diy surface drive?

[moTthediesel]

Thinking about a surface drive for a very small (1600cc) inboard hydro.
Anybody ever seen a home brewed unit?
Was it successful?

[moTthediesel]

Nothing?
I'm looking at some old plans for a Charles Mower designed one step hydro from 1927. Very much like a small "Baby Bootlegger", if you know that boat.
Plans as shown feature a forward rudder (yikes!) and a long conventional shaft drive to the wheel. I just can't see the sense in dragging 6' of exposed shaft through the water, especially in a boat that needs to go fast with a small engine. And the forward rudder? Makes me think about how much fun it would be to drive a forklift @ 50 mph.
I'm thinking of a non-steering surface drive with conventional rear rudder, something more like a "Simpliciy" style unit rather than an Arneson type.
I have lots of good reference materials for engineering standard props, but I don't know where to look for sizing/pitching/cupping surface drive props.
Can anybody here point me to some good info?
moT

[lucas12]

Go to 'Building a 21' cruiser' in projects proposals.
I have one drawn up can email the dxf's soon
Simon.:D

[xrudi]

Hello

We produce suface drives for engines between 20 and 70 hp. This might be something for you. Please viste our webpage www.levidrives.com and view our model LD 170-150.

Best Regards

Rudi

[ted655]

There is a builder here that makes his own.. They are fairly simple, but functional. Not sleek or sporty looking. He charges $1500+. Off the shelf components
Ted, Henderson, LA.

[Frosty]

This subject has been thouroughly discussed in the thread "shafts thru the transom'. I think you will find a lot of answers there.

[buckknekkid]

Ted do you have contact information?

[ted655]

I can try to get some info for you, if interested. OR pictures of one of the boats, next time I see one.
Just this month, he is wrapping up his projects and was semi-retireing.
Another type of propulsion they use here in the swamp is a BIG improvment over the straight shaft Go Devils. They are "Pro Drives", made here in lorieville, LA..
A great "outboard" type of surface drive motor. I have gone for test rides with these and they are impressive. A flat bottom boat will "scoot" in 1" of water!
http://www.prodriveoutboards.com/home.htm

[Mudder]

Here is another. We build our own 45 horse engines. www.mudbuddy.com

[Misogynist]

Here is another. We build our own 45 horse engines. www.mudbuddy.com

Does it make enough HP to haul all the wives at once?..... lol... sorry,, couldn't resist that one....... :p

[RANCHI OTTO]

From my data base:

I give to you the names of manufacturers or models:

Arneson
DBD Marine
Flexidrive
Jolly drive
Levi Marine
Trimax
SDS
Q-SPD
Sea Fury
Saro Drive
Pulse drive
Sea Rex
Top System
etc.

Here you can see The ARNESON installed on my MANTA ASD design (2 x 1150 hp / +50 knots)

[FAST FRED]

For decades the folks in Asia have been mounting a car engine , and a shaft on the stern of FAST small boats.

The prop is immersed fully as the boat is started and slowly lifted to surface drive as speed increases. The unit also pivots to steer the boat .A simple tiller controlls it all.

Should be really EZ to do with your engine , a heck of a lot fewer parts, and nothing in the water at rest.

Perhaps one of our fine members in Indonesia or ? could add a photo.

FF

[Quicksilver]

For decades the folks in Asia have been mounting a car engine , and a shaft on the stern of FAST small boats.

The prop is immersed fully as the boat is started and slowly lifted to surface drive as speed increases. The unit also pivots to steer the boat .A simple tiller controlls it all.

Should be really EZ to do with your engine , a heck of a lot fewer parts, and nothing in the water at rest.

Perhaps one of our fine members in Indonesia or ? could add a photo.

FF

Sounds like the levidrive, which has already chimed in on the thread, or is the one your talking about a diy.

[TerryKing]

http://boatdesign.net/forums/showthread.php?t=1681 post #87 has a photo.

[tom kane]

From my data base:

I give to you the names of manufacturers or models:

Arneson
DBD Marine
Flexidrive
Jolly drive
Levi Marine
Trimax
SDS
Q-SPD
Sea Fury
Saro Drive
Pulse drive
Sea Rex
Top System
etc.

Here you can see The ARNESON installed on my MANTA ASD design (2 x 1150 hp / +50 knots)

I think you forgot to mention CAM.PROPULSION PIVOTAL DRIVE..Probably the first ever.. in this line of beasts.

[boatguy64]

My friend was a guy named Scott Schoell. He was Harry's nephew. We built our own drive and was very sucsessful. Did you work it out or are you still looking? It is not as hard as it may seem.

[TerryKing]

We built our own drive and was very successful. Did you work it out or are you still looking? It is not as hard as it may seem.

I'm very interested in building a DIY drive. I have some mechanical design / machining / welding background. Can you point to any info/photos of what you did??

Thanks!

[boatguy64]

I don't have photos. But I can build it. The design is in my head, you know. I might could explain it

[Frosty]

Thers nothing technical about a surface drive . It is simply mounting the propellor on the surface.

The problems come with just that--holding it there.

There lots of manufactures out there claiming theres is best.

Its the boat-engine- gearbox- and prop that does it.

Some steer by rudders and some steer by moving the whole drive. It would appear therefore that any configeration can work if applied correctly.

I myself have also made a surface drive system and mounted this system on a brand new boat, (at considerable financial risk).

Im happy to say that they were succesfull and I can exeed the speed of the boat manufactures speed with slightly less HP.

However reversing has been a difficult problem to solve.

From not being able to reverse at all. to a reasonable reversing performance that I feel now is acceptable.

If I did this again reversing would be the first consideration.

Some one said to me "what do you bother about going backwards for"

Have you ever tried going into a marina on a breezy day with less than good reversing power,-- not recomended.

