ZX200, new Atlas hydraulic, now porpoising; CB Foil fixed it!
ZX200 with new Atlas hydraulic from Slidemaster manual, now porpoising (sorry to bring this up again and perhaps beat a dead horse):
I've got a 2009 ZX200 hull I just re-powered with a new 2018 SHO200 (replacing an identical 2011 SHO200) and reusing the original stock prop. While doing that I "upgraded" a few items. I pulled off the old Power Pole Pro and original sandwiched PP mounting plate. I installed a 10" Atlas hydraulic plate (in place of the original 10" Slidemaster which had no wedges and was set with a full 5 dots showing). Also installed new side mount PP plates and a pair of PP 8' Blades. So a bit of added weight to the rear with the second pole/pump, and Atlas plate with its cylinder/motor. Also pretty full on fuel currently in both tanks. The motor is bolted to the plate with one available Yamaha hole above and two available below (so the motor could be raised two holes higher or lowered one hole down), which I believe is typical?
The boat now porpoises pretty bad in the 20-30 mph range. It didn't do that before at all at any speed while tilted fully down. No matter what speed, when tilted down all the way it rode flat and smooth. It was wonderful. I've read a bunch about small jackplate adjustments and testing, but with my brief testing this weekend through the entire range of the plate slowly bumping it up and down and leaving it there for a period to see if it settles, it never settled, it continued porpoising. I didn't buy the digital readout though, since there's no available space in my dash for one, but I'm reconsidering that as perhaps a higher priority now. But the Atlas does have the yellow "tape measure" scale on it. It'll go as low as 1" and up to 6" or 7" (I don't remember off the top of my head right now).
I'll do more adjusting through the range again in a couple weeks (when I'm back at the lake). I'll also try to pull a measurement from the prop-shaft axis to the pad. But the boat sits in a lift over the water, so a little cumbersome to easily get measurements. In the past the only thing we messed with was trim when we wanted to go fast, which isn't often on our small 1500 acre lake. Plus I want it easy to operate for my Dad since it's at his lakehouse, and he NEVER goes much above 20-25mph, the annoying porpoising speed now.
Any other words of wisdom? Did I mess up by going with the hydraulic plate? I'm having a bit of buyer's remorse since it worked so well without issue before. Someone hold my hand, please. Goodness, I feel like a 45yo snowflake and I'm melting.
Last edited by boarder1995; 06-11-2018 at 12:34 PM.
My guess is the PPs changed your balance point. My FX21 will do the same as yours. I found that I have to run it up to about 4K rpms (the break over point), then start trimming down as I reduce rpms. Not perfect, but it does eliminate the majority of the porpoising. I don't believe changing your mounting hole will improve the performance. 2nd hole from the top is where most are mounted. I have seen a few in 3rd hole, but none in 1st.
Maybe I'll run the fuel tanks down real low and see if that changes it back to how it performed before. ~6.3#/gal x 20 gal at least = 126# that's way in the back. Remove that and I'll be close weight wise to where I was hopefully without the 2nd PP and Atlas JP weight. I'll resume testing then. But I do remember having the new Atlas on a little while before I installed the 2 new PP and filled the gas tanks (with just the Atlas being the only change) and it was porpoising then (jacked down and trimmed down all the way). Ugh. Should I not have stayed with the 10" setback?
So, being too deep with the prop won't necessarily amplify the porpoising?
Last edited by boarder1995; 05-30-2018 at 01:29 PM.
I'm having the same issue with a 2016 zx200 with increased weight. I added 36v tm and upgraded charger so increased weight of about 100 lbs to rear. I cannot get this boat not to porpoise below 40 mph. People try to tell me its "i don't know how to drive a skeeter" until they get behind the wheel. I've literally driven a bass boat thousands of miles and its not lack of driving ability. I'm actually going to add sand bags in the front compartments this weekend to see if that fixes the issue. Other than wedges i'm at a loss for solutions.
What are these wedges people refer to? They go between the jack plate and the hull to angle the motor down even more? To keep the bow of the boat planted more when barely on plane?
When I first got my FX21 (2012), I discussed this issue thoroughly with Skeeter. They assured me (for what that's worth) that the boat didn't do it without PPs. Their only solution, other than what I described above, was to add 3 degree wedges, which effectively adds more downward trim, but at the expense of loosing top end speed. Personally, I think the advantages of the HJP outweighs the downside of the porpoising, especially since I have found a way to manage it. I fish Sam Rayburn and Toledo Bend (FLW) and have to run some pretty rough water at times. The HJP is enormously beneficial in that circumstance. As mentioned above, work with redistributing your on board weight, and it will help some.
Well, today I added a CB Marine foil and it’s totally solved the porpoising issue. Perhaps it’s a bit of a bandaid fix, but with such weight placement sensitivity, I see it as “opening up a much wider weight placement window” type of device. It no longer porpoises, it gets on plane quick, and gets and stays on plane at a slower speed. I’ll post pics later. Got it in black with red VMAX SHO logo on both sides. Looks pretty stock.
Not that I’ve noticed. But mostly been testing holeshot, seeing if we can get it to porpoise, and how slow we can stay on plane. Will do some top speed runs today to see. But the foil should be out of the water when fully on plane running fast.
I kinda like that, where did you get it and how much, dont really have porposing issues, except the standard slowing down without trimming down first on all skeeters.
Motor is 2nd hold down from the top (ie.: motor has two more spots it can move up and only one more it can be lowered). I'm running a 25p T1 VMAX ventless prop, but currently on the hunt for a 23p T2. I can raise the Atlas enough where I'm non-stop blowing out the prop, so don't really need to go higher. See pic below for motor mounting location (I've got new dual PP Blades now too for some added rear weight).
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