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# Riptide — SLS-104 (Program ORCA)

**Public name:** Riptide  **Tracking #:** SLS-104  **Codename:** ORCA
**Category:** Surface Vessels (USV)  **Fiscal Year:** FY2024
**Contract award:** 02 August 2024

## Summary

Riptide is the high-speed interceptor USV — the sprinter to HERON's marathoner.
ORCA trades endurance for burst speed and maneuverability, built to close,
shadow, and (non-kinetically) interdict surface contacts cued by the wider SLS
fleet. The gap between SLS-101 and SLS-104 in the surface block is intentional,
implying cancelled or classified intermediate hulls.

## Notional Capabilities

- 40+ kt sprint; planing hull optimized for sea-state 3 intercept runs
- Cued autonomous pursuit and station-keeping off a designated contact
- Non-kinetic interdiction options (shouldering, blocking, hailing payloads)
- Runs the CEDAR (SLS-301) stack with an intercept-tuned maneuver policy
- Rapid launch/recovery from pier or mother-ship cradle

## Program References

- Kuwata, Y., Wolf, M.T., Zarzhitsky, D., & Huntsberger, T.L., "Safe Maritime
  Autonomous Navigation With COLREGS, Using Velocity Obstacles," *IEEE Journal
  of Oceanic Engineering*, 39(1):110–119, 2014.
  [IEEE 6519944](https://ieeexplore.ieee.org/document/6519944/)
- Salish Littoral Systems, *High-Speed Intercept Maneuvering for Unmanned
  Surface Vehicles*, SLS Technical Report TR-104, 2024.
- "The Branching-Course MPC Algorithm for Maritime Collision Avoidance," 2019.
  [arXiv:1907.00039](https://arxiv.org/abs/1907.00039)
- SLS Maritime Autonomy Group, *Cued Pursuit and Non-Kinetic Interdiction
  Behaviors*, SLS White Paper WP-ORCA-03, 2024.

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