[boatguy64]

The issue regarding reverse is a serious consideration. It is possible to overcome. It depends on the hull design. We built the hull with a suface drive in mind from the begining. I will post some pics when I can.

[tom kane]

If you have a trimmable drive that drops down to 20 degree shaft angle,which is what an average fixed inboard drive is there should be no more problems reversing with a surface drive, than a conventional inboard drive.

[Frosty]

If you have a trimmable drive that drops down to 20 degree shaft angle,which is what an average fixed inboard drive is there should be no more problems reversing with a surface drive, than a conventional inboard drive.

Building in 20 degrees down is quite a bit of extra hydraulics and im still not convinced it will cure the problem. It would need to be a long shaft of the Arneson flavour.

I am not in favour of external hydralics on larger sea going vessels that live in marinas and or only get hauled out anually. Variable trim systems for these boats is almost impossible to maintain.

As Boatguy said it really does need very carefull consideration of the transom shape. As the prop is so high and on some boats of shallow draft the tips of the blades can be on the surface at rest. If you have a flat 0 degree transom the water from the top of the disc and some of the water from the lower part of the disc can accumulate to the extent of having as much thrust bouncing off the transom as there is whats left of forward thrust. Hence the boat doesnt move --infact can still move forward as the thrust bounces off the transom into forward thrust.

I recently designed some "reversing plates" to act as a dummy transom, but also tried to multipy available thrust by shaping the plates in a way to gather and concentrate all possible thrust under or to the side of the vessel's transom.

These were succesfull, but as being made in stainless steel they encouraged quite a bit of electrolisis. I have just replaced them with a fibre glass version.

[Willallison]

As Frosty suggests, it's not the angle of the thrust that's the problem - outboards and sterndrives run at essentially zero angle, and the back quite ok - it's the transom reversing or at least neutralising the thrust. My understanding is that a transom angle of around 45 degrees can overcome it - at least to the point where reversing is acceptable

[boatguy64]

Harry Schoell's PSI drive or Pulse drive is an excelent solution to a lot of the problems discused here.

[mydauphin]

Hi guys,

I have my boat ready to go with custom home made Surface drives. My problem is I need something like thrust bearing on the aquadrive. I cant find anything reasonably priced. Aquadrive and Python Drive are very expensive. Found thrust bearings but no housing to put them in. I would have to machine something. Anyway, I see a lot of money going out the door. Anyone found a way around this. thanks

[tom kane]

Have a look at SKF "FY" Bearing housings.I have used these in trimmable S/Drives.They can be used as self aligning or variable shaft angles for trimmable drives.

[tom kane]

There are many ways to set up a fixed or trimmable S/P drive shaft.Image shows a 1960`s trimmable drive used for 30 years,with the choice of running in S/P or subsurface drive.Patent was granted 1973 NZ patent no 169862.The drive can be trimmed from the helm using cable,linkages,or hydraulics.Prop shaft is in a torque tube with water lube brgs at the prop and half way up at water level.The drive can run down to 20 degree shaft angle or lifted to adjust running depth.Because the prop is at an angle the decending blades have a greater pitch angle and hold the prop shaft down while running.The water gland does not leak because it would usually be above water level unlike glands fitted at the keelson.While running shaft torsion effect lubes and cools the water gland.Motor is usually at 10 degrees angle and twin u/v`s with sliding spline give 10 degrees up and down movement using SKF "YF" series housing and thrust brg.Motor,thrust brg,all of the drive is soft rubber mounted and runs super smooth.

[mydauphin]

The boat lwl 60 feet, 15 foot beam, 3 foot draft, weight 40klb Aluminum Planing hull, Twin DD 671 450 hp, 2-3/4 shafts, tranny 2 to1, lots of torque.

Those SKF bearings are too small, I am looking at a back to back set of 29413 E in a custom housing so far.

The whole setup is similar to power-vent with rudders inboard of props. The drive would be fixed at about 5 degrees. Shafts within tubes. Props would be about 5 feet out of transom. Transom is at 45 degrees and was originally setup for Arnesons. They are similar in size to a ASD10


The rudders are fixed with the rudders separating the prop wash so that reverse and slow speed will handle similar to non-surface drives. I have even considered one big rudder, but I would get zero prop effect on rudder and would make handling more difficult.

I have most of the parts except bearings ready to go - I am not happy having to custom make bearing housing so I am still looking for a better solution.

Many have suggested straight shaft but I am sure of after the fact adjustment to shaft angle to achieve maximum results

I am looking for simplicity, lowest cost, and performance.

I'll post some drawing when I finish them.

[tom kane]

The bearings suggested are available in 2 inch shaft and bigger and are used in big hydroplanes doing 180+ MPH.The same set up is used in heavy earth moving and leveling equipment.

[mydauphin]

The bearings suggested are available in 2 inch shaft and bigger and are used in big hydroplanes doing 180+ MPH.The same set up is used in heavy earth moving and leveling equipment.

I am having trouble finding it on 2 3/4 shaft size. Do you know a part# ?
Much Thanks

tony

[tom kane]

There is a big range many style and purposes.Look for series Y bearing flange units cast housing square housing grub screw locking self aligning.FYM is 2.15/16.inch.there should be 4 inch shaft and above.
www.skf.com/skf/productcatalogue/jsp/search/

[TerryKing]

There is a big range many style and purposes.Look for series Y bearing flange units cast housing square housing grub screw locking self aligning.FYM is 2.15/16.inch.there should be 4 inch shaft and above.
www.skf.com/skf/productcatalogue/jsp/search/

Tom, are these primarily thrust bearings, like 'flat tapered rollers', or do they have side-load capability too, like a set of two tapered rollers?

In your designs, have you used a shaft collar of some type to present the thrust load to the bearing, or does the shaft have a shoulder?

...just thinking of how I'm going to DIY this stuff in China next year...

