Hull Blueprinting 22C

[Outboard Donzi]

Anyone ever worked with that buldge on what is supposed to be the pad on the inside lifting strakes? Makes me crazy everytime I look under the boat. What would happen if I made them straight? Would that make the profound porpose issues these boats already have even worse or are they the cause of them in the first place? Looks like a bunch of parisite drag at anything but full throttle. I never see anything like these on similar hull configurations.

[Trueser]

Do you have any Pictures?

The local guy here that blueprints bottoms says that its worth while.

Could be expensive.

[MOP]

Need to know if it is concave or convex? Should be concave between outer strakes, inner sounds weird should be flat. If it is convexed or usually can be straightened by heating the panel with heat lamps the jacking it just slightly past straight, how much is a judgment call to allow for a tad off spring back. 16's need tabs no matter what you do to them it is the nature of the beast. I got some good input on bottom blue printing from one of the more knowledgeable guys at Hustler, he says under 25 foot it is a waste. He feels that if you run in real flat water all the time there is a benefit but in chop there is very little unless the hull is really out of whack. If you watch a classic run there is not much in the water, maybe blue print the last 1/3 of the boat the rest would be just for S&G!

[Outboard Donzi]

Maybe I didn't describe the issue very well. I'll try to paint a word picture. If you kneel down on either bottom side of a 22 Classic, you can see the inner strakes have what the designers must have wanted to be a pronounced pad. Don't bother to look on the 16 fotter as it will not be there. I'm not sure if they used this mal-formation on the 18. It's an OE thing, not a blimish.

[Fish boy]

is this Bill?

[MOP]

As usual only half read the post! Having spent many moons sanding and futzing with my 22C bottom the aft section is and was dead straight eye balling from the stern. Post a pic if possible, like I said earlier panels can be straightened with heat and jacking into shape. Or you can fill, glass and fair, but I would try the heat first.

Phil

[RedDog]

... Don't bother to look on the 16 footer as it will not be there. I'm not sure if they used this mal-formation on the 18. It's an OE thing, not a blimish.

I've read your posts several times and looked at the hull of my 22 Classic and I can't see what you're talking about. Has someone added something to your hull somewhere along the way?

[Outboard Donzi]

That would be great if these are not supposed to be there. They sure do look OE to me though. My concern is chinewalk, if I remove the pad and just let the strake continue as it does from the front of the boat. So bear with me, your saying that if you follow the strake closest to the keel from front to back, you don't see it get wider towards the rear. That would make me very happy to see that other 22's don't have this appendege.

[Fish boy]

HEy Everyone,
I have been communicating with OB Donzi for a few weeks now about his boat and I am glad he decided to join the site. He does have a porpoise problem with his boat but hopefully some of you who have done substantial bottom work on the 22's will be able to make some suggestions.

He has done some really neat stuff with his boat, and after seeing pictures of it, I would love to make one too. It is very innovative especially considering what he started with, and with the right tweaking, cold be a fantastic boat. If you have a comment related to helping resolve the porpoise issue or the hull, your thoughts will be greatly appreciated (CDMA, HP600SC, Woodsy, Poodle, Brownie, MOP, anyone else that has been there done that and knows these boat inside out). Any suggestions?

Fish

[Outboard Donzi]

For getting some pics out there. This was a huge amount of work. I had many talks with myself before I finally decided on this radical transformation. I know everyone won't appreciate it. It sure does get a lot of attention when I take it to the water. The good news is, I already have two offers to purchase. It's not for sale at the moment.

[MOP]

So you started out with a 22C hull and made this little beauty, it does look real decent. I asked back a bit does the hull have a concave area aft? Is the porpoising just in a certain speed range? I have setup a few bracket boats that ended up doing the same thing, the cure was going to a stern lifting prop. With the engine set way back it has tremendous leverage and lifts the bow like crazy. This does not address the hull deformity but may be a starting point, need more input on hull thing.

Phil

[mattyboy]

I might not be has smart as those fellows but i think that boat has a different CoG now ,
where's the tank?? I would think that boat is lighter than a I/O 22c, that's the problem with a one of a kind, even Woodsy's boat is a lil different,
I wonder the hull has a deformity?? could it be a rocker hull??

[Outboard Donzi]

I appreciate the disscusion. I tried to be very careful not to change the CG. The tank was not moved and I tried to get the seating configured to be distributed the same as before. The setback and not enough prop (bow lift) will probably turn out to be the culprit but I will remedy this with a 4 blade custom prop which is being made right now and even more hp and rpms this winter. The hull has no rockers or hooks, it simply has some weird looking strakes the likes of which I've never seen. I'll blueprint this winter. The porpose goes away when I deploy the KPlanes and when I drop the hammer and retract the planes she climbs onto that weird looking pad and goes nicely. I just think the strakes are scrubbing off a lot of performance and I'm not sure they don't amplify the porpose. They sure look OE but one guy here said he didn't think his had than apendage on his 22c. I was worried that they were there to prevent chinewalk or some other handiling issue.

[Outboard Donzi]

After having explored a bit this site last eve, I believe there are several of you in my area. I'm writing from Victoria, Texas where I work and I also have a home in Houston in the FM1960 area. I look forward to seeing some of you when possible as I intend to bring the boat to Houston quite a bit.

[Fish boy]

OB DOnzi, any chance of getting some pics of the bottom? You can email them to me and I will post them for you if you want. Just curious if the guys that had the boat before you made changes to the bottom.

