21PHX Chine at 73

[starkcontrast]

Ok boys, first off, I love my Bird. I came out of a Ranger Barn Door and my lower back has been thanking me for the upgrade to the Bird ever since. I've had some seat time now and have made some hot runs in the 21PHX. I'm running a 250 SHO on a 10" Atlas Hydraulic Jack plate with Talons. I'm running a 25p 4 blade Fury. Water temps were at or around 49.

On a half talk, empty livewells and a modest tournament load, I was able to get her up around 72 without a hitch. The SHO likes to run with the jackplate high, I've found. In fact, all of my best speeds have come with the plate maxed out to the top (20 on the meter).

As I am running with the jackplate up and gaining speed, I am trimming up slowly, but no matter what, I seem to encounter a chine at around 73. That being said, I have seen 74.8 by steering through it, but I know guys claim that they don't get any chine with the 4 blade Fury. What do I need to do different (besides slow down) to get the maximum performace out of this glitter sled? Thanks in advance.

[Tom Edwards]

What is the PTP?

What holes on the jack plate is the motor mounted to, upper or lower? Depending on whether or not there is more than one pattern of holes on the jack plate for the motor to mount to.

[Cfrench085]

Mount motor one bolt hole higher I would say come up on the plate but you’re already at the top.

[vausoner]

When your plate is all the way up what is your p2p?

Once you feel the boat starting to get loose make small little jabs with the steering wheel to the left and it will balance the boat on the pad. To get everything out of it you will need to "drive" the boat a bit. You can play with your load and balance everything from left to right but when you get up at that speed you will need to drive it a bit.

[starkcontrast]

I have not had someone to help me accurately measure it. Besides, I feel like the PTP height doesn't matter as much if you have a hydraulic jack plate because you can move it on the go. Am I wrong? I mean, maybe I just need to bump my trim down when she starts to walk and be happy with what I am getting with a 4 blade prop.

[Tom Edwards]

You ALWAYS need to know the PTP for an accurate assessment of what is going on.

And one person can do it alone.

[vausoner]

Like Tom said its always good to know what's going on p2p wise when you're running and trying to set up a new boat. If you were used to having to control the walk it wouldn't matter so much because you can feel it in your butt so to speak where it wants to be and when you need to start correcting it before you get out of control. Every one of our boats will walk if we let it. They are definitely not point and shoot.

[HTC33]

Dam....that’s a good top end on the 21PHX. Best I can do is 73ish; which is pretty similar to what others are getting

[vausoner]

Everything else aside, they are good numbers though.

[Tom Edwards]

Oh ya, how much chine? Slow and smooth with just a little/moderate rise and fall of the gunnels? Or violent chine that tries to throw you out of the boat, and whips the boat sideways and tries to flip the boat? Slow start of chine? Or immediate violent chine with no warning?

[xranger77]

I would move the motor if you are topped out on the plate. I had chine on mine at 74/75 alone, (921XP with a Verado) and was maxed at 20. Boat wanted to keep going as I felt.

Moved the motor one hole and gained some speed and lost the chine. I moved it again and now have room to moved the motor on the JP and it rides and drives much better overall. I picked up 3mph on my fastest run as well. Not saying yours will do this, but moving the motor gave me flexibility in the plate range and have no issue running 74/75 loaded and its easy to drive.

[limitout]

Chine walk on a 21 PHX I didn't think that was possible as you can drive that boat with one finger it's so easy to drive. If 73 MPH you are doing great as I couldnt get my SHO combo over 72.

[duncankopprichardson]

Mine acts the same way. Just need to correct it with the steering as stated above.

[duncankopprichardson]

With a Pro XS and 3 blade it should be a 74 mph boat. Your probably at your top end with a 4 blade.

[Cnorm129]

Got a Pro XS with Fury 4 and can only get 73 out of it. Most i have heard of was 75 with a 21 PHX.

[gatorsin09]

Fury 4 on my 18 921 PHX. Chine only happens when i trim uo before im up to speed or have the jackplate too high or low. 74 alone and loaded. 73 with a coangler loaded

[Fidgetcranker]

I would say you're running about right.
You can move the motor up a hole to gain a little JP room.

My 921xp/sho chines at about 70-71. I'm running high and throwing a big rooster tail.
I know cowl high rooster is recommended, but my best speed is with a high one, 74.9mph
My p2p is high, between 2.5"-2" while also trimmed to the max.
I'm not "chopping" the prop blade (T1-25 worked), but real close.
I know there's others on here that throw a high rooster with the sho for speed, some don't need to.
Just watch your water pressure close. Don't let it drop too much.

It boils down to learning to control the chine to hit optimum speed.
As you do you'll be able to max out boat's performance.

[dstep0]

Sounds like you need to move the motor up a hole or so as stated above.

[starkcontrast]

Oh ya, how much chine? Slow and smooth with just a little/moderate rise and fall of the gunnels? Or violent chine that tries to throw you out of the boat, and whips the boat sideways and tries to flip the boat? Slow start of chine? Or immediate violent chine with no warning?

No, it is definitely slow and smooth. I can drive through it no problem, but I was under the impression it could be eliminated all together with the 4 blade Fury. When I was running a three blade T2, I saw 76 but the chine was a bit more pronounced.

[Wackyjig]

No, it is definitely slow and smooth. I can drive through it no problem, but I was under the impression it could be eliminated all together with the 4 blade Fury. When I was running a three blade T2, I saw 76 but the chine was a bit more pronounced.

You're scootin with a 4 blade. I doubt you'll be able to get rid of all of the walk. You might do as suggested and raise the motor a hole but I'd check your p2p with your jp all the way up first.
Hows the holeshot with that prop btw and what rpm are you turning it to?