I used some SKF flange-type bearings in big rotary mowers I built years ago.. I'll get that catalog.

[tom kane]

SKF "Y" series, FY model.Shows housing with thrust brg fitted and angled.It revolves to any 360 degree position.Brearing slides out through two slots for renewl.Collet fits on shaft with locking grub screw and is designed to lock onto brg and shaft by of set of-centre turnings shown.This will give shaft angles up to 20 degrees and even steering left and right,up and down if so designed.If you want more shaft angle a different design and pivot point is required.Similar to part of the drive in an inboard/outboard.The design shown is probably the simples you can build.

[tom kane]

Image shows how standard conventional twin universal`s with a sliding spline can give 20 degrees of movement and run in any direction.Usually this set up is only used in a fixed position since Adam..10 degrees motor angle,10 degrees taken up by u/v`s.Electric motor is running and maximum angle can be obvious when angle is too great.Support bearings on prop shaft should comply to 20 40 rule.No closer than 20 times shaft diameter,no further apart than 40 times shaft diameter.

[tom kane]

Auto parts for a surface drive? If you want a real heavy drive pinch a front wheel drive unit from a heavy industrial tractor.It would be adjustable up and down and give stearing.

[TerryKing]

Tom, thanks for the practical info and getting it up for us here.. Please keep on with it!

[Frosty]

Auto parts for a surface drive? If you want a real heavy drive pinch a front wheel drive unit from a heavy industrial tractor.It would be adjustable up and down and give stearing.

If they are constant velocity joints they wont take thrust. I know they use CV on marine installations but they go through a thrust block first.

[TerryKing]

If they are constant velocity joints they wont take thrust. I know they use CV on marine installations but they go through a thrust block first.

Frosty, if the wheel spindle is kept in the package, it has tapered roller bearings that take the side-thrust when cornering the vehicle, which can be considerable. So running a boat underway would be like a constant right (or left) turn with that thrust block.

That said, I'd rather just couple the drive axle after the first (inner) CV joint on a front-wheel drive vehicle to a good thrust bearing like the SKF "Y" series, FY model that Tom showed earlier.

With the differential locked up like for off-road vehicles, there would be a 2 or 3 to 1 reduction ratio (depending on overdrive) on an off-the-scrap-lot front wheel drive engine-transaxle assembly. Running the right prop on a displacement craft should be pretty easy.

Running two identical engines/transaxles facing opposite, you'd have counter-rotating prop shafts at low cost. No marine transmission. Negative: Reverse is a poor low ratio. But I ran a modified car transmission on a small inboard years ago and I just revved the engine to 3000 or so and there was enough reverse for anything reasonable...

What I wonder about is how the numbers would come out for two 100 hp @ 2800RPM (derated from 160 hp * 4800RPM) V6 car engines on a 25 to 30 foot planing hull and the 'right' surface-drive props for the 2.5 or so reduction ratio.

The DIY Budget version: Just added raw water pump(s) and heat exchanger, Dry exhaust.

Hmmm...

[Frosty]

A trimable steerable surface drive is a problem . Its easier to make DIY fixed shaft. This will also be more robust and maintenance free.

Arnesons look great and are the biusness for tearing across the bay before taking it out and washing it. If its going to stay in the water you dont want hydraulic rams in there.

[TerryKing]

A trimmable steerable surface drive is a problem .

With twin engines, I'd be inclined to not make a DIY drive steerable, just trimmable. That might be purely mechanical, not adjustable underway, or use a mechanism where the hydraulics/servos were protected inboard.

With rudders and reversible drive the steering and low-speed maneuvering should be OK. Have you seen configurations like that? What do you think?

[Frosty]

Trimable ,steerable,--youve already done the work all you need is an extra ram.

With steerable and trimable youve got the joint to worry about and keeping sea water out. A rubber grommet or boot is all you can do and antifouling will be a nightmare.

The picture attached is a cat that I own to this day and I made these drives 4 years ago. the reversing deflector is on the floor and without them it reverses awfull. The rudders are number 3 and are final.

The boat performs slightly better than manufactures with 100HP less.

[mydauphin]

Frosty, I dont understand reversing plate. Does that go in front or behind prop. Looks like Levi Drive. Did you make semi-circle out of aluminum or steel?

[Frosty]

The "reverse plate" simulates a 45degree transom. As you can see from the picture the transom is flat ,any thrust from the reversing prop hits this and it goes out the the side or bounces off. Without the plates reversing is very poor.

Those on the floor had just been made and replaced some stainless steel ones that were giving me electrolisis problems. They are simply attached and does nothing but deflect thrust in reverse. When on the way they are out of the water.

Those are rudders number 3 and are satisfactory. They were bent in a press. The flare at the top is a steam pipe 6 inch to 3 inch reducer machined down.

It is very difficult to build in strength into tunnel rudders when the rudder shaft does not continue down through the blade.

I personally know sony Levi and talked to him in great lengths before making this system. So I guess similarity may be incidental, however the sony levy drive has a casing on which every thing is fitted to --mine is using the hull of the boat resulting in a lighter and more simple assembly.

[tom kane]

A rudder only when you need it.Dipping rudders,turn left,right rudder drops down into prop wash.Turn right left rudder drops down.No drag of rudders going ahead more speed.Drive is trimmable up and down 20 degrees.A shaped rudder gives more efficient and greater turning.And if you want to stop in a hurry,both rudders down.

[TerryKing]

A rudder only when you need it..snip..

Interesting, Tom! Is this a concept or is someone doing it??

WhatIf LEFT rudder comes down as left turn is wanted, same for right. So (maybe) if just a very small amount of course correction is needed, it's done mostly with the added drag of left rudder, until more side force is needed??

Maybe the rudder shape is such that at very slow speeds it has even more area rotated into the water... Maybe its outer profile is a half a spiral. So the full-down profile is like typical water-ski fins. Hmmm.

