And do NOT try to place them by yourself, from a canoe. It can get hairy, and wet.
Cmm
Sounds like the voice of experience???
Any photos to go along with that visual?

My buddy and I decided to sink some pallets, 3 tied together. Took them out with the boat along with several cinder blocks to set on top of them to sink 'em. One by one we added the blocks, watching the pallets begin to teeter the more weight we added. When it was needing one or two more to finally sink, the pallet tilted and all the cinder blocks slid right off down to the bottom of the pond.
Up sprung the pallets

So now there's a nice pile of cinder blocks.
2 piles, because we tried and failed again

Stupid is as stupid does? In our case, yes, but we certainly had some good laughs in the process, and thankful no one was watching
Yet interestingly, over the past year the pallets have still not sunk but are 90% submerged (anchored with one cinder block) and has been a great LMB hangout!