One thing that needs to be taken into consideration is how dry the wood is. A 2 x 4 x 10 that is kiln dried will need more weight to sink it than a sopping wet treated 2 x 4 x 10.

https://www.builderscalculator.com/lumber-weight-calculator/

Start at page 3 of the following chart:

https://www.fpl.fs.fed.us/documnts/fpltn/fpltn-218-1931.pdf

www.hoosierpondpros.com


http://www.pondboss.com/subscribe.asp?c=4
3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).