Porpoising - 22'Classic

[slapshot11]

My 22' Classic seems to porpoise more than it should even on relatively calm waters. I run fully trimmed in whether I'm alone, with one other person or even 4 adults. I'm still new at this so it may just be a matter of seat time. Will tabs help or is it a prop issue? I'm running a Mirage Plus 25P on a Bravo 1 with a 502 EFI. It's particularily bad at 3,000 RPMs and gets better the faster I go. All gone at WOT. I searched various previous threads and suggested props seem to be the Turbo 1 22" or Hydroautomotive QIV. But which one is best for a 22?

[Pismo]

I have the same setup, 502 Bravo I 25" Mirage Plus on a 22 Classic and I am always working against the porpoising. Tabs down some will stop it dead but then you get the "tabs down" feel, ie drag, drag, roll, etc. A touch of tab seems to be enough and doesn't give you the "feel". Trim fully down also stops it for me, which is negative on a Bravo. Up even a little and it starts to oscillate. I usually run under 3000rpm/40mph. Gone by 3500 and above. I wonder how the old 22s with TRS drives, where fully down trim is neutral, behaved? My boat at neutral/straight back trim will most definitely porpoise, I need negative to stop it. The engine forward a foot in the TRS setup may have helped. Full gas tank seems to make little/no difference. I hear the Turbo 1 25" is the answer, have not tried it. Until then, trim fully down and a touch of tab as last resort stops it, or more speed. The hull is built to go 65mph, not 30mph, and it does so beautifully.

[Dr. Dan]

:bonk: FWIW..My King Cobra has never had a porposing problem, I started with wa 23 pitch Turbo 3 Blade. Ran it for 4 Seasons...never an issue. Upgraded to the 25 Pitch after the Repower...still fine, this year we will be dialing in a 27 Turbo. Ran it a little this past Sunday ...and no issues..

I think the Turbos work well because they have the right amount of lift,slip and diameter for the 22 Classic Hull. I also know the Hydro 4 Blades work well also. I think its more seat time, experiment with your Drive Trim, establish Nuetral Position on your Drive Trim indicator...and experiment from there...if you don't know where your Drive is in full Nuetral (Cav Plate Parallel to Keel RunningSurface), you are likely over Trimmed for the running speed at which the Porpose begins....take notes, have someone record your info, if it helps..but its really more seat time...

Try a Turbo...I think you will find its characteristics are better suited for your needs. I would guess a 25 Pitch should be about right...maybe a 24..

Good Luck

Doc :shades:

[Rodger]

I have an older 22 with the TRS. The drive all the way down will prevent porpoising. Above 32 or so MPH I can bring the drive up slightly, and in most cases, the porpoising will not be noticable. At very fast speeds I can trim way up. I use a Mirage prop.

[boldts]

Had a 98 22 Classic that came with a 23" Mirage on the Bravo1. Stock 454MAG engine and 1.35 drive ratio I think. Boat had a ProCharged engine before my purchase, thus the drive ratio change from the usual 1.50 ratio that most have from the factory.

Mirage porposed at all speeds but wide open. Didn't matter where the drive trim was. Kiekaffer tabs would stop the porposing, but as stated by others, it tended to bury the bow if tabs were used to heavily.

At the suggestion of 22 owners who had tested and run the Turbo1 props. I bought a 23" Turbo1. Boat was perfect from that point on except due to my drive ratio, I needed 1" less pitch. The 22" Turbo1 optimised my set-up. Boat went from 65 on GPS with the Mirage to 68 on GPS. Best thing was the boat was now drivable at any speed without porposing and was a joy to drive!

I learned at AOTH this year that Precission as made a few changes to the Turbo1 prop. I do not have any new prop data to offer anyone as to it's performance on the 22 hull. They are pushing the TXP prop and from what I've heard, the prop works well also. To contact Precission - http://www.turbo-props.com/ ask for Chris Booh (Boo) Chris experienced the Classics at AOTH and can help you get the right prop for your Donzi.

[undertaker]

I am curious Chromegorilla has a 25 pitch mirage prop on his 05 22 classic, do you have a porpose problem Chrome??? :cistineb: I am a serious newbie to the 22 classic scene so I am just a little curious.

