Khutla: Boat Trip Relay

Khutla gives a small-boat crew one deliberate action to start a trip and one action to mark the boat back ashore. The travelling phone records its own trip, compresses the position history with a stated error bound, seals it, and carries it locally.

When two Khutla phones pass within direct radio range, they compare compact bundle summaries and exchange only the signed records the other phone lacks. A short contact can therefore move a boat's encrypted trip evidence from one carrier to another even when neither phone has mobile data. Carrier phones can verify the seal and custody state, but cannot read another boat's coordinates.

Whichever carrier later reaches a network can deliver the opaque bundle to a linked shore phone through a limited-retention relay. Shore acknowledgment then travels back through later carrier contacts, confirming delivery without exposing the track. A person may also open their normal SMS app with a compact retrieval reference as a last hop; Khutla never sends an SMS automatically.

If an active trip passes its stated return line, the linked phone uses the latest delivered evidence to calculate a widening probability field. A deterministic drift ensemble combines elapsed time, movement-derived current and wind estimates, leeway uncertainty, and the last known position. Khutla ranks 250-metre cells by probability relative to estimated search effort and presents the first three places to cover. It shows an area rather than a location pin because the available evidence cannot prove one exact position.

Key functions:
• One-action departure with an expected return time
• One-action return that creates a terminal signed receipt
• Compact trip records with Douglas–Peucker simplification and delta-varint encoding
• Direct store-and-carry exchange between nearby Android phones
• Signed, encrypted bundles with resumable chunk transfer and custody counts
• Linked shore delivery through a short-retention Cloudflare relay
• Ranked search cells that expand honestly as uncertainty grows
• Optional App Lock with independent biometric and Khutla PIN methods
• Local controls to delete trips, carried bundles, links, and keys

Khutla does not show a live fleet map, track people, send automatic alerts, contact authorities, or predict weather. It is a trip-evidence and search-planning tool, not a substitute for proper marine equipment, local procedures, or professional assistance.

No account is required. Positions belong to a boat's own trip, expire, and remain encrypted while carried by other phones and the relay.