Summary: Motion decoys that create both movement and ripples on the water can be a tremendous asset on calm days. The motion decoy pictured to the left will put plenty of ripples on the water and provide the visible illusion of live duck feeding in shallow water. Here are the plans for you to build your own decoy and save a few bucks.
The heart of this motion decoy is the on-off pumping of the bilge pump, which causes the decoy to tip as a duck feeding in shallow water. This is done with a simple automotive flasher, the same device used to turn your trucks blinkers bulbs on-off. As the bilge pump and flasher are rated for 12V the starting battery for an outboard or mud motor will provide suitable power. A 12V rechargeable gel-type battery in the 6 amp/hr range will provide a mobile source of power.
Parts Needed
Optional Decoy Modifications
You can use the decoy as is or use a hacksaw to shorten the height of the keel. This will allow the decoy to operate in shallower water. The weighted part of the keel isn't needed as the bilge pump will provide this same balancing weight. Cut across the weight section of the keel about 1/8" down from the top. This will provide a flat surface to secure the base of the bilge pump. Do not cut across the thin part of the keel.
Attach Bilge Pump Base To Decoy
Now attach the base of the bilge pump to the keel with two #10 1/4" sheet metal screws. Do not over tighten, as the soft plastic of the decoy will easily strip. The bilge pump can now be inserted into the base.
Glue Tube To Pump
Coat the output tube of pump with PVC cement and attach 3/4" 90 degree PVC conduit tubing. Quickly align tubing per photo on top of this page as cement sets very quickly.
The top of the tube should extend about 1" above the bottom of the decoy and can be cut with a hacksaw.
Use blue butt connectors to splice your lamp cord to the pump. Cover the connections with heat shrink tubing. These connections could also be soldered if a soldering gun is available.
Finished Decoy
Now spray paint the entire pump assembly as shown with flat black and the decoy is finished.
Electrical Wiring
The electrical control and wiring of this decoy can be done quite simply as shown.
Use the female spade connectors to make the connection to the flasher module. Keep in mind we are switching the positive side of the power source to the bilge pump only. If using a switch as pictured at the bottom of this article it to will be placed on the positive side of the power source in series with flasher module. The negative wire of the bilge pump goes directly to the negative side of the power source.
DO NOT DELETE THE FUSE HOLDER Use a 20 amp fuse here.
Optional Enclosure And Switch
A very robust and economical enclosure can be constructed using a simple PVC enclosure intended to hold a light switch. This enclosure is just big enough to hold a typical light switch, flasher, and fuse holder. Wiring exits out the bottom of the enclosure. This will add about $6 to the total cost.
Notes
For controlling one decoy a standard flasher can be used. When using 2 decoys a heavy duty flasher should be used. If you want to control several decoys with the same flasher a "solid state flasher" available at most automotive parts stores is recommended.