4th year rink builder in Minneapolis/St. Paul, but at a new house this season and thus have a different setup.
Boards are 2' high plywood with wood stakes.
Rink is 28 x 52.
16 inches in the deep end, 4.5 inches in the shallow end.
Previously my deep end was just 12 inches and wood stakes were always plenty of support.
I flooded on Thursday night into Friday and all was well. I've since noticed some fairly significant bowing or, more accurately, leaning of the deep end boards.
I pounded in 20 pieces of 4' rebar this evening so have 2' under ground and 2' in contact with the boards.
I have to believe that this will be plenty to keep things from getting worse or downright failing, but I'm looking for someone to concur!
Photos attached...please have a look and let me know what you think.