Black Hawk outdrive

[Rocket-J]

I am looking at buying a 21'tunnel with a Black Hawk drive. The boat does over 75mph but is slow out of the hole. Is this just a prop thing or a characteristic of the Black Hawk drive? Can I water ski with this outdrive?
Any pros and cons on this outdrive is appreciated. Thanks. Al

[HavasuDreamin']

All propellor driven tunnels cavitate out of the hole...........it is a characteristic of the tunnel bottom design. This is why the Allison Drag Boats are so successful on the O/B drag circuit, (V-Bottom = NO Cavitation). I have never had any experience with a Black Hawk Drive, but I do know that it is a surface piercing drive and thus I would expect it to cavitate even more than say a standard bravo due to the white wash water near the surface. If the boat is solid and you like it, and can deal without pulling skiers, I would say go for it. In my experience no tunnels pull skiers well. Good Luck.

[stressedout]

Without knowing what hp it's running , it's difficult to say why it's slow out of the hole.The drive is no longer made. I can tell you I know of three boats running this drive. One of them runs a 8.5 sec. 1/4 mile at 132 mph. It's in a 20' stoker tunnel.He runs a rodeck with nitrous. VERY FAST out of the hole.They haven't had any problems with the drive.

[DogHouse]

HD, I think the reason that most tunnels cavitate out of the hole is more a function of drive mounting depth and the typically highly pitched props rather than the hull design. My Cheetah tunnel hooked up great out of the hole and pulled skiers like crazy, but the prop shaft was 8"-9" below the keel so the 26" pitch prop was getting good clean water. That's also why it only ran low 90s with over 750 hp on tap. With the Blackhawk the propshaft is really high and the ones that I've seen run really throw a lot of water, even at low speed, not good for short line skiers! The rooster tail may be an even more important consideration for skiing than the poor holeshot performance.
-brian

[MACH26]

Rocket-J,
I used to own a 22 daytona w/ a 502EFI and a Blackhawk. I must say the drives are way fast on the top end, but I eventually through in the towel and went with a Bravo. The problem w/ a surfacing drive is the 502EFI didn't have enough power to turn the 29' props when they are submerged, but once your on a plane the thing screamed (94mph w/ a stock 502). The solution seemed simple, ADD POWER. Well that made the drive very vulnerable to breakage, and being that the drive and all the parts are discontinued, the only solution for me was to loose 7mph, have a great holeshot, and a non-obsolete drive. Hope this helps...
formerlyMACH26

[HavasuDreamin']

Mach 26 has a good point, you break something in that drive and what do you do? That would be foremost on my mind. Good Luck!

[Rocket-J]

Thanks guys. You have answered my question and I am going to pass on this boat. Al

[RiverDave2]

Rocket J, Alot of Cats aerate (not cavitate) out of the hole becuase there X dimensions are way high going for every last mph. There is a benefit to it though, becuase of the "aeration" this allows them to run a really high pitch prop for top end #'s.
Some V-Bottoms do have this problem as well. I have a friend with a Brand New 230 Eagle Eliminator and his aerates bad coming on plane. He's tried different props etc.. and Nothing seems to help. However his boat is a few mph faster then the other ones he's raced.
Scarab made a boat called the P-29 which was basically a "race version" of there 29' boat. The boats were pretty much the same throughout, although I heard somewhere that the P-29 was a little lighter. The main difference (that I could tell) was the P-29 had BlackHawks on it. The owner told me that it was a little "sensitive" getting it on plane, but the boat ran about 10mph faster with 2 blackhawks then two bravo1's. (according to him, but I believe it)
RD