When placing a boat of any type (including boats with chests), they face the direction of the player, then snap to a less precise direction. This is helpful to face them in a cardinal direction, however they do not face north (±180°), only east (-90°), west (+90°), and south (0°).

What I expected to happen was...:
When the player is facing a direction very close to north (±180°), the boat placed should face exactly north.

What actually happened was...:
The placed boat faces a new position, ±178.6° every time.

Steps to Reproduce:
1. Obtain a boat or boat with chest
2. Face a direction very close to north (greater than +179° or less than -179°)
3. Observe the boat entity's facing direction/yaw (NBT: Rotation[0])

Video attachment on Google Drive: Boat placement shown for north and south orientations. Note the second line of text under the minimap shows facing directions identical to the F3 debug menu.