PS I know seat time is VERY important in the 22 classic. :biggrin: :biggrin:


Underboy :fire:

[RedDog]

I have the same setup as Slapshot and Pismo. I put a 25" Turbo I on ths year to replace a 25" Mirage Plus. The porpoising is a little better but is definitely still there. Dropping the tabs at at the mid range speeds cures the problem. I can raise them as the speed increases.

[Woodsy]

Sounds to me like a case of "Classic Overtrim" Pun intended... LOL!

At 3000 rpm you should be using a little trim. Trim should be gradually increased as your speed increases to help air out the hull. The easiest way to explain how to trim out a 22 classic is this....

1. Get to what ever speed you want to cruise at, be it WOT or 3000 RPM without using the trim... AT ALL!

2. Trim up until you feel the boat loosen up. You will actually feel it go faster.

3. If you over trim at this point, the boat WILL porpoise.

Just because there is a trim limit, it doesn't mean you should be on it at all RPM levels

PS: All bets are off if its Blackhawk hull.... LOL!


Woodsy Von Outboard

[Dr. Dan]

:smash: Woodsy the Resident Engineer has Spoken...so he is alive up there!

Doc :uzi:

[RickSE]

My boat will porpoise from the get go even with the drive all the way in, Labbed 25 Mirage+ with some unknown :confused: raised X-Dim. I love the Mirage+ for WOT runs but hate it for cruising. I really wish the factory would do the homework and figure out the best all-around prop to put on these boats. They have the best resources. I'm sure we'll never see anything other then a Merc. prop on a new Donzi though. I did list the porpoise as a complaint on my survey card.

Now you know why tabs are standard equipment on all 22C's and options on the 18C and 16C.

I've yet to try anything else. Waiting for you guys to figure it out first. :biggrin.:

[slapshot11]

Thanks everyone for your help. My plan from here is to play with the tabs this weekend and keep my eyes open for a Turbo 1 prop. :)

[BigGrizzly]

Slap shot now that you are using My picture you need to drive a boat with the right prop and that Marage is not it. If you check out our history every porposing 22 had that prop on it. That prop isn't a bad prop it is just not a good one for that boat, Now if you had 2 400 pound people in the front it may slow the porposing down a bit. I'm not saying this just because I am a Turbo dealer but i can always fix most of that problem by leaving that prop on shore. At the speed at which I travel the prop handling is where it is at.

[TOPSY II]

BigGrizzly: My '86 Minx has the same porpoising issues...Woodsy's narrative on "the fix" for his 22 is EXACTLY what I have to do with the Minx.

Where are you located, ( I'm in Vinings Area of ATL), would like to pick your brain on 3 vs.4 blades..pitch/diameter "the whole enchalada". I've also experienced some of the Roll that George experienced, but thankfully without my bride in the left seat!! and not at the extremes he experience at Cumberland...but I'm convinced the narrow beam makes messing with the tabs a VERY delicate operation...but I'm learning..just tapping them, sometimes in opposing directions is enough...trim as well has a learning curve, as does water conditions, chop, smooth, quartering wakes etc....you name it, is DOES affect the handling!

TOPSYII :propeller

[TMANN]

Mine porposed real bad with the Mirage 25p that came with it. Then I got a 24P Turbo and will never look back. It was like night and day for me. I love the Turbo!!! I have a 454Mag if that helps.

TMANN

[pmreed]

Similar set-up, '99 22 Classic w/502. Came with the 25 P Mirage +. Fun prop, and I could stop it propoising at cruise by tucking the drive way down. Flat out was where it was fun; put the hammer down and keep trimming up 'til it flies. Watch Chromey's avatar for the look. Fun, but loose; and it had a tendency to chine walk passing through the high 60s. You really had to pay attention, as you were on the edge. Put on a 25 P (now a 26 P) Turbo and the handling became benign. Much less tendency to porpoise and no significant chine walking. Flatter ride at speed and just as fast. If you get a chance to try one, do it; you won't be sorry.

