DIY Boat Prop Current Device

[Jimbo]

Hi here are some not so clear pictures of my boat prop current device. Some considerations are as follows...

1. 1.5 inch boat prop, a smaller prop might be better (tammy's hobbies, beaverton or)
2. 3000rpm c frame fan motor .38 amp(http://www.outpost.com/product/2478890)
3. I used a ball point pen casing for the shaft and to cover the fan motor shaft to prevent salt corrosion. The lower bearings are made of nylon. Used orings/rubber grummets to keep things in place (ace hardware)
4. Packed the bulkhead that is attaching the fan shaft with silicon grease. This prevents salt water from flowing back onto the motor.
5. I tapped and drilled the piece of plexy that has the outside holding shelf and used stainless steel bolts (on the outside, home depot)
6. Flat drive belt bought from electronics store (Norvac in beaverton OR) or you can get them from a vcr/tv repair shop. Tension if very important, if it's too tight the motor won't turn or will turn slowly. The belts I bought where a little tight at first but after a day of breakend the motor is spinning at nearly full speed.
7. The motor gets hot so you might want to mount a fan blade on the outside shaft. I had one, but I kept knocking it off Need to find some glue that will hold it to the shaft, maybe jbweld or liquid nails will work.
8. all shaft bearings are pressure fitted. When they wearout they will be easily replacable.
9. If I mount the device on the rear wall it generates enough current to push the sand around. If it is mounted on the side of the tank pushing over the length 3' it just pushes water.

I used harvey's mp-6 cement to glue the plexy pieces together. I have abused this unit and it has still held together. This is just a prototype, I'm working and a redesign for a second unit.

Cost of parts and glue to make 2 devices is about $20 including sheet 1/4" plexy.

Hopefully I can get the exact piece dimminsions. Want to do a redesign first though.

[Jimbo]

second set of pictures

[Doug1]

Kewl Jimbo, so the motor is above , its belt drive? Kinda like a "Evinreef"

[RWD]

Jimbo,
I have been following along with your posts on these wave making ideas and I think you are on the right track. In the back of my head I have been going through different types of "systems" to generate massive amounts of back and forth surge. Someday (yes someday, maybe never ) I plan on building a larger reef system that would incorperate such a system. One idea I can remember from a looooong time ago was a guy posted on Aqualink, maybe 6-7 years ago. He somehow mounted an electric trolling motor in a plastic milk crate (I believe). Don't laugh, it sounds like it would work! Anyway I think he used some sort of electronic speed control to puls the thing on and off. That's all I can remember for now. I'm not sure how long the motor would last and you would need to use one that was saltwater safe. Good luck, Bob

[Geoff]

very nice!! it is surfing time.

G~

[dattack]

I am really impressed. Great job.

Are you getting noticeable current with this wavemaker?

And is that a left or right handed prop?

[Jimbo]

Standard left handed prop. It generates alot of water movement in all directions. Not like a powerhead where the water is focused. Of course you can glue a large piece of PVC over the prop to direct flow and/or use a smaller prop, I bought two smaller ones to try out. I droped some DT's in front of the impeller and it spread out all over the tank almost instantly. I'm going to add a second unit and remove the powerheads, the powerhead is going into an autotop off system . With the motor having two shafts it's easy to reverse it. some motors you have to take apart if they only have one shaft and reverse it, not that big a deal though.

I'm getting some slippage on the flat band, seems to be working now, but a small square or round belt works well if you use two rubber grumets and put the belt in the grove at both ends. Thats probally what I'm going to have to do with this unit. Like I said it's a prototype so still learning what is the best configuration.

Hope this helps

[Casey]

way cool JIM

[Jimbo]

I had to dump the flat drive belt. Went to a small square belt that fits in the grumets groove. Look at the bottom picture and you can see the grumet, there's also a small oring. Using the small oring creates less friction vs the grumet rubbing on the bearing. I also dumped the yellow propeller and went to a blue one, slightly smaller. I hated the look of the yellow one, stood out too much.

I think it was Geoff that suggested some sort of tunnel around the prop. The water fans out at about 50 degrees in all directions so you don't see hi current, just alot of water movement. But it may be a good idea to funnel the flow some. Wonder where I can get some clear pvc tubing, not sure what the designation is. Prefer to buy it locally if possible. Guess I could go to petco and buy one of those cheap sander skimmer and cut up the tube. Hay that would also be a good idea for a DIY calcium reactor.

[Geoff]

i like the gromet idea. that should keep the slipping down and allow you to ease the tension a little to help the motor.

acrylic tubing

if you have a plastic supply place around you, they should also have the tubing.

G~

[Jimbo]

Finally figured out what the extra wire is for. Red & White= low speed Black & White = high speed LOL. Not sure why I did not notice this before. Could have had to much drag, I think I connected the black and red wire when I first got it and the winding cover was melting, so once I had it working without getting that hot, did not want to ruin it, fry's is 45 minutes away . The thing definitly pushes all kinds of water now. Don't see the need for directional cover at this point, but on a larger tank you might want that.

The upper gromet in the picture above split into two pieces so I just sandwiched the belt between them. I don't believe the pen shaft is going to last so would like to replace it with a glass one and glass or some tuff substance for the bearing. This way the only part that could wear out would be the belt. Can use my dremel tool to ruff up the surface where the belt will be on the glass shaft. Maybe a fiberglass cover for the motor shaft.

I have an adjustment for prop position, but moving it changes the relationship of upper and lower shafts twisting the drive belt. It would be nice if the whole unit on the top could easily be rotated. Of course a longer shaft motor would be nice so it can be located farther out from side of the tank, would need to find a supplier for such a motor or putting a shaft extender on it. I've been thinking about mounting the next motor upside down so it does not stick up so high. This would require cutting the acrylic so the motor head could dip down, The whole outside unit could be made of black acrylic, so it does not look so cavemanish.

Oh Thanks for all the enthusiasm from all of you, has made this project enjoyable to be able to share

[dattack]

Can you make me one?

[Jimbo]

Sure can make them for people, been looking at tools for doing a more professional job. beta units for $35 w/extra belt. Remember you will be a beta tester. So your unit might need some tweaking the beta units will be a little rough looking, but will function. I can also get .60 amp motors, thinking they will need two belts to cut down on slippage.

Send me an email if your interested.

[Jimbo]

A update :

Not happy with the way the drive belt is working, having slipage problems, it also seems that the belts are deterating faster than I would like. If it last months that would be acceptable, but it only looks like weeks. Ordered a kevlar timing belt and gears, this should solve this problem once and for all, but adds $10 to the cost of the unit.

Glueing such gears into place will probally be a problem. So need to be pressure fitted. I'm toying with the idea of making my own drive shafts out of fiberglass. With a small lathe it would be easy.

Have a great day !

[dattack]

Maybe you should get it patent when you are done.