| The retractable masts viewed from bow to stern are the periscopes, radar antennae, radio and satellite communications and navigation masts. |
| When disturbed, they dive headfirst under water, or they sink slowly into the water until only their heads are above water, like submarine periscopes. |
| As you descend, your first sight of the submarine will be a selection of masts and periscopes rising from the conning tower. |
| The gunner's station is equipped with gunner's main sight, three periscopes and a visual display unit. |
| You can see the eel's entire length through the gaps in the planking, just aft of the conning tower with its two periscopes. |
| Since mines don't emit sounds, produce heat, make transient sounds or poke periscopes through the surface of the water to attack their prey, minemen have to look for shapes. |