Phil

[joseph m. hahnl]

Similar set-up, '99 22 Classic w/502. Came with the 25 P Mirage +. Fun prop, and I could stop it propoising at cruise by tucking the drive way down. Flat out was where it was fun; put the hammer down and keep trimming up 'til it flies. Watch Chromey's avatar for the look. Fun, but loose; and it had a tendency to chine walk passing through the high 60s. You really had to pay attention, as you were on the edge. Put on a 25 P (now a 26 P) Turbo and the handling became benign. Much less tendency to porpoise and no significant chine walking. Flatter ride at speed and just as fast. If you get a chance to try one, do it; you won't be sorry.

Phil


porpoising is the inabilty of the boat to stay planed out.especially when the power trim is set to high.

[BigGrizzly]

TopseyII I live on Taylor Creek up by Warhill park.I will be there this weekend if you want to pick a brain. that goes for you too Dave. My boat hasn't been in the water since October and this is my weekend. One of our Japanese engineers from Honda Marine will be there Saturday morning for me to give a ride so he can understand what Marine speed is really like above 70.

[CMC]

Hey Guys, I tested a 2003 22 Classic yesterday. The boat had a 496 mag(375HP) and a 3 blade 25 mirage. First when getting on plane the prop began to slip, then when on plane came the insane porpusing started. The owner said that the boat came with a 23P but would always hit the rev limiter at WOT. Therefore he switched to the 25P, but now had these issues. He said the drive must always be all the way in and no tabs when taking off. We tried again and although it was better, there was still some slippage and porpusing. I totally believe the owner but there must be some solution to this problem. Does any one ust the 25P and experience these problems. I have done a search here, and gone over all the posts. Will a 23 or 24 3 blade TURBO really solve these problems? If I were to call DONZI, which prop do you think they would recommend. I know seat time is needed, but any help or comments would be great. When you buy a new Donzi 22 Classic, which prop does the dealer give you?

[ChromeGorilla]

My 2005 22 came with a 25P Mirage Plus and i think it is matched pretty well with the boat/motor combo (496HO). My boat needs at least a little tab at all times no matter what you do with the trim. If I don't have any tabs down my boat will porpoise like crazy up to about 55MPH. Also with the drive all the way in is a crappy ride for me...need a little trim... The only time I can pull the tabs all the way up is WOT.

[bob haver]

My 22' Classic seems to porpoise more than it should even on relatively calm waters. I run fully trimmed in whether I'm alone, with one other person or even 4 adults. I'm still new at this so it may just be a matter of seat time. Will tabs help or is it a prop issue? I'm running a Mirage Plus 25P on a Bravo 1 with a 502 EFI. It's particularily bad at 3,000 RPMs and gets better the faster I go. All gone at WOT. I searched various previous threads and suggested props seem to be the Turbo 1 22" or Hydroautomotive QIV. But which one is best for a 22?
Something for you to consider. I am not running the usual prop on my 22 classic, I spoke with Ron at Merc racing, in the prop division, and told him I was running a mirage 25 with a 502 mpi stock. My speed prior was 74 mph at 4950 rpms with relatively no chine walk. Based on Ron's reccomendation, in the spring I purchased lab finished 26, 4 blade 14.5 diameter, and my results were 4975 rpms, 76.8 mph, no chine walk, boat came out of the hole better, but did increase torque steer. Overall very happy with it. This is a bravo prop, some of the guys in the local Donzi Club couldn't believe how well the boat performed.
Good Luck
Bob Haver

[CMC]

What is it about the TURBO prop that makes the differance? What about the prop slippage, what could be causing that? It happen when punching the throttle to get on plane. Has anyone been hitting the rev limiter with a 23p mirage? Thanks

[boldts]

C - My post kind of gave you an example of how the Turbo1 I purchased helped slippage on my application. The mirage 23 that came with my boat had a larger diameter than the Turbo1 prop so I figured lets start with a 23" Turbo1. Upon testing, even though the Turbo1 had less diameter, the 23" was still only turning 46 or 7 thousand rpm. That is why I sent the 23" Turbo1 back and received a 22" for my boat. It was perfect from that point on. WOT was right at 48 - 49 hundred rpms and the handling was beautiful!

