Medium sized Duplo-compatible boat with optional keel

thingiverse

This boat model boasts a slightly larger size and Duplo compatibility, ensuring stability through a keel brick. Note that the figure and lion in the photo are not included with the set. To weigh down the keel, a couple of long M5 bolts are required. The hull is constructed using two thin layers with gaps for drainage at the rear; however, this design may allow water to accumulate inside.