New (to me) Donzi Z-24 w/ BBC @490hp - what 1st prop?
#1
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From: Chantilly, VA
I'm having a tough time finding "larger" pitched props for reverse rotation OMC drives. My boat is getting a new engine and I need to start figuring out the best prop for the boat, it's technically a Black Widow 24 but most are familiar with the Z-24 name that was more commonly used later on. I know there are many variables, but unfortunately with the reverse rotation and the (rather high) hp for an OMC setup, I can't go up to a marina and expect a good selection. The new motor put out just under 500hp dyno. I was thinking a 26" 3 blade, but that would probably give me a crap-tastic hole shot - boat does have trim tabs. It came with a 21p 3b Viper and the guy said it was in the 70s w/ a BBC Gen VI, holley 800, stainless marine headers, etc - but at that pitch I call BS.
From Solas I see I can get either a Titan 3 24p or a Titan 4 25p in left rotation. For cruising the Titan 4 would be great, and with the larger pitch I almost wonder if top speed would suffer at all over the 3 blade.
Most of what I do will be cruising, short top-speed runs, and (least likely) some water sports and hole-shot stuff, coming out of frequent no-wakes, etc.
Application is usually listed as 19 spline Volvo SX / OMC King Cobra (this is the later model King Cobra w/ cone clutch and F-N-R gears in the upper)
A friend at work has a brother who just picked up a 25' Nordic and apparently he's hitting mid-70s at low rpm (4700 I think, maybe less?) with a 26p 4 blade w/ stock 496ho?!
Seems like a lot of prop and boat to push w/ stock 496 though - so now I'm all confused.
From Solas I see I can get either a Titan 3 24p or a Titan 4 25p in left rotation. For cruising the Titan 4 would be great, and with the larger pitch I almost wonder if top speed would suffer at all over the 3 blade.
Most of what I do will be cruising, short top-speed runs, and (least likely) some water sports and hole-shot stuff, coming out of frequent no-wakes, etc.
Application is usually listed as 19 spline Volvo SX / OMC King Cobra (this is the later model King Cobra w/ cone clutch and F-N-R gears in the upper)
A friend at work has a brother who just picked up a 25' Nordic and apparently he's hitting mid-70s at low rpm (4700 I think, maybe less?) with a 26p 4 blade w/ stock 496ho?!
Seems like a lot of prop and boat to push w/ stock 496 though - so now I'm all confused.
Last edited by EstorilM; 03-25-2012 at 10:29 PM.
#2
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From: Boca Raton, FL
The Nordic Rage has always been a very fast boat...Alot of factors such as how high the drive is mounted, a stepped hull and relatively light weight contribute to the mid 70's speed. Dont get too confused trying to compare other boats to yours...
#3
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I'm having a tough time finding "larger" pitched props for reverse rotation OMC drives. My boat is getting a new engine and I need to start figuring out the best prop for the boat, it's technically a Black Widow 24 but most are familiar with the Z-24 name that was more commonly used later on. I know there are many variables, but unfortunately with the reverse rotation and the (rather high) hp for an OMC setup, I can't go up to a marina and expect a good selection. The new motor put out just under 500hp dyno. I was thinking a 26" 3 blade, but that would probably give me a crap-tastic hole shot - boat does have trim tabs. It came with a 21p 3b Viper and the guy said it was in the 70s w/ a BBC Gen VI, holley 800, stainless marine headers, etc - but at that pitch I call BS.
From Solas I see I can get either a Titan 3 24p or a Titan 4 25p in left rotation. For cruising the Titan 4 would be great, and with the larger pitch I almost wonder if top speed would suffer at all over the 3 blade.
Most of what I do will be cruising, short top-speed runs, and (least likely) some water sports and hole-shot stuff, coming out of frequent no-wakes, etc.
Application is usually listed as 19 spline Volvo SX / OMC King Cobra (this is the later model King Cobra w/ cone clutch and F-N-R gears in the upper)
A friend at work has a brother who just picked up a 25' Nordic and apparently he's hitting mid-70s at low rpm (4700 I think, maybe less?) with a 26p 4 blade w/ stock 496ho?!
Seems like a lot of prop and boat to push w/ stock 496 though - so now I'm all confused.
From Solas I see I can get either a Titan 3 24p or a Titan 4 25p in left rotation. For cruising the Titan 4 would be great, and with the larger pitch I almost wonder if top speed would suffer at all over the 3 blade.
Most of what I do will be cruising, short top-speed runs, and (least likely) some water sports and hole-shot stuff, coming out of frequent no-wakes, etc.
Application is usually listed as 19 spline Volvo SX / OMC King Cobra (this is the later model King Cobra w/ cone clutch and F-N-R gears in the upper)
A friend at work has a brother who just picked up a 25' Nordic and apparently he's hitting mid-70s at low rpm (4700 I think, maybe less?) with a 26p 4 blade w/ stock 496ho?!
Seems like a lot of prop and boat to push w/ stock 496 though - so now I'm all confused.Also a Nordic can run pretty good with a 496. A lot newer tech then the black widows.
#4
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From: Chantilly, VA
If its a king cobra type drive I would put a bravo drive in it and then worry about prop. They fit in the same hole. Why do they run reverse rotation on a single. Or do you have counter rotating props? I know props for omc etc drives are impossible to get since they are no longer made.
Also a Nordic can run pretty good with a 496. A lot newer tech then the black widows.
Also a Nordic can run pretty good with a 496. A lot newer tech then the black widows.

