Nitro Z21 low and high speed porpoise

[sblnchrd]

2020 Nitro Z21 300 pro xs v8 12 “ hyd jkp dual console from new this boat has had a low speed bounce and over 70 bob up and down i have tried it all to fix it put lithiums in 13 different props best is 26p bravo 1 xs moved all heavy gear to rear still had it best top end was 75 with 23 fury light load decided to put 2” bobs spacers on to jackplate and was instantly rewarded with no more bounce and a consistent 77.5 top end at 6200 this is the first time boat has really lifted gonna put my 24 fury on and see if i get more out of it i know the 23 fury wont as it was already on the limiter so if u have this problem try this so now i have 14” of setback

[Longtail1]

Had the low speed porpoise on my 21 z21 with 250 pro. 4-31 group batteries. Ended up moving some weight to the bow and now I can cruse 27mph without it porpoising. Still 69.7 wot. 23 fury 3. Wonder what would happen if wedges were installed?

[Brewerbass]

Wedges are different than spacers. Wedges are meant to gain more trim

[Fishysam]

High speed porpoise is from to much trim and to high of engine height.
low speed porpoise is from to much trim and to high of engine height.

my boat at 4" prop to pad can plane at 17 mph with no porpoise. Raise it to 3.5 and it's 22, raise to 3 and it's 28mph. These are all at max down trim. Just bumping it up will porpoise.

At 3" I have high speed porpoise and can't stop it so bumping down the jackplate to 3.3 is the best all around. I'd bet you have to use a touch less trim and lower the jackplate a quarter inch at a time on top end.

but as far as low speed goes, just burry the jackplate down

[BMCD]

Its not too much trim in my case I can guarantee that, Now could be engine height.

wow 28mph at 3 Inches, I am seeing low 20s at that setting to be on plane, But on plane prolly has different meanings to some.

Good to know on the spacers, I am see-ing this when I run over 70 with my setup. I do think I also have some weight distribution issues.

[Longtail1]

Wedges are different than spacers. Wedges are meant to gain more trim

Yes you would be correct. I was wondering if the wedges were inverted (don’t know if it’s even possible) to give you more downward trim, that it that would help with porpoise at slow speeds. Maybe I’m in left field and need reeled back in.