Blackhawks.........

[Rootsy]

on an 18 barrelback... i know Mr Allard was going to try it but i don't believe he ever did... since i have a clean slate to begin with and i am going to do a few bottom modifications this might be a viable option for me... Do as Waleye and Tom did and move the motor up for the proper X dim... i for SURE am putting a bravo transom assy on it anyway.. so what the heck... BUT unlike the X18 i have a sharp V keel and i can make the strakes any length i want...

so give me your opinions, thoughts, concerns... hopefully i can get the boat moved to the new shop after the holidays and get the glass work finished and get her painted before the snow melts... I am probably going to use the motor from the 16 with a few changes... what direction it's going to go other than a freshening i am not exactly sure...... if you get apples to apples with the X18 i and my motor i should easily be able to pull 31's...

just some thoughts.. it's winter.. i'm blueprinting http://www.donzi.net/forums/images/smilies/outtahere.gif

[Woodsy]

Jamie....

Waleye runs a BH with 1.65 gears... you will probably need to run 1.5 gears with the HP your motor is making.

Just mount the BH so that the bottom of the torpedo is even with the keel of the boat... you will be fine!


Woodsy

[DonCig]

Jamie, the .pdf spreadsheet in this thread should help you. If you have the BH drive, I would definately do the project. If you have a bravo drive then I would put it on and try and produce some more HP in the engine compartment.
Don


http://www.donzi.net/forums/showthread.php?t=42328&page=4

[RedDog]

If you raise the "X" and use the Bravo - wouldn't that give similar results to running a standard Bravo "X" with an IMCO Shorty? Bravo or Blackhawk - either way raising the X seems like a plan

[Rootsy]

Don,

No i don't have a blackhawk yet... i have a bare split hull with a blank transom and stringers... i can do whatever i want to her for a transom assy hole and placement... my 350 makes 410ish corrected HP N/A... this could very well increase... or it might decrease... if i don't have to go radical i won't... as much as i love high HP screaming mouse motors i want manners in this boat... and i want it to be capable of running with the faster group of boats if so needed... very well might end up with an injected supercharger setup if the price is right...

we know, from experience, that an 18 hull, with the bullet placed at the keel as woodsy said, with a (as far as i know, stock) 350 mag MPI motor will run 77ish mph... and from what i have witnessed it runs flat and stable... but maybe i am wrong... i am sure woodsy and such will enlighten me...

my only concern, how is the mid range performance... it's fine and dandy to be able to run full tilt but i do like to cruise too.. especially on long runs. This is a concern with me... out of the hole i don't particularly care bout.. i am not drag racing or pulling skiiers.... but performance from 2500 - 5500 rpm i do care about...

[Woodsy]

Root...

Walleyes boat is rock stable, the mid range punch is good as well. He rigged the boat with a seastar internal hydraulic setup, and its pretty darn stable. The only thing I would do to Walleyes boat is add a set of tabs for rough Winni days...

Ping me an e-mail... You need to talk to T-Bone (Tom Davis) on what he did to reinforce the stringers etc.


Woodsy

[MOP]

Jamie you need to get hold of Steve to get a measurement with the drive trimmed level with the bottom, I looked his over pretty good at 1K his drive bullet is well above the keel trimmed level, my BH on the 22 was 3/8" above the bottom trimmed level. Check the picks in the posts below it will give you a rough idea of how high it needs to be, both are full down in the pics.

http://www.donzi.net/forums/showthread.php?t=38407 Post #8 is Steves drive
http://www.donzi.net/forums/showthread.php?t=39993 Pic of my drive

Phil

[Rootsy]

woodsy you have mail....

MOP,

the bottom of the torpedo at the prop appears to be even with the keel on stevie's boat

[Lenny]

If you raise the "X" and use the Bravo - wouldn't that give similar results to running a standard Bravo "X" with an IMCO Shorty? Bravo or Blackhawk - either way raising the X seems like a plan

Nope. The Blackhawk is 8" :eek: shorter than a Bravo to prop centerline to start with. Then, it is suggested to mount it UP an additional 3" over STOCK X-dim placement on the 18 which is about 14 1/2" on the 12-13 degree transom. That puts the propshaft centerline UP from stock Bravo placement 11" :eek: So, a stock position transom placed Bravo with a 3" shorty would still be 8" lower (drag) than a properly placed BH. The 3" shorty on a stock Bravo placement gives you what you would get by bolting on an Alpha SS.

Jamie, I bought the Blackhawk CD (Real Mercury Service manual) Once I burn it to my 'puter, you can have it to play with :)

[Rootsy]

or just make me a copy lenny?

len, did you ever get my email reply to you from a few weeks ago?

[Lenny]

Yep Jamie, I did. It is running around in my MIND still.

[Mr X]

Lenny,
could you please burn me a copy of the CD also?

Thanks
Ted

[Lenny]

Ted, uh huh :yes: It should be here in about 5 days. I will make ten if they are not encryted like some of the $uckin music CD's I have bought recently. :mad:

email me your full addy, zip, planet etc to highlnd@telus.net

[Rootsy]

would this be ample power for the 18 and a BH combo??? :eek!:

heck i think it might even fit under the hatch... :)

http://www.magnacharger.com/images/highres/Gen1E%20Small%20Block%20Chevy/Gen1E%20Photo%201.jpg

[mrfixxall]

rootsy,,,,no offence.....looks like a all show and no go motor.....engine stand is the same color as the block and ware are the head bolts and the super charger pully???:)

[Rootsy]

Crap, i thought i forgot a few parts during assembly... thanks for reassuring me that i'm not going out of my mind...:banghead: :banghead: :banghead:

[mattyboy]

Rootsy,
do we know what X Pearson or CDMA run their 18's at??
how much deeper is your keel a foot or so from a round keel 18??
looking thru all my pics the only other sharp keel full length inner strake boat I have seen is the magnum 27, but that's only in 90 gig of photos I have,
will you have tabs/planes on this one??

[MOP]

Jamie did you pickup one of the plastic mock up blocks?
I have been reading about the full strakes, I think you may have to shorten them to get rid of the stern lift if you do decide to run the BH

Phil

[DonCig]

Jamie, I am not sure what engine H.P. you are considering putting in your boat but this sheet may help you with your gearing in the Blackhawk. I would spin as high a pitch prop as makes sense. I should be spinning the 31" at 1:65R around 5,500 rpm at sea level and the 27" at 1:65R at 6,000' elevation here in Colorado. Lake Powell is around 3,700' in elevation, so the 29"'s should be just right.

[Rootsy]

honestly i don't quite know what HP is going to be going through it... YET... 5500 rpm is the ceiling for rotational speed AFAIC. Whether it is N/A or supercharged depends on how my contacts come through for me :biggrin.: If i keep the 350 in the 16 i'll probably decrease cylinder head size and what not so it'll probably be down in the Scorpion power range, etc... then again i am gonna freshen it either way so i might just toss in a 383 crank and a set of pistons... if the bores are round and square anyway... we'll figure it out.. i have a lot of glass work to do yet.. :bonk: