
06-24-2009
|
 |
Senior Member
|
|
Join Date: Nov 2006
Location: Greater Vancouver B.C. Canada
Posts: 431
Rep Power: 6
|
|
|
High Thrust Props
There are advantages to dropping the pitch in favour of more diameter.
In my case it involves much more horsepower but the concept is the same.
I have a MacGregor with the 50Hp outboard on the back and I too was looking for less speed and more thrust. The prop that came with it was a 3 X 10.25 X 13 and that got me into the 5800 rpm range but I am sure there was a lot of slippage because I did not get 13 pitch speed that I should have. Since my desire was less speed and more thrust I bought a Solas Alcup 4 X 11.4 X 10.5 propeller. The extra ear and larger diameter added more water surface contact which translated into more thrust at lower speeds. Of course my top speed dropped but my low to mid range speeds at the same rpms as the three blade actually increased somewhat, not a lot but a bit better. I also gained much more control at low speeds and reverse when docking which was an added bonus.
If you can get a four blade for your engine or even the bigger dog eared prop you will lose some high end speed but make up for it at low end thrust and manueverability. You will move more water and have better control.
Another little change you can look at is cupping. Some props have a little cup ridge on the trailing edge of each blade which helps the prop get a better grip on the water, the Solas Alcup has this feature. At any rate a prop that moves more water at slower speeds will enhance your low end power and manueverability.
|