Here's a complete, standalone HTML page with the full 10-year cost comparison. All figures are current-dollar estimates with clearly labeled assumptions you can tweak. Headline result: **~$1.16M all-in 10-year net cost for the seastead vs ~$2.26M–$2.72M for the three comparable yachts** — mostly driven by the lower purchase price and near-zero energy cost, partly offset by harder-to-predict resale and insurability.
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10-Year Cost Comparison: Seastead vs. Catamarans & Trawler
10-Year Cost Comparison — Custom Solar Seastead vs. Comparable Production Yachts
Scenario: a Digital Nomad living aboard full-time in the Caribbean for 10 years,
anchoring or tension-leg mooring (no marina slips), powered entirely by solar + batteries.
All figures in today's dollars; inflation, financing costs, import duties/taxes, food, and
personal expenses are excluded.
Key assumptions
Interior area matched: all four vessels provide roughly 800–860 ft² of enclosed living area
(the seastead's 44 ft equilateral triangle ≈ 838 ft²).
Fuel: Caribbean diesel averaged at $4.80/gal.
Marina nights: ~40 nights/yr for storm holes & provisioning at ~$220/night (the seastead
cannot fit conventional slips; assumed 10 nights of shipyard/lay-along time).
Insurance: production yachts ~1.1–1.2%/yr of hull value; seastead priced higher (~1.2%/yr)
due to novel-design underwriting risk. If uninsurable, treat this row as self-insurance reserve.
Resale at year 10 (before selling costs): sail cat 45%, power cat 42%, trawler 52% of new price;
seastead assumed at 35% (range tested below). Selling costs (brokerage/marketing/survey) = 8% of gross.
Batteries: LiFePO₄ reserve of $8k/yr amortizes one mid-life pack augmentation (~year 8).
Purchase assumed cash; survey/closing/delivery-to-Caribbean added once at acquisition
(seastead ships in its single 45′ HC container; assembly assumed included in its sale price).
Seastead notes: no fuel (solar/electric), but higher underwater-diver reliance since a 44-ft-beam
vessel rarely hauls out; battery pack reserve included; permit line padded for novelty-of-design paperwork.
Capital Costs, Resale & 10-Year Net Cost
Item
Seastead
Sail Cat (Lagoon 55)
Power Cat (Aquila 54)
Trawler 60′
Purchase price (new)
$1,000,000
$2,250,000
$2,600,000
$2,800,000
Survey, closing, delivery to Caribbean
$5,000
$45,000
$45,000
$45,000
Operating costs, 10 years
$475,000
$900,000
$1,080,000
$1,010,000
Residual value at year 10 (% of new)
35%
45%
42%
52%
Gross resale value
$350,000
$1,012,500
$1,092,000
$1,456,000
Selling costs (8%)
−$28,000
−$81,000
−$87,360
−$116,480
Net proceeds from sale
$322,000
$931,500
$1,004,640
$1,339,520
Net 10-year cost of ownership
$1,158,000
$2,263,500
$2,720,360
$2,515,480
Effective cost per year
$115,800
$226,350
$272,036
$251,548
Effective $/ft²/year (of interior)
$138
$266
$340
$293
Visual Summary — Net 10-Year Cost
🟢 Seastead
$1.16M
🔵 Sail Catamaran
$2.26M
🟠 Power Catamaran
$2.72M
⚫ Trawler 60′
$2.52M
Bar lengths scaled to the highest (power catamaran) value.
Seastead Resale Sensitivity
The biggest uncertainty for the seastead is residual value — there is no established resale market for a
one-off design. Net 10-year cost at different exit values:
Year-10 resale
Net proceeds
Net 10-yr cost
25% ($250k)
$230,000
$1,250,000
35% ($350k) — base case
$322,000
$1,158,000
45% ($450k)
$414,000
$1,066,000
Scrap/value of components only
~$50,000
~$1,430,000
Where the Seastead Wins / Loses
Wins: purchase price (less than half of any comparator), zero fuel bills,
low mechanical complexity (sealed rim drives, no through-hulls, triple-redundant power), no slip fees ever.
Watch items: insurability of a novel
design; few yards can lift a 44-ft-beam structure (plan for crane slings / beach maintenance); resale liquidity;
permitting as an unusual craft in some islands; single-point-of-failure yard dependence for major steel/aluminum work.
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A few notes on judgment calls I made (easy to edit in the file):
- **Vessel picks:** Lagoon 55, Aquila 54, and a Nordhavn/Selene-class 60′ trawler were chosen because their enclosed living areas land near the seastead's ~838 ft². Their new prices run 2.2–2.8× the seastead's, which is realistic given production fit-out vs. your simpler aluminum/panel construction.
- **Insurance is the wildcard for the seastead.** I priced it at parity with production boats, but some underwriters may simply decline a novel trimaran-semi-submersible. If self-insuring, move the $12k/yr into the contingency line.
- **No haul-outs assumed for the seastead** — a 44-ft-beam object won't fit most travel lifts, so I budgeted recurring diver services plus periodic antifoul instead. Worth engineering bolt-on lifting points anyway for the day you do need a crane.
- **Trawlers hold value best** (52%), which is why the trawler beats the power cat despite costing more upfront. The seastead's base-case 35% residual is honestly speculative — the sensitivity table brackets the downside (scrap value ≈ $1.43M net cost, still cheapest of the four).
Want me to add a version with financing (loan payments) or import duty scenarios (e.g., BVI 5%, Bahamas 10% VAT) as toggleable columns?