back as much as possible can you reconmend a prop to use

02-01-2011, 04:40 AM
It's not the fwd/bkwd thats sub/surfacing..
you need to raise the whole shaft to make the prop a surfacing one.
Take a look at most the monos here and the shaft comes out the back ( transom) of the boat... so that the hub of the prop doesnt touch the water when the boat is at speed.
Not knowing whats inside yours for power/batteries..I dont thing a surfacing prop would be ideal here.
0414 794 022