Posted coordinates bring you to Pottawattomie Park.
Here you will find a sign you will need information off of. You will also need to look around the surrounding area.
The only way to get to the final is by kayak, SUP, or some other water based conveyance.
If you google the final coordinates it looks like they are on land but let me assure you it is not.
You will find the container at N 43 01.ABC
W 086 11.XYZ
A= # of letters in the 6th word on the plaque.
B=Last # in the year
C=Name of township - 1
X=# of benches at playground
Y= Name of park -4
Z=# of picnic pavilions + 2
The park as far as I can tell is the closest place to launch your watercraft.
Final container is a preform. Please do not remove it. Just remove the log, sign and replace.