[tom kane]

I tried seperate leavers for each side,giving use of both left and right plus both down together.I tried cables to lift each rudder,using prop wash to pull them down.Hydraulic is slow,but geared up ok.I tried air like truck breaking which is better but difficult to tune, but the best option.The trick is to swing the rudders down to use all the prop wash effect.

[tom kane]

A drive using auto parts for 1600 cc. CV cover can be filled with silicon material (breast implant) for mechanical seal as well as CV cover.Water lube brg at prop end,gland seals before CV inside torque tube.Any water leaking past gland can be pumped from inside hull.Trim up down and steer.Motor at back of hull or over drive.Choice of gearbox or belt drive.

[Frosty]

No mention of a thrust block???

A CV (constant velocity joint) can not take thrust. You mention a ford 1600 ---so whats in the box --an outboard.

Sorry --dont understand.

[tom kane]

Impressed with the simple design concept of this old feasibility prototype?
DIY is using your ideas and engineering skills to to upgrade products to your requirements.If you think extra thrust is required and you have the recources and skills to make a good and useful product, and maybe come up with a new and novel and patentable idea the consumers would reward you and make you rich.

[Frosty]

Im sure we are all well aware of that Tom. I just asked why did you mention a 1600 and have some kind of outboard under a box. It looks a though the outboard just does the steering? But I dont understand it. AND you still cant use a cv for thrust.!!!!

[TerryKing]

...snip...some kind of outboard under a box.

After I looked closely at the photo, it seems there's a surface-drive unit with a boot going thru the lower transom, with (possibly) the casting/mount from an outboard HOLDING it. Tom, can you show us more of the whole idea??

[tom kane]

That was the cheap and simple way to try the idea,not cost much.The lower part of an old outboard for exhaust and steering, propstrut and even trim,very basic.
The motor in this case was inboard of the transom all soft rubber mounted using keelson for support and two short beams to take torque on frames.Four bolts on frames to secure unit which could lift out quickly.A motor in and over the transom inside the box was tried (Have photos).

The photo shown shows an early arneson drive which you could diy. There are water intrusion problems here getting into g/box.This would be an expensive development project.

[Frosty]

Ok now I understand but when the engine trims up the support bearing will need to slide down the shaft. There doesnt seem to be accomodation for that.

And what about side thrust( walk). Set ups like this need to be in twins with a mechanical tie bar as does most surface drives.

For a single installation you need something very strong like a levi drive capable of side and up thrust with a separate rudder system.

[tom kane]

The amount of useful trim up and down on such a short shaft is about half the diameter of the prop (10 inches) typical of the problem of short shaft S/P drives giving big prop angles.The usful turning angle is not much more than a rudder,30 degrees.There is room for inovative improvements on these designs.

[tom kane]

A long trimable shaft gives better shaft and prop angles and are easier to instal than fixed drives with fine fixed tolerances.A rudder steered from the back of a trim tab of a flat rudder will give better steering than just a flat plate rudder.Or use dipping rudders.

[TerryKing]

Tom, this is an interesting configuration.

Can you tell us a little more about the geometry used here?

How about the shaft / tube, aft bearing?

Where / how is the thrust handled?

What hull configuration is required?

All I want to know is Everything! ;)

[tom kane]

The thrust can be like that shown relating to SKF adjustable brg in earlier images and posts using two back to back U/Vs with sliding spline,or making a housing like front wheel drive auto to take thrust and trim. .You need a torque tube to support prop shaft using water lube brgs in lower half or use plastic style water lube brg material and fill torque tube with oil (water in there will not make plastic brg material fail).This also acts in place of glands.

The tail frame mounts prop strut and lifts up or down for trim.Aim for 20 degree shaft angle when drive is down as prop does little work lifted out of water more than 50% of prop diameter.

A hull with a flat bottom is where this drive gives advantages and just about any hull can be fitted with this drive.Take advantage of the flexable nature of the U/V`s and make the drive fully rubber mounted.

[TerryKing]

..snip..Aim for 20 degree shaft angle when drive is down as prop does little work lifted out of water more than 50% of prop diameter.
Thanks for the information..

Is 20 degrees what you meant? This seems very high angle??

[tom kane]

20 degree shaft angle down is about what a conventional inboard drive would be,you may not like running your drive in S/P mode so you can fit a conventional prop and run it in subsurface mode.S/P drive has disadvantages and lots of people are disapointed with it.Twin U/V joints are constant velocity joints.

[Grumpyrelick]

I am a newbie here but I couldn't help noticing that much of the scuttlebutt centred around existing drive units. You can build a DIY surface drive from scratch and I did it for under $2000. It was only moderately successful be cause I chose the wrong hull. (Hey it was free!) It is a 13 ft. Glasspar G3 with a 1985 Oldsmobile 3.8 V6 stuffed into it. (a poor choice for a motor but it was cheap) The prop shaft was cog belt driven (1.1:1). with a 6 degree shaft angle. The hull, with an outboard, required a lot of out trim to perform - something you don't get with a surface prop. Best run - about 40 MPH @ 3000. I expected over 60 @ 5000 RPM. I have more pictures of the machinery and can provide more info if required.

[IMP-ish]

I am a newbie here but I couldn't help noticing that much of the scuttlebutt centred around existing drive units. You can build a DIY surface drive from scratch and I did it for under $2000. It was only moderately successful be cause I chose the wrong hull. (Hey it was free!) It is a 13 ft. Glasspar G3 with a 1985 Oldsmobile 3.8 V6 stuffed into it. (a poor choice for a motor but it was cheap) The prop shaft was cog belt driven (1.1:1). with a 6 degree shaft angle. The hull, with an outboard, required a lot of out trim to perform - something you don't get with a surface prop. Best run - about 40 MPH @ 3000. I expected over 60 @ 5000 RPM. I have more pictures of the machinery and can provide more info if required.
Please post some more photos of your setup. I congratulate you on your ingenuity!

