Several years ago when we had a long dry spell Lake Okeechobee's water level receded. Around the lake buried in the mud several cypress ( dugout ) canoes were found.
If memory serves me they were dated back during the time of the Seminole Indian wars and even before then.
Common practice in the Lake Okeechobee area ( back then ) was to sink the canoe. Especially during the Indian Wars when you did not want anyone to know where you are. Seamed like a good way to keep anyone from finding it or using it.