When you fill the boat with chest with anything inside the container and then copy the boat with chest by pick blocking, you are unable to copy it. This is inconsistent with other transportable containers such as chest minecarts.

How to Reproduce
1. Place a boat with chest.
2. Fill anything inside the chest.
3. Copy it by using the Ctrl+Middle scroll mouse to pick block copy.

Expected Result
The boat with chest is copied and can be placed as a separate boat.

Observed Result
The boat with chest is not copied instead it picks the normal boat with chest that contains nothing.