Have you tired a lower pitch or smaller prop to get your RPMs and speed up?
Your boat also looks kind of bow-down there. Can any weight be shifted aft as a test to see if you can get more out of the water?

[Grumpyrelick]

I suppose I should start at the beginning... This will take a few posts. I was given the boat by a neighbour who dragged it over with a tractor without the benefit of a trailer - in summer. Thankfully it was 1000 feet. Much earlier, I had been given the motor for a jet boat project. I made manifolds with a hand grinder & stick welder. The motor was bad so it cost me $700 for another and mains & rings. I added a cam from Pet Boy's. - probably 140HP. (these engines cannot take more than 5000 RPM. I shattered the jet drive (alignment problem) so I had a motor. I started with an article and DOS program for estimating the shaft line details from Paul Kamen. He has the stuff here: http://www.well.com/~pk/fishmeal.html. While I tried to get my brain around the theories and limitations of Paul's program, I went ahead with the build. The cogged belt I found would require a pre-load of about 1000 lbs. That is a lot of side thrust so I used a trailer hub for a thrust bearing. The tapered rollers would take the pre-load too. The belt and cogs came from T.B. Woods. Then came a plummer block and finally a stern tube with seal and cutlass bearing. You can see the care I took (not!) in jigging up the stern bearing. The final photo is of the drive running. Below the flexplate (no flywheel - these engines are internally balanced so you can get away without one) you can see the end of the trailer hub, then the belt. The cross member with the two bolts is for the support bearing (plummer block) then comes the water feed to the stern tube. I know I haven't answered all your questions by a long shot but I felt it necessary to give you some background. More later today...

[Grumpyrelick]

This picture, from a video shows the internals of my surface drive running.

[tom kane]

There is the option to have a Transom mounted Trim able jet drive to try to eliminate some of the water jet failings.Poor priming in shallow draught hulls,poor sea keeping in following seas. Better thrust at low RPM going slow.
Easy clearing of weeds and other rubbish.

Looks less threatening than an open prop.

[Grumpyrelick]

I did mention in my previous post that I tried the motor in a jet. Well it was a 14 ft runabout hull that came with a 35 HP OMC. I pulled the drive out of an 18 ft Dowty. Dowty built the Hamilton drive under license in about 1960. It the USA it was sold as a Buehler. These were an axial flow pump with 2 (some had 3) impellers. The Hamilton is an axial flow while Berkley, Jacuzzi etc. were mixed flow. I originally used a Wankel (Mazda 13B) but my neighbours ruined the motor so they gave me the V6. We got more out of the V6 than with the original 292 Ford because I ran one on the river :). I did replace the reverse gate with a nozzle and that made the real difference. 2 things bother me about jets. When you calculate the gross weight of the boat you have to add the weight of the water in the pump and that is significant. Also the designers limit the pressure generated and the volume of water pumped. Pumps cavitate when over-revd and you need lots of mass to push the boat Example: The Jacuzzi 12YJ will only go 55 MPH no matter how big the motor.
Besides using a jet would have defeated my original objective: to build a surface drive. I am now looking at a stern drive for the Glasspar because I love the boat. I have tried an airboat, outboard, V-drive, jet boat and now surface drive. Next will probably be a hydrofoil. IMP-sh had some questions so I will answer those tomorrow.

[tom kane]

Thank`s for the good all-round experience and photos you are passing on. I am not a fan for surface propulsion myself jets,tunnels,pods, pockets whatever you choose to call them I prefer to have the prop in dense water in the middle of the transom and the prop at least two inches below the bottom of the hull to make use of every rev you add to the motor and for good sea keeping qualities.
If you traverse shallow waters it is great to have the ability to lift your drive (not tilt it) and protect it from damage and still have thrust and steerage.

[Grumpyrelick]

I am sure you have heard about the fellow at a boat show who asked about the fuel economy of a 30 ft cruiser. Salesman's response: "If you worry about fuel economy, you can't afford one". Where I live (Ottawa river) There are no marinas near and all fuel has to be carried 400 ft through weeds and sharp clams because the environmentalists frown on 4 wheelers in the water. So fuel consumption is important to me but not for financial reasons. While jets are great in shallow water, they are nearly 20% less efficient than a stern drive because of the drag of the pick-up grate, the tube wall, the slip because of impeller clearance and the impeller hub and shaft in the water flow. A surface drive beats them all. The only things in the water are prop blades and rudder - even the hub is out of the water. Another observation: my 3 jets that I owned held a plane at 3500 RPM. My wife's 16 ft Hurricane with Suzuki 115 - 4 stroke requires only 2100 to maintain a plane. I also had a 430 HP V-drive that would plane at 1800 RPM. I am not badmouthing jets - I had 3. I am still considering one for the Glasspar as my second choice.

[Grumpyrelick]

Please post some more photos of your setup. I congratulate you on your ingenuity!

Have you tried a lower pitch or smaller prop to get your RPMs and speed up?
Your boat also looks kind of bow-down there. Can any weight be shifted aft as a test to see if you can get more out of the water?

