ndaniels

Well, turns out the 21 Super I have is the only one that was made with the Blackhawk drive. Hearing about it from those that have rode/drove it, I guess it was a rocket with the stock 502 and bh.

Currently it has a built 509 with a stock bravo drive behind it. The propshaft is around 5-5.5" below the pad. I'm planning on replacing the lower with a imco -3 and modding the upper for prop clearance. The prop would be 2-2.5" below the pad. I think this should be a great setup, but have no ideal how it would compare to going back to a bh?

From what I've seen the blackhawks are around 12mph faster than a stock bravo- I don't think the speed difference would be that much compared to a -3lower on this boat? There are a bunch of things I don't like about the BH, like idling at 6+mph, no props, and worse rough water handling. I have no first hand experience with one... just what I've read. It would be a really cool drive, but I'm not so sure it'll be practical for the type of boating I do... and its quite a bit more than switching out the lower.

So, lets hear your opinions or thoughts on my drive dilemma? Or if you have a story about the boat, share it.

Thanks!

z.zuperboat

I dont think it can compare to the black hawk in any shape or form. The only down side will be the fast idle speed.

ndaniels

Thanks Zuper...
I posted this over on S&F and hearing about how the boat ran, sounds like it was realy flat... according to The Hoser who drove the boat- It wouldn't lift the bow and anything over 80 became uncontrolable.... on SB website there is a claim of 96, which falls right in line with the speed differences I've seen compared to a stock bravo- but that was on cats/pod tunnels...

Pat McPherson

It sounds like you have a good plan to me.
Start with the -3" lower and you can space it down if need be.
I would not raise the gimble and engine up and screw with the CG of the boat.

ndaniels

I have absolutely no hatch clearance in the 21, in fact its toucing it. I agree with keeping the COG as low as possible, espically with this boat (it already has aluminum heads, so thats a big plus). I figure drive depth should be just about right, but was looking for some opinions on it before dropping $s on the shorty case.

Thanks, Pat.

Pat McPherson

You could call up grumpy old John and asks him where he set the prop shaft on the new 21 I/O he built a few years ago.
I remember talking to him about how the newer 21 deck and engine hatch allowed for the "X" dim being higher.
Pesonally, I think you'll be good at 2-2-1/2" below but I'm not basing that on any more than a guess compared to some 22' Velocities I've read about. The Velocity has a much larger pad and a notch so some have run well with the prop even with the bottom.
As for the Blackhawk drive, I believe they only ran well on boats that had a rocker built into the bottom or boat that don't require any bow lift at all. The 22' Donzi Blackhawk had/has a lot of rocker cut into the bottom. The 22' Donzi Blackhawk does not run well in the rough compared to a stock 22' Donzi. Think about it, two props are going to lift the heck out of the stern and can create a lot of bow steer.

ndaniels

One of the first things I looked at when I picked up the boat was the bottom- its straight. I read alot about the dozi bh editions and rocker they added to em... had no idea what to expect when it came to the bottom on this sb.

I was thinking that the prop depth should be about perfect with the -3 lower. 2-2.5" should still allow for alot of leverage and hopefully reduce drag... could always add a neutral xtension box if its a little too high- that'd be really trick...

I'm kinda tempted to wait untill the middle of the season or next fall to do it, so I can get a good base line with the current setup... but know that I'd be better off catching Mr.Gadgets earlier than later.

Thats what stinks about buying a new boat going into the winter... I've never even run the damn thing, but have been kicking around ways to make it faster/better handling. Just looking at the drive depth, it looks way too deep to me- for such a small boat, and I can imagine thats going to be a problem as far as handling goes... wish it was spring already!

GRH

I drove that 21 with the blackhawk in original form.... 502 Mag 415HP.... at the time it had the biggest blackhawk props, cleaver style, available.. 30's maybe? and it would bump the rev limiter.....

Anyway... with 4 adults it ran mid 80's effortlessly on the speedo... and you could take your hands off the wheel it drove like it was on railroad tracks.... I can;t imagine why anyone would have changed that drive?

If you can find another blackhawk... put it back.... I would have owned that boat if the guy had been the least bit reasonable about selling it....

I bought the 24 you have Nick instead.... seems we have the same taste in boats & its great that they both ended up with the same owner!


Enjoy & have fun with them.....

Gary....

ndaniels

Hey Gary... man, you have great taste in boats!!!!

Its pretty funny that you looked at the 21- I'm guessing it was owned by the guy in CT when you saw it? If so, he is the one that replaced the drive with the bravo. I've heard mixed reviews about the Blackhawk. I'd love to have one to give it a try and see how I like it. There is one up for sale right now, but its $pendy. I don't like how hard props are to come by on the BH. Guess I'll keep thinking about it.

I was going to send you an email this spring to see whats been going on... still have the Y2K? Hows it been treating you?

FX10

While at the shop with Sean, George and myself, I asked Coen about your boat. He said it did a solid 92 on the rev limiter. And it was set up perfect. At least thats what he said.