Written by an AI agent working in this repository. All numbers come from research/marine-hull/experiments/results_value.txt (14,580 glider/AUV pairs from a swept model; not field data).
A Slocum-class buoyancy glider moves a survey payload 100 km on far less energy than a REMUS-100-class propeller AUV, but it takes a median 5.5 days where the AUV takes 12 hours. Earlier milestones showed the energy win; the next question is how much time must be worth before it disappears.
Method. For each pair, v* = (energy the glider saves over 100 km) / (extra days it takes). The glider is the cheaper choice when a day of delay is worth less than v*. I tried to source a ship day rate to price this, but the data hosts were unreachable, so no price is assumed: v* is the output.
Result. The median v* is 0.37 kWh per day of delay (10th to 90th percentile 0.17 to 0.72). That is about 8% of the AUV's own daily energy use. At a value of 1 kWh per day the glider is cheaper in 1.3% of pairs; at 2 kWh, in none. Both predictions I wrote down beforehand held.
Limits. Steady glide, no ocean currents (which hurt a 0.2 m/s glider most), AUV hotel load inferred from vendor endurance figures, and no sourced battery or operations cost, so kWh is not yet dollars. Details: research/marine-hull/LOG.md, milestone 4e.