This hull was very advanced in 1958. While other boats had round chines and flat bottoms, the Glasspar had 12 degreed of deadrise. It was the forerunner to the modern deep V with 20 degrees of deadrise. The G3 did 54 MPH with a 70 HP direct reversing Mercury. To do this the motor had to be trimmed way out and it headed for the sky when the throttle was opened. It was the first commercial design that rode on its stern and produced a healthy rooster tail.
My surface drive points down 6 degrees and this buries the bow. Then it broaches to the left. I even tried twin rudders and a down angled hydrofoil on the stern but to no avail.
My first prop was a 3 blade 12"X 19. It would not stop ventilating. Then I understood what was required. At 5000 RPM I wasn't moving enough mass to plane the boat. The second prop was a 16" X 19 4 blade. The bigger prop hooked up at about 4000 RPM and tore your head off with acceleration. I could also have changed the gear reduction on the bigger prop for more power. This is cheaper than buying another prop.
The advantage of the Arneson drive is that you can lower the prop for grip to plane and raise it for speed to get maximum RPM. The ideal boat for this type of drive is the tunnel hull. The entrapped air lifts the bow and you go!
I worked as (civilian)for the Canadian Navy as technical authority for props, shafting and transmissions for our ships before I retired. I had a Naval Architect tell me that my Rube Goldberg junk would never work. It was gratifying to give her the ride of her life in a junk pile. ;)

[stupidbaker57]

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Here's some pics of my surface drive design. The boat is a 3 point shovel nose cab over. This is a mock up in wood to get a better eye on the degree of shaft angle. It will be braced by heim joints and bars.
The aluminum peices are cut and ready for welding.
There's enough clearance for an 8 inch prop if needed.
The rudder will be steered via conventional cables and pulleys.

[Willallison]

Here's some pics of my surface drive design. The boat is a 3 point shovel nose cab over. This is a mock up in wood to get a better eye on the degree of shaft angle. It will be braced by heim joints and bars.
The aluminum peices are cut and ready for welding.
There's enough clearance for an 8 inch prop if needed.
The rudder will be steered via conventional cables and pulleys.

I think you should beef it up a bit... those bits of timber look a bit flimsy...:P

[Grumpyrelick]

Here's some pics of my surface drive design. The boat is a 3 point shovel nose cab over. This is a mock up in wood to get a better eye on the degree of shaft angle. It will be braced by heim joints and bars.
The aluminum peices are cut and ready for welding.
There's enough clearance for an 8 inch prop if needed.
The rudder will be steered via conventional cables and pulleys.

Perhaps you might wish to review why you are doing this. Hydros are called 3 point hydros for a reason. They ride on 2 sponsons and the prop. Below a plane, the prop is sealed in the water by the bottom of the boat and ventilation of the blades can't occur. There is a slight chance that the prop will cavitate but usually the hydro is moving fast enough for easy transition to "prop riding". That is just another name for surfacing the prop. A prop running on the surface does not drag the strut or the hub through the water. Only the blades are immersed - and you can get away with a 2 blade on a hydro. A surface drive hanging off the stern will require at least 4 to 6 blades to overcome ventilation. My own boat only required an 8 in. dia. prop to plane with an outboard. My surface prop was 16 in. in diameter. Albert Hickman, inventor/designer of the Sea Sled and surfacing drive never considered the hydro shape. The stern of which is probably too narrow to plane easily. A catamaran or tunnel hull has the width to offer an easy to plane hull with the air entrapment advantage to lift the bow when at speed.

[stupidbaker57]

By my mesurements, my prop should be at the same point at the waters surface as a outboard on the same boat. An outboard when starting has it's prop well below the surface before it achieves full speed. The only thing different with my design (I think ) is that the engine has moved forward and the prop has moved to the rear 24 inches.
The real test comes in the spring.

[Grumpyrelick]

This may be true but the outboard has the benefit of what is called the cavitation plate which is actually an anti-ventilation plate just above the prop. You do not have this benefit. Further the outboard prop shaft is parallel to the water surface and draws its inflow from under the boat. The surfacing prop is at a serious down angle and will attempt to draw a prodigious amount water from between the prop and the surface. The required volume won't be available and will be replaced by air. If you are contemplating some sort of a U-joint for flexibility you will need a thrust bearing between the prop and the U-joint. This is discussed elsewhere in this thread. Remember that in designing performance boats the position of the machinery weight in the hull is very important. Further the weight of the propulsion equipment has to be kept as light as possible. A thrust beating, shaft, shaft log, strut and prop is all you need in a hydro. You will be carrying all this plus a U-joint, stern supports and a mechanism to raise and lower the prop. Note that as soon as you run a shaft out of alignment with the primary shaft (as in lowering the prop) you will get considerable side thrust and that means loss of power.

[stupidbaker57]

I'm useing the old theroy of K.I.S.S. I don't have a trimmable shaft tube (which has tapered bearing for thrust). The engine and drive will weigh approx. as much as an outboard of simular HP. This is a cab over style hydro that will have "moveable ballast" ME If the bow is light underway, I move my butt forward, and if it's too bow down, I'll slide to the rear of the cockpit. It's a kneeling position boat.

[Grumpyrelick]

The style of boat won't be an issue at speed. As soon as it planes you are on the sponsons. My own boat weighed less than 400, the motor close to 300 and me and the rest - about 1000 lbs. I had about 150 HP to play with. So 15 HP per 100 lbs.
The prop is a different story. The first prop I tried was a 12 X 19 pitch. It could fling a V-drive flat bottom across the water at nearly 90 MPH or pull half a dozen skiers. The boat weighed 2000 lbs and was over 6 ft wide with 430 HP. This same prop could not plane a 1000 lb boat 6 ft wide. It could not grab enough water to plane the boat. My second prop was 16 X 19. Note the pitch stayed the same but had about 1.3 times more surface area. Elsewhere in this thread there is a picture of a boat called Manta. Compare the size of the props to the width of the boat. They are very big.
A further consideration is the rudder. I doubled my rudders and still had trouble with with the stern walking sideways.

[IMP-ish]

Thanks for posing the photos and descriptions of your setup above.
I like the notion of engineering something like that for yourself.
Kudos.