Point to story is that I actually ended up using a smaller pitch Turbo1 because the slippage was decreased.

If you haven't yet, call Chris at Precission Propellers. He may suggest the TXP over the Turbo1 and from reports here, it may be an even better prop for the 22 Classic.

[boatnut]

Interesting thread. I just got a 22 Classic ('97 with 7.4L/Bravo 1/carb/supposedly 300hp??). I haven't had time to do some real measuring but when I was buying it I got close to 62mph on GPS (the prev owner thought it was doing 69+ but that seemed optimistic for 300hp in a 22??).
It has the porpoise condition many have described -- under about 3500 the drive needs to be trimmed all the way in and even then it will break into slight porpoiseing at times. I'm not sure what prop it has, it is labled "Bravo 1" is a 4 blade and has a p/n 48-831916 28P --- 28 seems like a lot of pitch so I need to get out and plot a speed/rpm curve soon. Is this prop the one everyone refers to as a "Mirage" or is it a different Merc prop? Thks, Ed

[Dr. Dan]

:bonk: IMO that is too tall of Prop for your Baby, need more info...whats your RPM's at WOT? What Gear Ratio do you have in the Drive? check out the prop calculator here - http://www.boatpropellers.com/propcalc.html

This is a great Tool to gauge some alternatives, even if ya use a general or conservative Slip Percentage...say 10 to 12%?

Good Luck

This is the Fun Part

Doc :wink:

[gold-n-rod]

I'm not sure what prop it has, it is labled "Bravo 1" is a 4 blade and has a p/n 48-831916 28P --- 28 seems like a lot of pitch so I need to get out and plot a speed/rpm curve soon. Is this prop the one everyone refers to as a "Mirage" or is it a different Merc prop? Thks, Ed

That's a Mercury prop. I agree that it's prolly too much prop for that boat. Time to try some different ones.

[slapshot11]

I just replaced the 25" Mirage Plus on my 22' Classic (1999 - 502 - Bravo 1) with a 25" Turbo which I purchased from MP. I have to say, it's a whole lot better. Much, much better. Still a little bit of porposing but nothing like with the Mirage. It was definitely a good investment. The Mirage is now my spare prop in the box. Thanks for the help MP.

[RickSE]

CMC, Prop blow out seems to be normal with a big block 22-C. It's cavitating the prop due to the power. Just feather it up on plane then give it the juice.

Slapshot11, What kind of RPM & speed changes did you see in switching from the Mirage to Turbo? I'd assume the Turbo gave you more of both.

[joseph m. hahnl]

my minx "rooster tail" with 21p mirage 350 mag .I run the power trim all the way down at cruising speeds . use the trim tabs to force the bow down in the chop. @ wot no tabs power trim up till she breaks loose . .some times I will keep the tabs down and then trim up to get more cavitation and build more rpm at cruise.

[Bad-Tat]

Porpoise??? Come for a ride with me if you want to see porpoise!! Standard 22C don't propoise a bit!!!

[barrukis1]

Why are all bets off if its a blackhawk??? Just found and purchased one. Notice allot of porpoising above 2300 but i chalked it up to lack of seat time. Is this a big problem with this 22. Im new to the site, so any advice would be appreciated.

[Woodsy]

Blackhawks have ALOT of rocker built into the bottom aft running surface of the hull. So much so that you can actually see it. Essentially your running surface is shaped like an egg. This rocker was bulit into the hull to help with bow lift as the Blackhawk provides very little. While this design works great at WOT, it is not so good at slower speeds and causes some serious porpoising. You will need to use your trim tabs to control porpoising at slower speeds, then gradually raise them as you go faster. There are few others on the site that have that down to a science.

Woodsy

[barrukis1]

Im getting a little better at it, but I've only been out a few times. She is a handful mid range but nice aired out. When I'm just cruising at at 2100 approx 30 mph, she rides nice with just a little tab and just under a 1/4 trim. Takes the slop nicely. I'd like to be able to run around 40-45 without porpoising and without the drag feel from bringing the outdrive in and dropping the tabs. Any thoughts to going to k planes like on the newer special edition?