4 blades elminates porpoising on Nitro Z boats

[texasfisher]

For those who have Nitro Z20 or Z21 with porpoising problems try a 4 blade prop. I replaced the stock 3 blade Fury 24p with a Bravo XS 1 26p on mine and it eliminated the porpoising. Also improved the hole shot, ride and steering a lot. I'm sure other 4 blade props, like the Fury4, will do the same thing.

[BigBadBass]

Nice to know! Can you comment on your top end rpm and speed in comparison to your 24 p fury 3 blade? I like my 24p fury but it does porpoise... if you got some numbers to show diff I will appreciate it as I been contemplating switching to 4 blade.. thanks!

[texasfisher]

With the 26p Bravo I got 76 mph at about 6100 rpm. With the 24 Fury I got 75 at about 5900 rpm. But the 24 Fury can probably go faster because when I was running it the pedal stop screw was to far out and I could not get my rpms above 5900.

[BigBadBass]

Wow great numbers for bravo 4 blade. The control out weighs slight decrease speed I bet?

[BMCD]

I did not know there was a problem with Z21s?

[Sun Fish]

I did not know there was a problem with Z21s?

Trim down for what!

[Jig_Man]

I talked with a Nitro R&D guy Friday on the lake where he was working on propping out a boat. I run a Z20 with a 250 Verado, 4 batteries and power poles. He said the Z20 with Verados tend to porpoise with Verados. His suggestion was a 1/2" reverse wedge instead of a prop change.


One of my fishing partners has a 4 blade 24 pitch prop. Do you think it might help?

[texasfisher]

I talked with a Nitro R&D guy Friday on the lake where he was working on propping out a boat. I run a Z20 with a 250 Verado, 4 batteries and power poles. He said the Z20 with Verados tend to porpoise with Verados. His suggestion was a 1/2" reverse wedge instead of a prop change.


One of my fishing partners has a 4 blade 24 pitch prop. Do you think it might help?

I am far from a prop expert, but I had a Z8 (may be similar to Z20) that would get squirrely at around 69-70 with the 3 blade Tempest 25p that came with it. The Z8 never really porpoised, but it chine walked a lot at higher speeds. Also it was hard to steer and turn. It would wear you out trying to drive it fast. I put a 4 blade 26p Bravo XS 1 on it and adjusted the pad to prop distance to about 2 3/4 inches and it changed the hole character of the Z8. Better hole shot, really easy steering, turned like it was on a rail, and just an overall more stable ride at any speed. It would not even start to chine until after 72 or so. My Z21 ran great from the moment I bought it, but I did experience the porpoise effect that the Z8 did not have. Its not bad but its just an odd feeling. People say to trim down, and that does work but your wasting a lot of gas pushing water when your trimmed down. When I replaced the Fury 24 with the 26p Bravo it calmed the Z21 down and made it a lot more fun and easy to drive. You may loose 1 or 2 mph but the ease of driving far outweighs having to wrestle it around. If you partner's 4 blade 24p is a Fury give it a try. Nitro suggests using either a 24 Fury or a 24 Fury4. I would not mess with wedges, just props and jack plate settings. Fury's are propped high and Bravos are propped low. So go up 2 pitches if you go from a Fury to a Bravo.