I don't seem to be getting much response over in the general forum, so I will also ask here.

I just upped the horsepower again on my 09 Nordic heat, and was wondering what the fast guys are running for prop-shaft depth (inches below the keel) on a single engined v-hull.

Mine is set at 3.5" below the keel, and at this depth, a 5 bladed prop is pretty manditory in order to get slip below 20%.
Slip at this depth is aproximately 13% with a 30 pitch p5x

4 blade props seem to work best at 4"-4.5" below the keel.
Slip at the 4.5" depth is aproximately 12% with a 30 pitch Bravo prop

My Heat is 28 ft long, has a single step, a small pad, and a notched transom.

What is your prop-shaft depth below the keel?

Chris

I'd have to spend a bit more time to be absolutely certain, but mine is looking just a hair lower.

Boat is 28.8 ft long and in my config (loaded with goodies and stuff) weighs about 5300 lb dry

- just under 4-3/4 inches closer to 4.60 and I run 4 blade.
- Last slip calculation on a 4 blade 28 was 16%



Uncle Dave

I subscribed to this thread because I'm very interested to hear how everyone else's boat is set up. Mine currently has a standard length lower and the prop shaft is about 6" below the keel (probably a little more). The prop slip is 18-22% playing with the numbers with a 30 Lab bravo. I tried a P-5X once, but it lifted the back end and was was too loose. From what I hear, the 5-blade props like to run closer to the surface?
-Tom

I'm running 7.5" prop centerline BUT my boat has a flat pad and if you make a imaginary true "v" it's more like 6 inches. I tried a stellings box and boat wouldn't carry the bow/lost speed,tried a 2" shorty,was dangerous (bow steered) and went slower,added a 1" spacer with 2" shorty,still sucked. My problem I think is boat climbs out of water so far at 90-95 mph it acts like it is much higher and everything I did to raise it just killed the boat. I tried a 5 blade prop a few years ago and almost instantly broke a prop shaft (1000 ft lbs of tq),I'd like to see everyones answers,Smitty

I already have a thread here with a lot of feedback with almost the same description. I can pull it to the top.
After pulling it ttt, I see you were one of the first to post input. Good luck finding the perfect setup. Raising mine sure made a big difference, at 5" I can still use a Mirage with 9.8% slip.