Hull type vs. prop type
09-06-2007, 10:08 AM
#1
Registered
Thread Starter
Hull type vs. prop type
I have a 30' Superboat Y2K, true V, notched transom and 2 small steps.
Being a long single engine boat, it needs bow lift. I have been told by alot of people that I need a round ear prop. I run 2 props, a 30 B1 and a 28 B1. I use the 30 when light and the 28 when heavy. The 30 has been labbed locally with good results, about 2+ mph gain top end. The 28 is stock.
I tried a 29p Hydromotive QIV cleaver style. I did a same day comparison with the 28 B1 and the QIV was 5 mph faster top end. Cruise speeds were the same. The QIV does not handle as well at lower speeds but a totally feel when the RPMs get over 4000. I know I am getting more stern lift and could use a little more bow lift. I have to trim it pretty high. It also takes a while for the speed to catch up to throttle increases.
I was told by a friend that with my bottom design the cleaver style works well and also I should try less diameter and more pitch.
Is this correct info? My X-Dim is 5" below the bottom.
Being a long single engine boat, it needs bow lift. I have been told by alot of people that I need a round ear prop. I run 2 props, a 30 B1 and a 28 B1. I use the 30 when light and the 28 when heavy. The 30 has been labbed locally with good results, about 2+ mph gain top end. The 28 is stock.
I tried a 29p Hydromotive QIV cleaver style. I did a same day comparison with the 28 B1 and the QIV was 5 mph faster top end. Cruise speeds were the same. The QIV does not handle as well at lower speeds but a totally feel when the RPMs get over 4000. I know I am getting more stern lift and could use a little more bow lift. I have to trim it pretty high. It also takes a while for the speed to catch up to throttle increases.
I was told by a friend that with my bottom design the cleaver style works well and also I should try less diameter and more pitch.
Is this correct info? My X-Dim is 5" below the bottom.
09-06-2007, 10:46 AM
#2
Registered
Dependant upon your performance numbers and slip %, you might be able to successfully reduce diameter or simply increase the cup in the tips to assist carry the bow a little higher with the Hydro QIV.
Julie
Julie
