Distance of an interception - math help needed

[lucklucky]

Assuming French FREMM frigate bridge is at 15m altitude, then that gives a 13.8km horizon. I know there is a formula of percentage of distance of an object at sea(when the drone is downed) from the observer to the object and the horizon line but it was long ago and i don't have it anymore. Any help?

To know the aprox. distance of the hit.

Edited April 22 by lucklucky

[DB]

Without knowing the height of the drone, the solution is not constrained. The angle thing would work for a surface target, because the surface constrains the altitude.

Sorry, though, I'm guessing from the geometry, I don't know the equation.

[sunday]

There is the splash of the drone debris, at the surface, but still the angle is quite unknown.

[KV7]

By my estimation this intercept was at around 700 metres or 1100 metres, these are based on the time to target and visual estimation of range to bracket to these two estimates corresponding to two shells 0.5 seconds apart (from 120 rpm of the gun).

Altitude was around or somewhat above 45 metres based on a time of fall of 3 seconds.

This may be wrong as it is a quick back of envelope attempt.

Edited April 23 by KV7
More details

[lucklucky]

19 hours ago, DB said:

Without knowing the height of the drone, the solution is not constrained. The angle thing would work for a surface target, because the surface constrains the altitude.

Sorry, though, I'm guessing from the geometry, I don't know the equation.

It is irrelevant.  The drone falls at sea and it is visible floating.

[DB]

Ah yes, point well made.