2Slow4me

My brother has a 1990 22’ Donzi Z-21 (not the classic, forgot the actual model, the one that looks more like an Italian boat, very sharp)

And he has just put in a 550 HP motor, from the stock 330 454, and this thing proposes like crazy, you can put the tabs down and it will hold, but feels terrible.

I think the drive is too low, and an Imco Shorty would make a significant difference (especially in the speed department)

Any suggestions??

Thanks in advance

P.S. The motor is new, so not had many props to play with yet, the current one (just got it) is a Michigan 25" prop

2Slow4me

Looks like this one:

http://adcache.boattraderonline.com/6/3/0/89720630.htm


Hornet

Payton

Maybe the drive and\or prop. First I would put at least a 4' straight edge on the hull to see if you have a hook. Your's sounds just like what mine did before I found an 1/8" hook in the last 4" of hull. It was very easy to sand out.

bowtie

Take that motor out and put in a small block and your problems will go away. I have one I'll trade even up if your brothers interested.

Scott B

Wrong..

The 22's porpoise.. At higher speeds the porpoising will go away with time and experience on the trim switch, but 35ish to 5oish she will want to bounce. A lot Props make a huge difference on that hull, what are you running now??

Shorty will eliminate a lot of the bow lift capabilities of the boat, but propped right it will be fine..

For now, your brother needs seat time and also to play with props..

Do some searching around on Donzi.net for quite a few threads on the handling of your boat. God info, good group of folks who can and will hep you get it dialed in..

2Slow4me

Model is the Z-21

The motor is new, so not had many props to play with yet, the current one (just got it) is a Michigan 25" prop

BadDog

I would bet that it is the prop. I would bet that you need a prop that carries the bow better, something along the lines of a Mirage Plus. What happens with the orignal prop spun up to redline? Does it behave the same as before?

Scott B

Go 4 blade on that hull...