Ship and Boat Building (United States) — NAICS 3366

A Histometrics rollup primer for public-market and private investors. NAICS = North American Industry Classification System, the U.S. government's standard industry code. This is the 4-digit "industry group" level. It has exactly one child — the 5-digit industry 33661, Ship and Boat Building — so this page is a short pass-through. For the full treatment, read the 33661 primer; this page confirms the level equals its one child, states this level's own ground-truth federal figures, and points you onward.

1. Overview

NAICS 3366 is U.S. waterborne-vessel manufacturing. Because the 4-digit group contains only the single 5-digit industry 33661, the two codes describe the same economic activity and carry the same federal statistics — there is no other industry rolling up here to blend in. The one useful thing to know at this level is that the code is really two opposite businesses filed together: government-funded ship building and repair (a defense industry, buyer is the Navy and Coast Guard) and consumer-funded boat building (a discretionary durable, buyer is households). One is supply-constrained and pointing up on funded backlog — the two U.S.-listed primes alone booked roughly $26 billion of ship revenue in 2025 [1][2]. The other is demand-cyclical and in its third year of working off a pandemic boom — 2025 new powerboat retail units fell 8.8% to 215,237 [3]. That contrast is the whole story, and it lives one level down.

2. What's inside — and why 3366 equals 33661

The group has a single child, so the map is trivial:

Everything investable, every economic driver, and every number sits inside 33661 and its two national industries. The one shape worth carrying up: the two halves are lopsided in opposite directions — ship building is about 64% of the code's receipts but only about 35% of its establishments, while boat building is about 36% of receipts spread across roughly 65% of establishments [4][5]. Few large government-work yards on one side, many small consumer factories on the other. This page does not re-derive the rest — see the 33661 primer for the ship-vs-boat split, the company rosters, and the mechanics.

3. How big it is (this level's rollup)

Federal figures for NAICS 3366, from our ground-truth file for this level. Because 3366 has one child, these are also the 33661 totals:

So the group is a roughly $47 billion, 150,000-worker manufacturing sector. The market-concentration HHI (Herfindahl-Hirschman Index, a standard concentration measure) that Census computes for this level is suppressed, so we report no value — but the ratios above are a blend, and that is the point at this level. The group's CR4 of 45.7% sits between ship building's 68.5% and boat building's 26.7%, and its CR8 of 53.5% between 76.1% and 40.8%; boat building's published HHI of 278.8 is squarely unconcentrated [4]. The blended number is not a description of any real market — it is a protected oligopoly at the ship end and near-perfect competition at the boat end, averaged (CR4 = the combined revenue share of the four largest firms).

Undercount caveat. These are private-sector statistics. The biggest omission is on the ship side: the four government-owned "public" naval shipyards (Norfolk, Portsmouth, Puget Sound, Pearl Harbor), which do the Navy's in-house nuclear submarine and carrier maintenance, are not counted — on the order of 37,000 federal civilian workers, so true national ship-and-boat-building employment is well above the ~150,000 private figure, closer to ~185,000 [6][7]. There is little tiny-operator undercount; small boat and repair shops are captured reasonably well. Separately (a scope point, not an undercount): the boat-building line is factory shipments only — engines, trailers, dealers, service, and used boats sit in adjacent codes, which is why the trade group NMMA (National Marine Manufacturers Association) measures 2024 U.S. recreational-marine retail spending at $55.6 billion and the wider "boating economy" at roughly $230 billion [8]. The ship side has the same trap in the other direction, where "shipbuilding economic impact" studies fold in suppliers and induced jobs. Neither is NAICS revenue.

4. The investable universe — where value concentrates

Value is lopsided toward the ship half by dollars, toward the boat half by the number of clean public ways in — though that second advantage narrowed in 2026 (full rosters in the 33661 primer). On the ship side, most revenue in the code flows through two U.S.-listed defense contractors — General Dynamics (Marine Systems: Electric Boat, Bath Iron Works, NASSCO, ~$16.7 billion of 2025 revenue) [1] and Huntington Ingalls Industries (Newport News, Ingalls, ~$9.6 billion of 2025 shipbuilding revenue) [2] — with an increasingly foreign-owned mid-tier and a large, un-investable block of public naval-yard capacity [6]. The field is genuinely tiny: GAO counts only seven builders of Navy battle-force ships in the entire country [9]. On the boat side, a niche consumer sector still offers an unusually deep set of listed choices — a diversified builder-plus-propulsion giant, two focused pure-play boat builders, an RV-plus-marine diversifier, and two public retailers — but that roster shrank in May 2026, when MasterCraft acquired Marine Products, removing MPX as standalone public exposure [10]. Several of the highest-volume builders remain private.

