To make a dredge, you could probably do it with PVC. Look at this design, and basically replicate it with PVC. Diving Equipment Specialties
The key to making the dredge work is making a venturi elbow above the suction nozzle. You could probably assemble that out of a trap from a toilet drain.
While using a scooter does work for uncovering larger items, its MUCH MUCH slower than dredging. Even if you use a relatively low GPM pump to power the dredge system, it makes good suction if you create the venturi properly.
The key to making the dredge work is making a venturi elbow above the suction nozzle. You could probably assemble that out of a trap from a toilet drain.
While using a scooter does work for uncovering larger items, its MUCH MUCH slower than dredging. Even if you use a relatively low GPM pump to power the dredge system, it makes good suction if you create the venturi properly.