The three columns represent the left bank, the boat, and the right bank respectively. The < or > indicates the direction of motion of the boat.
The fox, the duck, and the corn
fdc . . fc d> . fc < d f c> d f <d c d f> c d < fc . d> fc . . fdc
Three missionaries and three cannibals
mmmccc . . mmcc mc> . mcmc <m c mmm cc> c mmm <c cc mc mm> cc mc <mc mc cc mm> mc cc <c mmm c cc> mmm c <c mmmc . cc> mmmc . . mmmccc
Three humans, one big monkey, two small monkeys (Dudeney, Puzzle-Mine, #164)
HMhhmm . . Hhhm Mm> . Hhhm <M m Hhh Mm> m Hhh <M mm hM Hh> mm hM <Hm hm hm HM> hm hm <Hm hM mm Hh> hM mm <M Hhh m Mm> Hhh m <M Hhhm . Mm> Hhhm . . HMhhmm
Three jealous husbands and their wives
ABCabc . . ACac Bb> . ACac <B b ABC ac> b ABC <a bc Aa BC> bc Aa <Bb Cc ab AB> Cc ab <c ABC b ac> ABC b <B ACac . Bb> ACac . . ABCabc