The boats where officially made for a marble olympics idea, they float on water and are great as bath toys.
They can carry up to 4 marbles of 16mm and are fairly stable.
The raft is made to sustain rough water, the canoe can tip over so don't lose your marbles in the tub.
A nice toy to print for next to your rubber ducky in the tub!
generic PLA, ABS, PETG