SM-13's Top/Average Speed
@retrograde-raven a gift for you
Skimmed through the movie and found three decent close-ups of the coordinates while the SM-13 is in motion. Timed it out with a stopwatch and documented the coordinates so I could calculate the distance traveled. The shots are only about 2-3 seconds each, but it's enough to work with.
00:35:56
time: 1.71 seconds
coordinates: 453.30, 247.80 → 453.58, 247.75
distance traveled: 0.284 meters
velocity: 0.166 m/s or 0.598 km/h (0.372 mph)
01:00:51
time: 2.83 seconds
coordinates: 927.62, 802.36 → 925.58, 799.82
distance traveled: 3.258 meters
velocity: 1.151 m/s or 4.144 km/h (2.575 mph)
01:19:15
time: 1.8 seconds
coordinates: 383.88, 614.82 → 382.19, 614.93
distance traveled: 1.694 meters
velocity: 0.941 m/s or 3.388 km/h (2.105 mph)
I'm counting the velocity taken at 00:35:56 as an outlier considering that the SM-13 was going up a considerable incline and was likely struggling. So based on the latter two velocities, the SM-13's average speed is 3.766 km/h, or 2.34 mph, top documented speed is 4.144 km/h or 2.575 mph. About 2.03 and 2.24 knots in nautical terms.
May not seem too impressive, but the Deepsea Challenger (manned submersible that reached the deepest known point on Earth) has a top speed of 3 knots, or 5.56 km/h (3.45 mph).
It's possible that the SM-13 is capable of higher speeds; the movie just doesn't give us enough data to say for certain. I'll keep an eye out for any other usable shots of the coordinates and update this post with any other evidence I come across.
