Player can look behind in a boat

While driving a boat, the player is only supposed to be able to see within the 180 degree arc in front of the boat. In 0.16.2, players can look behind as well. This used to work correctly in 0.15.10. (See the screenshot of a possessed Alex)

Also, as a likely related issue, the players can hold and use other items while rowing. If you think these issues are irrelevant I'll open separate issues for them.