A group is on a canoe on a river.
A few people are in rough seas on a small boat.
The canoe is on a river, not the ocean or sea. The river could be calm or flowing, but not necessarily rough. A canoe and a boat are very different things.
exists p1 x1.(exists x2 x3.(on(x1,x2) & on(x2,x3) & n_river(x3) & n_canoe(x2)) & n_group(x1))
exists p1 s1 x1.(exists s2 s3 x2 x3.(in(x1,x2) & on(x2,x3) & n_boat(x3) & a_small(s3) & Theme(s3,x3) & n_sea(x2) & a_rough(s2) & Theme(s2,x2)) & n_people(x1) & a_few(s1) & Theme(s1,x1))