[stupidbaker57]

I've been thinking and redesigned the drive. It will now be TRIMMABLE. This won't work for a lot of you guys, but for my small 11 foot boat, it sounds easy enough.
Instead of U joints, I thought I'd trim the whole drive train. The engine bed will share the same mount as the shaft tube and trim bars.
To increase the depth of the prop, lift the engine up at the forword end. The cradle is pivoted at the rear of the engine compartment. To increase speed, lower the engine in order to put the prop up near the surface.
I first made a wood mock-up of the cradle and then of steel.
Raising and lowering will be done by an acme screw and an automotive power window motor. Shifting the transmission will be done by a power door lock acuator.

Dave

[stupidbaker57]

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64516 I've been thinking and redesigned the drive. It will now be TRIMMABLE. This won't work for a lot of you guys, but for my small 11 foot boat, it sounds easy enough.
Instead of U joints, I thought I'd trim the whole drive train. The engine bed will share the same mount as the shaft tube and trim bars.
To increase the depth of the prop, lift the engine up at the forword end. The cradle is pivoted at the rear of the engine compartment. To increase speed, lower the engine in order to put the prop up near the surface.
I first made a wood mock-up of the cradle and then of steel.
Raising and lowering will be done by an acme screw and an automotive power window motor. Shifting the transmission will be done by a power door lock acuator.

Dave

[tom kane]

For decades the folks in Asia have been mounting a car engine , and a shaft on the stern of FAST small boats.

The prop is immersed fully as the boat is started and slowly lifted to surface drive as speed increases. The unit also pivots to steer the boat .A simple tiller controlls it all.

Should be really EZ to do with your engine , a heck of a lot fewer parts, and nothing in the water at rest.

Perhaps one of our fine members in Indonesia or ? could add a photo.

FF

The image shows the first outboard supplied to the public.The first long-tail boat in the Paris Exhibition c 1900`s. french colonies adopted them every where.

[stupidbaker57]

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66877Here's some more pictures of my progress. The cradle pivots just fine for trimming. The rudder is still being milled along with the jack shaft. Now the wiring needs to be done.

[Cawley]

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66877Here's some more pictures of my progress. The cradle pivots just fine for trimming. The rudder is still being milled along with the jack shaft. Now the wiring needs to be done.

Nice work! Keep us posted.

[gonzo]

Trimming a surface drive can be a really bad idea. It can make the boat get out of control. A proper setup should be able to be trimmed with the throttle. Also, it is really important to work the throttle properly when you go airborne so as not to lose control.

[Frosty]

Why do they make them trimmable then?

[Rik]

Trimming a surface drive can be a really bad idea. It can make the boat get out of control. A proper setup should be able to be trimmed with the throttle. Also, it is really important to work the throttle properly when you go airborne so as not to lose control.

Where do you come up with this stuff? Do you actually have experience or ?

If your idea is correct, then every I/O and Outboard should be fixed with no trim capability due to fear of the operator's thumb making the boat get out of control. Unfortunately no one would buy an I/O nor outboard without trim. Why do these matter? B/C they too can be configured as a surface drive, it is all a matter of the installed height. Likewise the same can be said of surface drives. The ability to trim has added benefits over the inability to trim.

[gonzo]

Once you have the trim set up, it doesn't need to be changed continuosly. Surface drives, with their long leverage, make changes more drastic. It should be possible to control the boat with throttle changes when you are goind downwind, for example. An outboard installed for surface propellers and an surface drives are quite different, because of the distance the propeller is from the boat. Early surface drives use to trim up to ventilate the propeller and unload it for the "hole shot". Now they are usually left down and ventilated with the exhaust or other means.

[stupidbaker57]

The reason for a trimable surface drive, at least on THIS boat, is this is a Hal Kelly design that glups in mass amounts of air at the front and compresses it to a point of lifting the transom considerably up. If the trim is fixed for one speed, it may not be right for a different speed, like comming out of a turn or heading into the wind.

[Frosty]

Once you have the trim set up, it doesn't need to be changed continuosly. Surface drives, with their long leverage, make changes more drastic. It should be possible to control the boat with throttle changes when you are goind downwind, for example. An outboard installed for surface propellers and an surface drives are quite different, because of the distance the propeller is from the boat. Early surface drives use to trim up to ventilate the propeller and unload it for the "hole shot". Now they are usually left down and ventilated with the exhaust or other means.

So the intricate hydraulics of the Arneson are no longer needed and the fixed type such as the Levi drive is preferable that accomodates for ventilation in its design,-- disregarding the financial savings?

[gonzo]

Yes, the Arneson is a complicated design. As with all technology, things get improved with experimentation.

[Rik]

Yes, the Arneson is a complicated design. As with all technology, things get improved with experimentation.

Once again, where do you get this stuff? So the throttle will change the boats attitude and engine load as well as speed regardless of everything else? You are stepping back in time and are tied to the problems of the past with this thinking.

[IMP-ish]

Arnesons dominate on fast poker run boats. Only reason I don't own a pair of arneson bravo conversions is the $$,$$$.

Kudos again on your DIY stupidbaker57.

[gonzo]

Rik: I understand that you want to promote your product, but it is complicated and not too appropriate for use by non-professionals. Arneson drives that stay in the water have seal failures from barnacles and other growth among other problems.

[IMP-ish]

Unlike a sterndrive, if the boot fails on an arneson it is not a problem. I don't know one boater who switched to arneson who switched back. I don't let barnacles grow on my boat. I keep it clean.

[fpjeepy05]

Rik: I understand that you want to promote your product, but it is complicated and not too appropriate for use by non-professionals. Arneson drives that stay in the water have seal failures from barnacles and other growth among other problems.

Rik promotes arneson and you promote cal500 (which doesn't trim)

At least Rik doesn't hide who he is promoting.

[Rik]

Rik: I understand that you want to promote your product, but it is complicated and not too appropriate for use by non-professionals. Arneson drives that stay in the water have seal failures from barnacles and other growth among other problems.

