Thank you for your point. We are on a channel off of a bay in the Great Lakes...so large waves are not an issue. However, 20 years ago water levels were so high that flooding over the top of the seawall was a possibility and may again be an issue in years to come.
Stone has been backfilled...
Sorry, misinformation provided. Deadmen are 2'wide by about 8' high. Also, your point about seeking competent engineering locally is well taken. Unfortunately, the largest and most used engineering firm in this small town is the engineer who designed the seawall.
I fess up that I am not an engineer. I own a channel lot. 70' of channel frontage. Steel sheetpile wall, clay soil, 24" by 12" sheetpile deadmen every 10 feet 18' back from wall. Two 3/4" tie rods from sheetpile wall welded to each deadman, unfortunately not threaded and bolted...
