Crash Dive 2 campaign waypoints
 

The ETA given on waypoints doesnt seem to add up. As the sub approaches a waypoint the ETA seems to increase instead of decrease? For example i set a way point and it tells me my ETA is 14:00 but as i move towards it, it begins to day 14:01hrs, 14:02 etc instead of 13:59, 13:58, am i just not understanding it?

Also is there any way to start a campaign submerged if its daylight instead of stopped on the surface? Or change the start time of day of a campaign mission?

ETA is your Estimated Time of Arrival, and should remain the same as you head toward the waypoint unless you change speed; it's based on your current speed, and will be constantly updated.
So if you slow down, the ETA should increase; if you speed up, it should decrease; otherwise it should be more or less constant (weather changes can also affect your speed if you're surfaced).

"Travel Time" shows the approximate time remaining to reach the waypoint, and should constantly decrease as you approach.

The time of day is random because it's after your travel from your home port, which may have taken a few days. You always start surfaced because I make sure there are no enemies within visual range when you arrive. If you want to start your patrolling at a particular time, just use the "Wait in Place" tool to loiter until whatever time you choose.

Hope that helps!