parts are impossible to find, not props - and that's mostly for the OMC Cobra and dog-clutch units. The model in my boat has more in common with the Volvo drives than anything else (most of the expired volvo patents went into the drive creation, and volvo purchased the rights back when they went under). Turbo makes a left-hand 26 as well I think, haven't verified application.
I have no idea why it was a left hand boat - it's a single engine and from what I understand, that's just how Donzi / OMC ran them back in the day.
Also, I know Nordic has fast hulls - but I don't think that boat has a step and their designs haven't changed much - Donzi hull design wasn't exactly the worst either

Anyways, I think if we lined up I'd do okay - but I certainly need to choose my prop wisely. Honestly I mentioned the nordic so someone could chime in on the prop choice on that boat and how the 4 blade has that kind of top-end, and if that's a prop I should look at for my 24'. He did mention it bogs down coming out of the hole and took a while to plane. Sounds like a smaller pitch 3 blade would probably give him similar numbers/performance and land him at a higher RPM?
Last edited by EstorilM; 03-25-2012 at 11:41 PM.
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Sorry man, I'm sure that would be "easy" but why just randomly toss thousands out the window when i've got a perfectly functional drive that's rated at 600+ hp? Plus the new motor goes in next week and that's painful enough on the wallet! 
parts are impossible to find, not props - and that's mostly for the OMC Cobra and dog-clutch units. The model in my boat has more in common with the Volvo drives than anything else (most of the expired volvo patents went into the drive creation, and volvo purchased the rights back when they went under). Turbo makes a left-hand 26 as well I think, haven't verified application.
I have no idea why it was a left hand boat - it's a single engine and from what I understand, that's just how Donzi / OMC ran them back in the day.
Also, I know Nordic has fast hulls - but I don't think that boat has a step and their designs haven't changed much - Donzi hull design wasn't exactly the worst either
Yeah I was actually trying to get that exact boat (Nordic mid cabin) but decided to pay cash for something I could flip and make some money on - I practically stole the Donzi so it's a good investment, even if I sell the thing in the fall. I was also looking at a Nordic Sprint. In the end my bank wouldn't touch anything more than 4 years old as well, so I started having to look around, ended up being a PITA.
Anyways, I think if we lined up I'd do okay - but I certainly need to choose my prop wisely. Honestly I mentioned the nordic so someone could chime in on the prop choice on that boat and how the 4 blade has that kind of top-end, and if that's a prop I should look at for my 24'. He did mention it bogs down coming out of the hole and took a while to plane. Sounds like a smaller pitch 3 blade would probably give him similar numbers/performance and land him at a higher RPM?

parts are impossible to find, not props - and that's mostly for the OMC Cobra and dog-clutch units. The model in my boat has more in common with the Volvo drives than anything else (most of the expired volvo patents went into the drive creation, and volvo purchased the rights back when they went under). Turbo makes a left-hand 26 as well I think, haven't verified application.
I have no idea why it was a left hand boat - it's a single engine and from what I understand, that's just how Donzi / OMC ran them back in the day.
Also, I know Nordic has fast hulls - but I don't think that boat has a step and their designs haven't changed much - Donzi hull design wasn't exactly the worst either

Yeah I was actually trying to get that exact boat (Nordic mid cabin) but decided to pay cash for something I could flip and make some money on - I practically stole the Donzi so it's a good investment, even if I sell the thing in the fall. I was also looking at a Nordic Sprint. In the end my bank wouldn't touch anything more than 4 years old as well, so I started having to look around, ended up being a PITA.
Anyways, I think if we lined up I'd do okay - but I certainly need to choose my prop wisely. Honestly I mentioned the nordic so someone could chime in on the prop choice on that boat and how the 4 blade has that kind of top-end, and if that's a prop I should look at for my 24'. He did mention it bogs down coming out of the hole and took a while to plane. Sounds like a smaller pitch 3 blade would probably give him similar numbers/performance and land him at a higher RPM?
If his hole shot is lacking that is the norm. What you gain on top with a good top speed prop you will lose down low. Plus most of don't do hole shots as its really hard on our drives and not really the function of our boats. It's mainly take it easy get on plane and then go.
Him going to a 3 blade might actually be the fastest prop but he will actually lose acceleration to the 4 blade but we would need to know a lot more about set up. Props are always compromises. It would be nice to see if Greg at cutting edge could cast you a custom prop with your hub. He actually makes props and might be a cool project. His props are amazing.