5. How the money works

Two opposite financial engines, held under one code. The ship half is long-cycle government contracting: owners earn from multi-year Navy contracts, revenue is booked over time against an estimate of total cost — a rising estimate triggers an immediate profit charge, and HII recorded $350 million of gross unfavorable cumulative catch-up adjustments in 2025 [2] — margins are thin (Newport News 5.1%, Ingalls 7.6%, GD Marine Systems 7.0% in 2025) [1][2], and profit turns on throughput: ships delivered per year, gated by skilled labor. The boat half is cyclical durable-goods manufacturing: revenue is units × price × mix sold wholesale to dealers, with high operating leverage on a largely fixed cost base, and it is doubly rate-sensitive — higher interest rates hit both the consumer's boat loan and the dealer's floor-plan financing, which advances roughly 70–85% of inventory value at prime plus a spread [12]. Neither half competes on open-market price the way most manufacturers do.

One thing only this level can see. Right now the "thin-margin" defense business is out-earning the consumer one: Brunswick's Boat segment ran a 2.1% GAAP operating margin in 2025, down from 4.1% [11] — below Newport News' 5.1% and less than a third of GD Marine Systems' 7.0% [1][2]. The familiar framing (steady low-margin government work versus juicy consumer manufacturing) inverts at a trough, because fixed-price defense risk is chronic and bounded while consumer operating leverage is acute and unbounded. Any comparison of the two halves' profitability has to say where in the cycle it is standing.

6. What drives demand

The two demand engines are essentially uncorrelated. Ship demand is driven by the Navy budget (a 30-year plan targeting 381 manned ships at roughly $40 billion a year, more than $1 trillion across 30 years, which CBO put at 46% above the preceding five-year average appropriation) [13], the China buildup and the AUKUS (Australia–UK–US) submarine partnership, and an unmet fleet-maintenance backlog severe enough that 18 of 49 attack submarines could not deploy because the yards could not fix them [7]. Demand is not the constraint, capacity is — GAO estimates the industrial base needs 174,000 new workers over a decade [9]. Boat demand is driven by consumer confidence, household wealth, and interest rates, plus the trade-up and used-boat substitution cycle and demographics; NMMA attributed 2025's 8.8% unit decline to elevated rates, inflation, and subdued confidence [3]. Here demand is the swing variable. A recession that guts boat sales barely touches a submarine program, which is exactly why the code is a portfolio of opposites rather than a single cycle.

7. Regulation

Regulation creates the ship market and constrains the boat market — with one real point of symmetry. The Jones Act (Merchant Marine Act of 1920) requires cargo moving between U.S. ports to travel on U.S.-built, -owned, -flagged, and -crewed ships, which keeps domestic commercial shipbuilding alive [14]. Defense acquisition rules, export controls, and CFIUS (Committee on Foreign Investment in the United States) review gate the ship side and its foreign-ownership wave. The symmetry is environmental: both children are regulated hazardous-air-pollutant sources under NESHAP — a surface-coating standard for shipbuilding and ship repair, a styrene-and-resin standard for boat manufacturing — alongside EPA (Environmental Protection Agency) marine-engine emissions rules and USCG (U.S. Coast Guard) recreational-boat safety standards [15]. Policy is also proving volatile: USTR Section 301 port-entry fees on China-built and China-linked ships phased in from October 14, 2025 and were suspended for one year on November 10, 2025 [16]. A 2025–26 stimulus cluster (Executive Order 14269 and the proposed SHIPS for America Act, with a 25% shipyard investment tax credit) leans toward the ship half — proposals and directives, not yet fully funded law [17]. Details are in the 33661 primer.

8. Consolidation

Same code, opposite consolidation logics — and opposite triggers. The ship half concentrates because the work is too hard and capital-heavy to spread: a protected duopoly at the top (sole nuclear-carrier builder; two teaming submarine builders) and a mid-tier being rolled up by allied foreign owners, with near-impossible greenfield entry. But here the customer decides who survives, not the market — the Navy canceled the Constellation-class frigate in late 2025 and then split a new Landing Ship Medium program between Bollinger and Marinette in 2026 [18]. The boat half concentrates because scale in brands and distribution beats a long tail of single-brand builders — brand portfolios, dealer roll-ups, and volume scale in value segments — even though the national CR4 of 26.7% at the boat industry looks fragmented [4]. In 2026 that consolidation reached the listed names themselves, with MasterCraft's acquisition of Marine Products combining ski/wake, pontoon, sterndrive, and saltwater-fishing brands under one public company [10]. Ship consolidation follows the budget; boat consolidation follows the cycle.

