Blaine, even a backhoe with an extend-a-hoe wouldn't reach out that far. You are looking at an excavator for that type of reach. I'm at a loss unless you can get a portable pile driver.

Maybe rig up a tripod and find one of those old weights that they used to drive shallow wells??

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).