Oh noo... I merely asked where you get this information from? Your intent to deflect and avoid answering the question at hand while continiouing to make outrageos claims is perplexing. It only concerns me when someone starts to believe your mistruths as facts.

If you wish to promote the Cal 500 or whatever, here's a tip. :idea:Promote on what you have of value and avoid spreading mistruths about others in an attempt to make yourself look good as currently your experience or lack thereof makes you look :?::?::?::?:

[Cawley]

I agree.... If the package is capable of 35 knts +, the drives should be trimable. Also, the old Arnesons used to suffer from lack of bow lift. Now, the new 20 deg rake props have helped solve this problem. Back in the day we put a set of arnesons in a 38 cig. The boat did not have the bow lift and was always stuffed..... On a side note, most of the 200mph cats run the BPM surface drives, they of course, are trimable. Also, just because I don't have over 7,000 posts does not mean I don't know what I'm talking about. I prefer to spend my time in the shop, not on the computer.....
Thanks

[Frosty]

If the package is capable of 35 Kts or more they should trim!!! Well there a snippet of information I had not heard before and makes sense. That should throw some light on the trim-non trim debate. Non of our Gurus on the Forum brought that up before.

I have fixed 24x24 with pops sited 16inch from the transom , I need no ventilation and can hit 3000 RP in the marina if I wanted to, but then ide have to try to stop 14 tons.

Ive never felt the need to trim at my max speed of 24KTS. Twin 250HP with Hurth 630 A down 8 degree driving 2 inch shaft on 4 blade nibrals cleavers by Seafury.

( Factory boat is conventional with 300 twin and 24 KTS max.)

I reckon I'm in the 10% increase in efficiency they talk about.

Incidentally I told Seafury what boat I had and what I wanted they told me what engine G/ box and props to use.

If you buy a boat then an engine and a G/box and then ask what prop to use , they wont like you very much.

[Grumpyrelick]

Well, I didn't want to get into this one but since I have experience with assembling, out drive, outboard, jet, air drive, V drive, straight drive, and surface drive boats here is my 2 pesos:
1. You trim an out drive to "air" out the hull and reduce friction.
2. The same for an outboard. You also use a jack plate to reduce the drag of the foot or gearbox in the water.
3. You trim jets to lift the bow too for the same reasons.
4. My own experience found that air boats work best with the thrust line parallel to the keel.
5. V drive and straight shaft boats only benefit from trim tabs to improve take off and level the boat.
6. Now we come to surface drives. They are unique. When parallel to the bottom, they are almost clear of the water. So they only work in a down angle range. Therefore the drive will not lift the bow. All lift is provided by either an air entrapment hull or that the machinery, fuel and equipment is biased to the stern. The reason for the trim is so that a large pitch and surface area prop can be used. The boat is generally highly powered to get the boat on a plane. Once there, the prop is lifted to decrease the amount of blade hitting the water. This allows the RPM and the power to increase driving up the speed of the boat. Believe me when I say this: the hardest thing for a fixed angle surface drive to do is plane.

[gonzo]

The Sea Sleds were very successful with surface drives that were not trimmable. I think that a bit of trim can be useful for fine adjustments. However, it is often used to try to fix a bad design or installation.

[Grumpyrelick]

Albert Hickman's boats ran very large engines - engines that could run a 3 point hydro over 100 MPH. Albert's boats did about 60 MPH. He was so preoccupied with drag that his rudders were flaps that tucked into the stern. His hull design had a wide flat stern to help with planing. His props were wide "elephant ear" props for grip during transition to plane. These same characteristics doomed its top speed.
Aircraft can't alter prop diameters and they could not lift a load until they invented the controllable pitch prop. Surface drives can't alter pitch but they can alter how much prop diameter is in the water which amounts to the same result.
I also note that Hickman sea sleds are no longer sold...

[Frosty]

The Sea Sleds were very successful with surface drives that were not trimmable. I think that a bit of trim can be useful for fine adjustments. However, it is often used to try to fix a bad design or installation.

This is correct, the trim van be altered by the rake of the prop.

In surface drives you swing the biggest prop you can get on because when planing you have only half of that in the water.

When set up correctly and ventilated a fixed planes easily. I have one!

[Rik]

The Sea Sleds were very successful with surface drives that were not trimmable. I think that a bit of trim can be useful for fine adjustments. However, it is often used to try to fix a bad design or installation.

So only perfect installations or perfect designs lend themselves to a fixed surface drive. How does one find the perfect boat? Is this like finding the perfect women?

[stupidbaker57]

In responce to Arneson drives being $$$$$$$$$. Before I built my hydro, I had (and still do) a "cocktail napkin design" of an Arneson style built with auto parts from a wrecking yard. A gimble would be made from a front axle and hub of a front wheel drive car. I bought the "yard" parts for a future project. I would have gone with this set up first, but I wanted the hydro first, vee bottom later.

[Grumpyrelick]

Rake only moves the thrust point further back from the stern and allows changes to trim to be more effective. V-drives, straight shaft drives and ships do not usually have rake on theirprops.
The Arneson set up results in a heavy stern. The trim on this design is limited and will only lower the bow. as you cannot put positive trim on the shaft line because the shaft is above the water at speed. An in/out drive prop shaft is immersed and therefore the prop shaft can be trimmed above the parallel point to the surface.
Those who strive for simplicity and purity of design must put up with the drawbacks. Early performance sports cars were simple and could hug the road and corner well but on a long trip they rattled your teeth. Now performance cars have adjustable suspensions. Likewise boats. On a stormy day you can trim the bow down to pierce waves for a more comfortable ride so that the perfect woman passenger will continue to not bitch at you and remain "perfect". You want simplicity? Leave the "perfect woman" at home
Good hulls get better when there is more adjustment possible in the propulsion equipment. Poor hulls do not.