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.