Reviewed August 2026
1. Purpose and Scope
This appendix records the engineering questions that must be answered before preliminary design becomes an acquisition baseline. It distinguishes objectives from fielded systems and preserves conventional fallbacks.
No class-level hydrodynamic, structural, acoustic, shock, stability, or lifecycle result is claimed without model-based and physical validation.
2. Common Architecture Versus Identical Hulls
The classes share interfaces, machinery families, software, logistics, and refit practices, not one underwater hull. Specialization controls hull form.
3. FFG Quiet-ASW Priorities
Machinery isolation, low-cavitation inflow, low-speed control, sonar self-noise, endurance, dual-helicopter support, and UUV/USV handling take priority over sprint performance.
4. DDG Maneuver and Combat-Power Priorities
Acceleration, turning response, electrical and cooling margin, radar siting, launcher distribution, and damage-tolerant combat-system operation drive the destroyer trade.
5. CAG Stability and Heavy-Load Priorities
Aviation operations, command spaces, heavy weapons, medical depth, freeboard, reserve buoyancy, roll control, subdivision, and growth margin drive the cruiser trade.
6. Bulbous Bow Trade
A long bulb may reduce resistance in a target speed band but can increase off-design drag, slamming interactions, structural complexity, and sonar-arrangement constraints. CFD and model testing must set the final geometry.
7. Deep Keel and Bilge-Keel Trade
Keel depth and bilge keels can improve tracking, structural continuity, and roll damping but add drag, draft, grounding exposure, and acoustic-flow consequences.
8. Stern-Form Trade
Transom, cruiser, and recessed stern forms must be compared for resistance, wake quality, aviation-deck support, launch and recovery, pod inflow, and damaged stability.
9. Recessed-Pod Stern Concepts
Costanzi-style or recessed pod pockets are objectives for study, not a selected certified geometry. They must not trap debris, amplify vibration, weaken structure, or prevent safe pod removal.
10. Shafts and Rudders Versus Pods
Azimuthing pods offer maneuvering and machinery-arrangement benefits. Conventional shafts and rudders retain greater naval precedent and constitute the required fallback until Odyssey passes qualification.
11. Counter-Rotating Propellers
Potential efficiency and cavitation benefits must be weighed against mechanical complexity, maintainability, signature, shock response, and supplier support.
12. Acoustic Performance
Objectives include resilient mounts, rafted machinery, quiet electrical operation, low-noise auxiliaries, flow control, and acoustic acceptance trials. Claims require measured source levels.
13. Cavitation and Wake
Pod and propulsor geometry must be tested across speed, loading, heel, turn, sea state, and damage conditions. Quiet-mode performance cannot be inferred from motor rating alone.
14. Shock and Battle Damage
Pod bearings, seals, cables, rotating interfaces, battery boundaries, switchgear, and machinery skids require naval shock, fire, flooding, fragment, and casualty-mode qualification.
15. Pod Removal and Maintenance
The proposed drydock swap must demonstrate access, lifting, alignment, sealing, connector inspection, test time, spares depth, and realistic dock-cycle duration.
16. Machinery Access
Sled replacement paths must preserve watertight integrity, structural continuity, exhaust routing, cooling isolation, lifting clearance, and safe maintenance without assuming every casualty fits a routine refit.
17. Integrated Electric Drive
Integrated electric propulsion is based on existing naval practice, but each TriSeadon plant still requires system-level power-quality, fault-isolation, motor-drive, electromagnetic-compatibility, and combat-survivability design.
18. Diesel, Turbine, and Battery Duty Cycles
Diesels support efficient low-to-moderate loads, turbines support high demand and sprint, and batteries support transients, reserve, casualty response, and bounded quiet operation. Dispatch logic requires full mission-load analysis.
19. Battery MW Versus MWh
MW is instantaneous power; MWh is stored energy. A stated 10 MW module does not establish endurance. Cell chemistry, usable energy, reserve margin, discharge rate, thermal limits, degradation, and hotel load determine quiet-mode duration.
20. Single-Fuel Policy
TriSeadon standardizes ship, aviation, boat, vehicle, and support-fuel demand around JP-5 wherever practical and operationally appropriate. Equipment certification and efficiency remain controlling constraints.
21. Armor, Subdivision, and Weight
Armor protects selected critical zones; it does not make the ship invulnerable. Weight, center of gravity, reserve buoyancy, fatigue, stability, access, and payload growth require a continuously controlled weight report.
22. Lifecycle Cost
Common equipment and swaps may reduce downtime, but savings must include spares inventory, refurbishment facilities, transport, test equipment, dock demand, obsolescence, and vendor competition.
23. Development and Test Requirements
- CFD, towing-tank, maneuvering, seakeeping, and self-propulsion tests
- Hydrodynamic, acoustic, cavitation, shock, casualty, and electromagnetic testing
- Full-scale endurance and maintainability demonstrations
- Land-based power, battery, controls, and combat-system integration sites
- Independent stability, weight, cost, and schedule review
24. Recommended Baseline and Fallbacks
Proceed with specialized conventional monohulls and integrated electric-drive design. Treat Odyssey pods as the objective pending hydrodynamic, acoustic, cavitation, shock, casualty, endurance, maintainability, and certification gates. Preserve a shaft-and-rudder fallback. Use mature generation and combat systems first; insert developmental systems only after qualification.