Hopefully CDMA will also report in since he did some hull design/engineering for Donzi in the past few years, and has a buleprinted 22c that he is building up.

fish

[mattyboy]

good luck and welcome aboard you'll get it ironed out don't forget to register your boat here, would like to see some pics of the pad?? I looked at the bottom of a 22 last nite and was padless,

[Outboard Donzi]

I'm still having problems attaching pics. It gives me a message "fatal error exceeds 360 seconds". I'm in the country and on dial up at this location, is that why I can't make it work? I'll send it to Fish if he doesn't mind doing my IT work. Fish, thanks in advance...Bill

[Fish boy]

OB Donzi, here is the pic of the bottom. Sorry you are having trouble posting. If you need any others posted and are still having problems, feel free to email them to me.

fish

[CDMA]

Wow I spent many hours under the bottom of my 22 project boat and I never saw anything like that. IMHO that is added.

On top of that I can't think of ANY possible hydrodynamic reason for wanting something like that on the bottom of your boat ( other then to slow you down). As bill said the only possible thought would be to counteract some form of handling vice. However after giving it more thought I can't figure any handling vice that would be helped by such an appendage. The flow in that region should be unidirectional and other then a very small boundary layer it should be completely laminar.

Chris

Hope all are well. Still bouncing around Europe. In St Tropez now and on to spain next. I will be back in touch late october.

Thanks to Fishboy for pointing this out to me. Though I would not say I did hull design for donzi I have done a little bit of that for other reasons.... ;)...not to mention laying under 22 Donzis...I am a professional at that

Miss all the events. :(

[MOP]

That is one weird bump! I would get out the grinder and get rid of it. That can not do much more than slow the boat down, I would borrow some stern lifting props maybe even a cleaver, your boat will be much more efficient using less tab.

Below an article on props may be of interest.
http://www.continuouswave.com/whaler/reference/prop3.html

P.S. Check your parts post!!!

[Fish boy]

Hey CDMA, glad to hear things are going well in Eurpoe. Miss ya around the boards and in sarasota this past weekend. Thanks for the input.

does anyone have a pic of a 22c bottom? I think I have seen a few restos where the 22 has been upside down when working on the bottom. If anyone could post one it would be appreciated.

fish

[Formula Jr]

OB Donzi,

That does not belong there. And you say they are on both sides?
The only reason I can think someone would put something like that on a hull is if they thought they were building in some sort of permenant wedge to bring the bow down. Or some sort of backing to run a huge lag bolt into. Hopefully the original bottom is still there under all that. Somebody spent time doing that, but they must not have been interested in a planning hull anymore or wanted some weird way to decrease the turning radius with all the drag those things would create. Don't know.....never seen anything like that before....

[ToonaFish]

I might not be has smart as those fellows but i think that boat has a different CoG now ,
where's the tank?? I would think that boat is lighter than a I/O 22c, that's the problem with a one of a kind, even Woodsy's boat is a lil different?

I'll make Matty feel like a rocket scientist with these questions!

How fast does it go on the GPS (or on the water for that matter!)?

Without a deck, per se, what happens to the aerodynamics of the boat? I realize, thanks to the Hornet/Sportsman designs (whatever happened with them?), that the surface below the water is of the greatest importance, but surely the deck would have some degree of influence?

It really is an interesting boat... and will be very curious to hear how removing the alien lumps effects your handling and performance.

Bunches,

Celene 'welcome to the wacky world of Donzi customization'

[BUIZILLA]

Looks to me to be a mount pad for an internal spigot depthfinder.


JH

[Outboard Donzi]

Thanks to everyone who weighed in on this subject. I am elated to hear that those bumps do not belong there. They do look OE and I was a little disapointed in Donzi for putting them there. I'll remove post haste! The GPS numbers are 59.9 with two people and 62mph with just myself. I used a lighter core material in the floor and weight should be distributed in a way that doesn't cause the bow to be heavier than before. These boats are very weight critical and if you want to boogie it's importanrt to be able to carry the bow pretty high. The numbers I posted are only going to get better as I am running a 3 blade 23p prop that cant lift as good as I would like. That will change as soon as I recieve my new 4 blade 24p. Some good news, the Gaffrig speedo is impressive in that in no-wind conditions it seems to be bang on with my GPS. I was humped up like a show dog over the speedo! I did a boat to boat video yesterday and I got a lot of visual info on the boat. I expect shes going to do much better without the bottom problems. Maybe 5 or 6 mph better. I'll report in when the Extreme makeover is complete. Thanks again for chiming in (no pun intended) I am staeting to feel at home here!

[Outboard Donzi]

By the way, can someone tell me what the stock speed of the 22C is supposed to be? I never even bothered to ask that question. Should be kinda important I think. Depending on setup I figure there will be several different speeds reported but I was also wondering what the stock advertised speed might be. I assumed the unit should be pretty drivable at 70 but then who knows, I haven't reached that point just yet...

[Woodsy]

hey Outboard!

WAY COOL BOAT!!! When you get a chance, give me a ring 978-502-5465 and we can talk about setups. My boat was setup way wrong at the last repower by the previous owner. I think you have too much setback... The most successful OB with a similar hull design is the 22 - 24 Superboat. Giver me a buzz and we can talk shop...


Woodsy Von Outboard...

[Outboard Donzi]

I'm not so sure that it's a bad setup. I'm working through the problems quite briskly. I love the clean water it gets. The problems are fading fast and the handling is surpurlitive for the lenght of the vessel. I am not bored yet. After I address the hull footprint issue I'll bet this baby will run with the best and on half the Horse Power. I do wish however that Santa would bring me a New Merc 275 Verado, and as I understand it, you are trying to repower sometime in the near future. That baby would book for sure. I'll be glad to call but you didn't leave a time window. I wish you could see the video I made this week, I'm not sure you would say wrong setup...Bill