9. Risks

Ship half: single-customer/political risk (budget fights, program cancellations — Constellation is the live example [18]), fixed-price and inflation losses booked immediately through estimate revisions [2], labor as the hard ceiling on throughput, and a structural commercial cost disadvantage. Boat half: cyclicality above all, double interest-rate sensitivity [12], channel-inventory whipsaw, input-cost and tariff inflation, and secular participation questions. Shared: skilled-trades scarcity and steel/aluminum/resin input inflation hit both — but the risks that matter most to each child (defense-budget risk vs. consumer-recession risk) are largely independent, so a position spanning the code is less correlated than it looks. The one place they may not be independent is labor: both halves draw on the same welders, pipefitters, and electricians, and boat-building payrolls fell from 44,800 (April 2024) to 40,900 (preliminary March 2025) while ship-building-and-repair employment held roughly flat at 104,700 (November 2025) against 107,000 (December 2024) [19] — exactly as the ship half was told it needs 174,000 additional workers [9]. Whether that is a labor transfer or two separate shortages is an open question, not a settled fact.

10. How to invest and the outlook

Because 3366 is identical to 33661, there is nothing to buy "at the group level" — you invest in the two halves below. Ship is bought as a backlog-execution, thin-margin defense-growth story (the two listed primes, foreign-listed mid-tier parents, or aerospace-and-defense ETFs — exchange-traded funds — that hold them); record backlog is not the same as attractive margins, and a larger Navy budget does not automatically produce more delivered ships. Boat is bought as a consumer cyclical (a diversified builder, the two remaining higher-beta pure plays, an RV-plus-marine wrapper, or the two retailers), where the multiple you pay across the cycle matters more than the headline yield — confirm current valuations before buying, and note that Marine Products is no longer a standalone route [10]. Private routes run through repair/specialty yards and the allied-capital wave on the ship side, and niche builders, dealer roll-ups, floor-plan private credit, and marina real assets on the boat side.

Outlook. The two halves are on different clocks but, unusually, on the same margin story. Ship building has demand it can't fully meet (funded backlog plus policy tailwinds [17], gated by labor and yard capacity [9]), and boat building has capacity it can't fully use (a third year of post-boom normalization, units down 8.8% in 2025 and hinging on rates and confidence [3]) — so both are currently margin-recovery cases, one recovering from contract estimates and the other from volume. Read 3366 not as one industry but as a paired trade: a supply-constrained defense grower and a demand-cyclical consumer manufacturer, sharing a labor pool and a made-in-America footprint but almost nothing on the demand side. For the full company-by-company detail, see the 33661 primer.

