Complete the sentences with the correct verb form.

1. The Navigating Officer (receive) weekly updates to the electronic charts via e-mail.

2. Electronic chart permits (obtain) electronically with minimum data usage.

3. If the radar overlay (not turn on), the vessel will just not be seen on the ECDIS display.

4. Conventional nautical charts (print) on large sheets of paper at a variety of scales.

5. Since centuries navigational paper charts (be) the heart of ship navigation.