100% newbie

[Thefner]

By the way you described it, it does sound similar. I know wide open there is only about 6 inches of the hull in the water. It only does that trimmed up though. When you trailer it up past full up it starts getting pretty unstable. It makes it throw up a heck of a rooster tail though. I'll try to get a video of it running next year. It's too cold for my preference to take it out any more this year. I do have a picture of it running somewhere. I'll try to get my hands on it. I think it may be mixed in with my mom's old pictures at her house.

[ Post made via Android ]

[aaron78viper]

I know this is an older post already, but im noticing the low water pickup on the gearcase. What is the point on that outdrive? Did hydrostream install their outdrives high enough to need that? Is it possible at all to raise the propshaft height in that boat? Seems like it would dig the hull into the water if you trimmed that up at speed.

[Thefner]

Hey Aaron,
I honestly don't know the answers to your questions. I'm still very new to the hydrostream fan base. What I do know is that being trimmed up doesn't drive the hull down. In the pictures I took the trim is on the trailer setting, so that may be why it looks that way to you. When I'm driving it the higher I trim it the more it feels like the boat is about to fly on me until eventually the prop will break the surface of the water. One other bit of information I know is that this out drive is one that was used by mercury racing on their boats in the 90's. It's some upgraded version of the alpha. I only know this because about 6 years ago, when my dad owned it, one of the driveshafts in the drive snapped and we couldn't find any replacement because they were never mass produced. We had to have one custom made by some guy in Pennsylvania. From what I've gathered this boat is kind of an anomaly because there weren't many made and the information on them is incredibly scarce. There are tons of other guys in here who may have much more information on your questions, at least I hope so because I'm curious as well. Thanks for the reply!

[idvette]

I think what Aaron is getting at is that the outdrive is fixed to the transom, and as with most outdrive installs, is low enough below the hull to not necessitate a low water pickup. By trimming up (and producing a rooster tail) what you're doing is essentially lifting the bow by driving the back of the boat further down into the water. Ideally what you want is neutral trim and low rooster tail. That way the prop is driving the boat forward efficiently, not wasting energy carrying the bow or being too deep and forcing the back few feet of the hull into the water. Wish I could draw a picture to explain it better. Anyways, with an inboard/outdrive setup, the outdrive typically isn't high enough to run as efficiently as an outboard. It's well under the planing surface of the hull (the pad on a 'stream) and therefore creates efficiency issues, affecting speed and handling characteristics. If the outdrive was adjustable in height (which I doubt, but is the core of Aaron's question) you could raise your prop shaft height and make the setup more efficient, enabling higher speeds. As you go higher with your drive, you need to worry about where your motor is getting it's cooling water from, hence the "low water pickup", which is an aftermarket (usually) modification to get cooling water from a lower point within the gear case. Hope this helps your understanding a bit more!!

[ Post made via iPhone ]

[aaron78viper]

^exactly. I think you could probably bolt on a normal gearcase to that outdrive and not hurt anything. and you could find parts. Ive worked on a few of those outdrives doing gimbal bearings and water pumps, and they look exactly the same with the exception of that gearcase.. which I would not expect to see on an I/o that is buried to the cav plate and a stock 270hp mercruiser chevy. I would look into that. might not need that fancy gearcase on that boat

[HST4ME]

That's really cool, That engine/drive package is pretty rare, an original Alpha SS is tough to come by. Very cool package. The SS is a little over 2 inches shorter than a stock Alpha, and the couple I/O streams I've seen had the x dimension set up pretty high. I wouldn't change a thing.