Pond Boss Forums Thread Like Summary - Stake bed construction

I have a bunch of non-standard size lumber. They are close to common 2" x 4" dimensions and anywhere from 8' to 10' in length. (They can't really be used as 2" x 4"s unfortunately as the dimensions vary too much. They are salvaged from packaging crates, FYI.)

I thought I would go ahead and use them to create a stake bed or two and then sink it in my pond. I also have some scurvy CMU's that I will use to weight the wooden stake beds. My questions are:

How many CMU's per 2" x 4", roughly, will I need to keep this apparatus from floating on me?

Assuming an 8' to 10' height, how close should I space the vertical 2" x 4"s?

TIA for any advice. I plan on building these and dragging them out on the ice here in the next couple of weeks and then letting them fall through the ice as it melts.

How many pond bosses does it take to screw in a lightbulb?:) Shove some of the 2x4's though the holes in the cement block and see how many boards it takes to float the block...

Ah, the question for the ages: experimental physics versus theoretical physics!

So, to make a safe calculation, calculate the volume of wood you will be using, convert that to U.S. gallons, multiply that number by 8.33 pounds per gallon... and you will have the weight it wood take to sink the structure (see what I did there? lol) This number will be more than you strictly need since wood has some weight to it already, BUT I would double the sinker weight number to make sure it sinks and stays put. OR, at least multiply it by 1.5.

If wood weighed 8.33 pound per gallon (in other words, 62 pounds per cubic foot) the wood would not necessary float or sink..it would just hoover around with the current. Once you find something that weighs more than water (8.33 pounds per gallon)...it will sink.

There are more scientific weighs to calculate the OP's question (see what I did there? lol), but the above will get you where you need to be without making your head and my head hurt.

RossC is on the right track, just not in his right mind. Just kidding around Ross!

A true 2"x4"- 8 foot long makes up about 3.5 US gallons of volume. That would be 29 pounds of water weight minus most of the actual weight of the 2x4x8'. An untreated white wood 2x4x8" weighs about 10 pounds. You'd need 29-10=19 pounds to make it not sink or float. 19*1.5= about 30 pounds. This wood make it sink well (I did it again).

RossC's 7.5 pounds per gallon is a mistake taken from "7.5 gallons per cubic foot". Don't feel bad Ross...I know this cause I have made the mistake myself.

There are 8.33 pounds per gallon of water, give or take some depending on the temperature of the water (if we get picky...lol).