Your plan covers the core engineering and build path very well. Below are major steps and sub-steps that are commonly missing from early-stage marine/floating-structure projects, grouped roughly by where they fit in your existing roadmap.
Before committing to a "trimaran yacht" classification path, have a written pre-consultation with the intended flag state (Anguilla, Panama) and a classification society (e.g., Bureau Veritas, Lloyd's, RINA). A 39-ft equilateral triangle with 7-ft walls is unusual; getting an early opinion on category, tonnage measurement, and required surveys can save major redesign later.
Even prototypes need hull, P&I, and liability insurance for sea trials. Some underwriters refuse novel hulls. Get a non-binding indication of insurability before you build, because insurance often dictates classification requirements.
In addition to CFD, do a formal intact & damaged stability analysis (GZ curves, IMO/ISO criteria). Small-waterplane designs can have unusual righting-arm curves. This is also required by most flag states.
Run a systematic FMEA on: leg flooding, single-thruster failure, dual-thruster failure on one leg, mooring line failure, solar/battery fire, dinghy davit failure, stabilizer jammed full-deflection, etc. This is cheap on paper, expensive at sea.
Each leg should have independent bilge pumps and leak sensors reporting to a central display. Fire detection in battery compartment is essential.
For a China-built kit: define inspection hold points, NDT requirements for welds, material certificates (especially for the foil-shaped legs), and a third-party inspector. Shipping container loading plan and customs paperwork should be prepared 3+ months ahead.
Anti-fouling, sacrificial anodes, ICCP system?, paint schedule, and inspection intervals. The RIM thrusters are particularly vulnerable to biofouling.
Whether Anguilla or St. Maarten: confirm crane capacity, quay space, power, water, security, and weather windows. Have a written agreement before parts arrive.
Write a proper Operations Manual: startup/shutdown checklists, emergency procedures (man overboard, fire, flooding, loss of power, hurricane prep), maintenance schedule. Required for insurance and class.
The Caribbean has a 6-month hurricane season. Plan options: (1) sail south of the belt, (2) haul out, (3) ride it out on tension-leg mooring with specific procedures. Each option has design implications you may want to lock in now.
Helical mooring screws into the seabed require environmental permits in most jurisdictions (seagrass, coral). Anguilla and Panama waters both have protected areas. Get this clarified early.
Selling units to customers requires more than a one-off classification. Plan for CE marking (Recreational Craft Directive if selling in EU), USCG compliance if selling in US waters, etc.
Customers will be in remote locations. Define a spare-parts kit shipped with each unit, a service partner network, and a remote-diagnostics capability.
Since the vision includes connectable seasteads forming a community, define early: how do clusters anchor together legally? Whose flag flies? How are disputes resolved? This is part of the product, not an afterthought.
Total cost of ownership: build cost, mooring fees, fuel/energy, maintenance, insurance, depreciation. A clear TCO model is a major sales tool.
The foil-leg + servo-tab-stabilized airplane fin combination is novel. Consider provisional patents before publishing too many details, or deliberately publish to prevent others from patenting (defensive disclosure).
You mention YouTube in step 8.3 — formalize it. Documenting the journey builds the customer pipeline for step 10 and can attract additional funding.
Maintain a living document of identified risks, mitigations, and key design decisions with rationale. Invaluable when the naval architect, shipyard, and class society all ask "why did you choose X?"
None of these change the technical concept — they protect it. Most are cheap if done early and very expensive if done late.
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