Jet Conversion to Surface Drive???

[Devilman]

There was a 21' Eliminator with an Arneson Surface Drive on E-Bay about a year ago. Claimed to be the owner of Arneson's old boat, very clean and looked awsome.
Speaking of which......:jawdrop:
http://www.***boat.com/image_center/...0/arneson3.jpg
http://www.***boat.com/image_center/...0/arneson1.jpg
http://www.***boat.com/image_center/...0/arneson2.jpg
And here is the listing description:
Description
Item Specifics - Power & Fishing Boats
Type: Jet Use: Fresh Water
Make: Youngblood Engine Type: Big Block
Model: Youngblood Engine Make: Chevrolet 498
Year: 1979 Engine Model: Chevy 498
Length (Feet): 21.0 Primary Fuel Type: Gas
Beam (Feet): -- Fuel Capacity (Gallons): 11-20
Hull Material: Fiberglass Hull Identification Number: --
Trailer: Included
Vehicle Description
If you like really fast toys, then check out this Youngblood Pickle Fork/ Tunnel Hull speed boat. This is a 1979 boat that has been really cared for. It is very unique. The engine is a very potent 498inch Big Block Chevy engine. It also has a Arneson surface drive. The original owner spent A LOT of money perfecting this combination. The hull was redesigned by Mr. Arneson himself. The hull was then modified to his specifications. It will handle speeds of over 120 mph and still be very smooth and stable.
The current powerplant is a new engine that has 10.5 :1 compression. It has a radical hydraulic roller cam. The heads are oval port closed chambers (original 427). It sounds awesome! This engine produces about 700 hp without nitrous and with super unleaded gas! It has a billet MSD distributor, MSD ignition box, Holley electric fuel pump, and a hi torque mini starter. It has power steering, and a new external water pump. The carbs are 750 double pumpers that work perfect. I have personally been 85 + mph with this combination. (The speed was still climbing after the speedometer quit working after 85). I have driven super gas door cars, 7 second dragsters, and very fast street cars, but there is nothing like a really fast boat. The sensation of speed on the water is incredible and hard to describe.
This boat also has a "shorty" Powerglide transmission. It is built with all good parts including a billet aluminum shorty tail housing. Not only does it give you 2 gears for incredible acceleration, it also is a dream when it comes to idling around the boat dock and loading is a breeze.
The Gel Coat on this boat is original! It is not a repaint that will chip away with use. Wax it up now and then, and it will last for years to come. Look at the reflections in the pictures! It has never been crashed or sunk. The engine was mounted with front and rear engine plates just like a dragster.
The Surface Drive unit is very expensive and practically indestructible. The propeller is stainless steel and in great shape. These units are used a lot in offshore racing applications. Don’t be afraid to put a really powerful engine in this boat! It used to have a twin turbo setup and went 118 mph with that combination. Talk about a fast lake boat!
The trailer was custom made for this boat. It has surge brakes, buddy bearings, new tires and wheels, and is very easy to load.
Although this boat looks like brand new in the pictures, it is not perfect. It shows extremely well and gets major attention on the lake or on the trailer. When you pull up to the boat ramp with this thing, you will gather a crowd in no time. The boat looks awesome, and everyone freaks out on the Arneson drive.

[Unchained]

It's a real interesting setup but I would have to speculate that the out of the hole takeoff performance would not be good because that surfacing prop is going to cavitate like mad until you got some speed up. That large of a prop is going to have a huge torque reaction on the hull and they have used a large rudder to try to help with that problem. That's why v drives use such a small prop diameter, to minimize the torque reaction and it's still a lot with a little 11" prop like I use.
Once it got up on plane I would think it would be an efficient running boat.
The shaft is coming out parallel to the keel so if you trim it you are going to change the elevation of the prop more than you are going to change the thrust angle.