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Sources

1. General Dynamics, 2025 Form 10-K (Marine Systems revenue ~$16.7B, 7.0% margin, contract value; Electric Boat, Bath Iron Works, NASSCO). https://www.sec.gov/Archives/edgar/data/40533/000004053326000006/gd-20251231.htm
2. Huntington Ingalls Industries, 2025 Form 10-K (~$9.6B shipbuilding revenue, backlog, Newport News 5.1% / Ingalls 7.6% margins, $350M cumulative catch-up adjustments). https://www.sec.gov/Archives/edgar/data/1501585/000150158526000006/hii-20251231.htm
3. National Marine Manufacturers Association, "2025 New Boat Retail Sales," 2026 (215,237 units, −8.8%; cautious demand environment). https://www.nmma.org/press/article/25432
4. U.S. Census Bureau, 2022 Economic Census — Concentration Ratios and Statistics (NAICS 3366/33661 and children: receipts, firms, CR4/CR8/CR20/CR50; level HHI suppressed; 336612 HHI 278.8). https://www.census.gov/programs-surveys/economic-census.html
5. U.S. Census Bureau, County Business Patterns 2023 (NAICS 3366/33661 and children: establishments, employment, annual and Q1 payroll). https://www.census.gov/programs-surveys/cbp.html
6. USNI News, "Navy Plans to Spend $21B Over 20 Years to Optimize, Modernize Public Shipyards," 2018; Naval Sea Systems Command, "Shipyards — About Us" (four government-owned public naval shipyards). https://news.usni.org/2018/04/17/navy-plans-spend-21b-20-years-optimize-modernize-public-shipyards; https://www.navsea.navy.mil/Home/Shipyards/About-Us/
7. 19FortyFive, "37 Percent of US Navy Nuclear Attack Submarines Can't Deploy Because the Yards Can't Fix Them," 2026 (18 of 49 attack submarines; ~37,000 public-shipyard federal civilian workers). https://www.19fortyfive.com/2026/07/37-percent-of-us-navy-nuclear-attack-submarines-cant-deploy-because-the-yards-cant-fix-them/
8. National Marine Manufacturers Association, "2024 Industry Sales by Category and State Report: Total Spending $55.6B," 2025; "Recreational Boating's Economic Impact Soars to $230 Billion," 2024. https://www.nmma.org/press/article/25236; https://www.nmma.org/press/article/24334
9. U.S. Government Accountability Office, Navy Shipbuilding: Challenges Impacting Shipbuilders' Ability to Meet the Navy's Goals, GAO-25-106286 (seven battle-force builders; 174,000 additional workers needed over a decade). https://files.gao.gov/reports/GAO-25-106286/index.html
10. MasterCraft Boat Holdings, Form 10-K FY2025 and Form 8-K (Marine Products acquisition completed May 15, 2026). https://www.sec.gov/Archives/edgar/data/1638290/000095017025111682/mcft-20250630.htm; https://www.sec.gov/Archives/edgar/data/1638290/000119312526226778/d123539d8k.htm
11. Brunswick Corporation, Form 10-K FY2025 (Boat segment 2.1% GAAP operating margin vs. 4.1% in 2024). https://www.sec.gov/Archives/edgar/data/14930/000001493026000027/bcorp-20251231.htm
12. Crestmont Capital, "Floor Plan Financing: The Complete Guide," 2026 (70–85% advance rates; prime plus spread); National Marine Manufacturers Association, "Dealer Floor Plan Financing FAQ." https://www.crestmontcapital.com/blog/floor-plan-financing; https://www.nmma.org/assets/cabinets/Cabinet214/dfp_faqs.pdf
13. Congressional Budget Office, "An Analysis of the Navy's 2025 Shipbuilding Plan," 2025 (~$40B/yr, >$1 trillion over 30 years, 381 manned ships); "An Analysis of the Navy's Fiscal Year 2025 Shipbuilding Plan," 2024 (46% above preceding five-year average appropriation). https://www.cbo.gov/publication/61155; https://www.cbo.gov/publication/60732
14. Cato Institute, "New Data Lay Bare the Jones Act's Broken Shipbuilding Bargain," 2025 (Merchant Marine Act of 1920 build-domestic requirement). https://www.cato.org/blog/new-data-lays-bare-jones-acts-broken-shipbuilding-bargain
15. U.S. Environmental Protection Agency, Shipbuilding and Ship Repair (Surface Coating) NESHAP; Boat Manufacturing NESHAP; "Regulations for Emissions from Marine Spark-Ignition Engines"; U.S. Coast Guard recreational-boat construction and safety standards. https://www.epa.gov/stationary-sources-air-pollution/shipbuilding-and-ship-repair-surface-coating-national-emission; https://www.epa.gov/stationary-sources-air-pollution/boat-manufacturing-national-emission-standards-hazardous-air; https://www.epa.gov/regulations-emissions-vehicles-and-engines/regulations-emissions-marine-spark-ignition-engines
16. White & Case, "USTR issues final Section 301 actions in China shipbuilding investigation," 2025 (port fees from October 14, 2025); Holland & Knight, "USTR Port Fee Suspension: What You Need to Know," 2025 (one-year suspension from November 10, 2025). https://www.whitecase.com/insight-alert/ustr-issues-final-section-301-actions-china-shipbuilding-investigation; https://www.hklaw.com/en/insights/publications/2025/11/ustr-port-fee-suspension-what-you-need-to-know
17. King & Spalding, Executive Order 14269 "Restoring America's Maritime Dominance," 2025; S.1541 — SHIPS for America Act of 2025 and Office of Senator Mark Kelly section-by-section (25% shipyard investment tax credit). https://www.kslaw.com/news-and-insights/executive-order-restoring-americas-maritime-dominance-revitalizing-the-us-shipbuilding-and-maritime-industry; https://www.congress.gov/bill/119th-congress/senate-bill/1541/text; https://www.kelly.senate.gov/wp-content/uploads/2025/04/SHIPS-for-America-Act_Section-by-Section_4.30.2025.pdf
18. Daily Press, "More details on Navy's decision to cancel Marinette contract," 2025 (Constellation-class frigate cancellation); USNI News, "Bollinger, Fincantieri Marinette Marine to Build Landing Ship Medium, Navy Says," 2026. https://www.dailypress.net/news/local-news/2025/12/more-details-on-navys-decision-to-cancel-marinette-contract/; https://news.usni.org/2026/02/18/bollinger-fincantieri-marinette-marine-to-build-landing-ship-medium-navy-says
19. U.S. Bureau of Labor Statistics, Current Employment Statistics (ship building and repairing, December 2025 table; boat building, April 2025 table). https://www.bls.gov/ces/data/employment-and-earnings/2025/table1a_202512.htm; https://www.bls.gov/ces/data/employment-and-earnings/2025/table1b_202504.htm