[Pops@Aggressor]

My Brother Ron Jones ran 2 Arnison Surface Drives on a Rudy Raymos/ Ron Jones 44 footer twin Chevs un-blown, Head, Galley, Sleeping/setting area, 86 MPH. He made some change spanking some much Bigger label Hulls off Catalina with that Hull, in the late 70, early 80s. Later on both Rudy & my brother tried to get the molds to produce, which went to Costa Mesa then to an Aussie's or New Zealand were never again found. Surface with choppers worked but are scarry.

[Havasu Hangin']

It's a real interesting setup but I would have to speculate that the out of the hole takeoff performance would not be good because that surfacing prop is going to cavitate like mad until you got some speed up.
With the prop being set so far back, I don't think they'd cavitate getting on plane since they are so deep until the boat takes a set (most of the boats I've been in actually bog the motors until the boat takes a set). Torquing while rolling over would probably depend on the size of the motor?
Once up on plane, with the hydraulic steering and half of that (big) prop out of the water, I'd imagine it helps with the torque steer.

[airboater67]

Here's one for ya!

[Devilman]

Cool.....
http://www.***boat.com/forums/attach...3&d=1190872297
http://www.***boat.com/forums/attach...4&d=1190872315

[rustnrot]

airboater67, is that your boat? Some of you may not know, but that is a Pulse Drive surface drive designed by Harry Schoell www.pulsedrive.net
That is a very nice installation, but just for the record the Pulse Drive is not marketed specifically as a "jet drive replacement" surface drive. It can virtually replace any drive but is not a "bolt in" affair.
We are doing a conversion from jet to Pulse Drive on a Chris Craft XK18 jet boat. airboater76 or whoever owns that boat please contact me!

[Unchained]

That pulse drive looks pretty simple. Like someone could have their engine and a trans mounted in the boat with the tailshaft of the trans right at the transom and have a single U joint just outside the hull next to the transom that would allow for some trim. I've seen long driveshaft yokes that could go through a seal at the transom and still plug into the trans. The driveshaft wouldn't be dragging in the water so a large shaft diameter would not be a problem.
Some energetic soul could retrofit a tunnel boat and really have something different. Looks like all the steering is done with the rudder(s). I question the low speed manuverability because the prop wash would not be blowing against the rudder. There certainly would not be any steering in reverse, same as a V drive. It would take a mighty strong support to have the rudder that far off the transom.
Maybe having a steering cylinder instead of a rudder would make more sense.
I guess water skiing would be out of the question.

[Squirtcha?]

I question the low speed manuverability because the prop wash would not be blowing against the rudder. There certainly would not be any steering in reverse, same as a V drive.
Actually Mark, there's a video clip on the webpage of a boat running in reverse (amongst other things). It's faster and more manuverable than my jet by the look of it.
Although pretty cool......and probably more efficient, it sorta goes against all the reasons I have a jetdrive.
Running the river in pretty shallow water earlier this summer I had a mishap (link with some photos below). The jetdrive/intake suffered some damage, however if I'da been running one of these surface drives (or any kind of prop) it would've completely demolished it. Mind you I still had some repairs (damage control) to perform (fiberglass repairs), but I didn't buy any parts and I was on the water two weekends later.
http://www.***boat.com/forums/showth...=rough+weekend
Oh yeah............and there's a huge ass'd prop just under the boat!
I'd still be curious to hear some numbers (before n after conversion from jetdrive using the same power)

[Unchained]

It looks like a project I would like to do.
Now if I had money falling out of my a** and were to start with another 21' Daytona or Liberator that was previously an outboard powered boat that would be a good prospect. The OB hull would have a real heavy built transom to attach the hyd cylinders to. I think I would not use a rudder like the Pulse drive unit and go with hyd steering. I'd probably use a 427+- ci aluminum small block with a TH400. TT / EFI of course.
I would think the surface drive would have great river bottom clearance.
From the pic it doesn't look to hang any more than a couple inches below the keel and you could probably trim it all the way up if you knew you were going to have a bottom clearance problem. That prop looks like it would be a major investment. Without OD gears to change like a V drive your only fine tuning would be in the prop. It may take a whole raft of props to get it right.
Maybe I shouldn't be talking up other drive ideas on this forum. :idea: