Methodology & sources
Every figure on this site, where it came from, how much to trust it, and when we last checked. If a number here is wrong, that's a bug — report it and we fix it.
The rules we follow
- Exact where exact exists. CRT licence fees are published prices, so we treat them as facts: our licence figures are verified against the official CRT licence calculator (July 2026) and re-verified every April when new rates take effect.
- Ranges where reality is a range. Moorings, heating, insurance and maintenance genuinely vary by region, boat and habits. We publish low–high ranges with the assumptions stated, and we label how confident we are in each.
- Dated, always. Every figure carries a last-verified date. Undated cost content is how this niche ended up full of 2019 licence fees.
- Corrected by boaters. When someone who actually pays a bill tells us our range is off — with a real price and a location — we verify and update. That feedback loop is the product.
The source register
Last full verification pass: 5 July 2026.
CRT licence fees
High — official/verified2026/27 base prices by length band (e.g. 54–57ft narrowbeam with home mooring: £1,404.46/yr)
Source: Verified against the official CRT licence calculator, July 2026; 4.85% rise confirmed by CRT press release, 12 Nov 2025 · verified 2 July 2026
CRT licence surcharges
High — official/verifiedNo home mooring +15%; beam 2.17–3.24m +19%; beam over 3.24m +38% (2026/27). Phasing to +25%/+25%/+50% by April 2028
Source: CRT: “New structure of boat licence pricing”, plus verification against the official CRT calculator · verified 2 July 2026
Licence discounts
High — official/verifiedElectric propulsion −25%; historic boat −10%
Source: Verified against the official CRT licence calculator, July 2026 · verified 2 July 2026
Boat Safety Scheme
High — official/verifiedCertification fee £97.20 from 1 April 2026; typical all-in examination £230–£320, every 4 years
Source: Boat Safety Scheme official fees page; examiner price lists · verified 2 July 2026
⚠ Examiner labour varies by region — get local quotes.
Mooring — marina
Low — genuinely variable, widest rangesLeisure ~£45–£70/ft/yr; residential ~£75–£110/ft/yr (Midlands/North baseline)
Source: 2026 market guides (JD Narrowboats mooring costs; narrowboats.uk) and marina price lists · verified 2 July 2026
⚠ The most regional figure on this site: London & the South East can be 2–3× higher. Tell us your real mooring cost and we'll refine these ranges.
Mooring — CRT online (towpath)
Low — genuinely variable, widest ranges~£1,500–£4,500/yr for a typical narrowboat, by region and facilities
Source: CRT Waterside Moorings guide prices; 2026 market guides · verified 2 July 2026
⚠ Set by auction/fixed-price listings; varies widely by location.
Insurance
Medium — corroborated market figuresComprehensive £250–£600/yr for a typical narrowboat; liveaboard +10–20%
Source: Market indications from UK narrowboat insurers (Craftinsure, GJW, Topsail) and 2026 market guides · verified 2 July 2026
⚠ Indicative market ranges, not quotes — boat value is the biggest factor.
Solid fuel
Medium — corroborated market figures25kg smokeless briquettes ~£13–£20/bag canalside; typical liveaboard use 1–2.5 bags/week over an 18–24 week season
Source: livingonanarrowboat.co.uk stove fuel test (14 bags/6 weeks in a cold snap); general liveaboard guidance; corrected downward 4 July 2026 after a boater reported our first estimate (1.5–3 bags/week) ran high · verified 4 July 2026
⚠ Usage varies with insulation, stove efficiency and how cold the winter is.
Diesel
Medium — corroborated market figuresCanalside diesel ~£1.10–£1.50/L domestic rate, ~£1.30–£1.70/L propulsion rate (2026); typical burn 1–1.5 L/engine-hour
Source: Canalside price boards and marina price lists, mid-2026 · verified 2 July 2026
⚠ Prices move with the oil market; the 60/40 propulsion/domestic split declaration affects the duty you pay.
Gas
Medium — corroborated market figures13kg propane ~£40–£50/bottle (2026); liveaboard cooking-only use ~2 bottles/yr (more if hot water is also gas-heated); leisure use ~1–4 bottles/yr
Source: Canalside chandler and marina price lists; boater-reported usage (2 bottles/yr cooking-only vs ~1 bottle/week on gas central heating; a leisure cruiser reporting lower use than our first estimate) — corrected downward twice, 4 July 2026, after our first estimates (6–10 bottles/yr liveaboard, 2–4 leisure) were reported too high · verified 4 July 2026
Hull blacking
Medium — corroborated market figures£13–£18/ft including dock, every 2–3 years
Source: 2026 yard price lists (e.g. Braunston Boats, holding 2025 prices at £13–£14.75/ft + VAT) · verified 2 July 2026
Engine service
Medium — corroborated market figures£150–£300/yr for a standard yard service, less if DIY
Source: Corroborated by multiple independent 2026 guides quoting £200–£300 for professional marine engine servicing · verified 4 July 2026
⚠ A boater reported paying £700 for their annual service — likely a fuller service including parts, not the norm we've found elsewhere, but worth knowing yards vary a lot.
Toilet, pump-out & consumables
Medium — corroborated market figuresPump-out £12–£20 a time (~17–26/yr liveaboard, ~6–12/yr leisure) plus tank sanitiser → ~£90–£560/yr; cassette toilets use free/near-free Elsan points, cost is chemical only ~£20–£110/yr; composting toilets ~£30–£70/yr for soak medium (coco-coir brick ~£1.50–£3, lasting ~1–2 weeks) plus optional liner bags; diesel-bug fuel treatment ~£10/yr on top for any boat that burns diesel
Source: Marina/chandler pump-out price boards; toilet-chemical and coco-coir/soak-medium retail pricing; diesel-bug additive product pricing — modelled as its own calculator line, driven by toilet type, from 8 July 2026 (previously listed only as an excluded cost) · verified 8 July 2026
⚠ The cost that depends most on your setup: the calculator asks which toilet system you have and models each. Pump-out frequency and composting soak-medium use are usage assumptions, and composting setups vary a lot (coir vs peat, liners or not) — tell us your real numbers and we'll refine them.
Maintenance contingency
Low — genuinely variable, widest ranges£250–£550/yr leisure; £350–£750/yr liveaboard
Source: Independent guidance citing a ~£150/yr baseline contingency and one liveaboard couple's actual 2024/25 spend of £514 — corrected downward 4 July 2026 after our first estimate (£500–£1,000 liveaboard) was reported too high · verified 4 July 2026
⚠ A judgement figure by nature; an older boat or a bad year can still exceed it.
Electric propulsion — consumption & savings
Medium — corroborated market figures~1.0–1.5 kWh per cruising hour; fuel-cost saving over £500/yr and up to 70% vs a comparable diesel boat burning 250L/yr
Source: Inland Waterways Association Sustainable Boating Group, "An Introduction to Electric Narrowboating" (March 2024) — written by an electric-narrowboat owner, the closest thing to an authoritative primary source in this niche · verified 5 July 2026
⚠ The IWA guide itself says the technology is still evolving and its own recommendations may date quickly.
Hybrid propulsion — fuel saving
Low — genuinely variable, widest rangesModelled at 40–70% of the equivalent diesel-only fuel cost
Source: Marine-hybrid and Canal World forum descriptions of parallel-hybrid savings (eliminated lock-idling, stored charge covering 1–2 hours per hour of engine charging) — no clean industry-standard percentage found, unlike the pure-electric figures above · verified 5 July 2026
⚠ Meaningfully less well-sourced than the electric figures — a parallel hybrid retains a diesel engine, and real-world saving depends heavily on how it's driven. Tell us your real numbers.
Charging costs
Medium — corroborated market figuresShore power ~22p/kWh; generator ~40p/kWh; solar-mixed blended ~15–30p/kWh
Source: IWA electric narrowboating guide (shore/generator rates); general solar payback guidance · verified 5 July 2026
Battery bank — lithium (LiFePO4)
Medium — corroborated market figures~£250–£350 per usable kWh; lifespan 8–15 years
Source: Marine and home-battery-storage retail pricing (multiple 2026 sources); IWA guide on usable-capacity sizing · verified 5 July 2026
⚠ Triangulated from general marine/home-storage retail pricing, not narrowboat-specific chandlery quotes — same confidence tier as insurance and mooring elsewhere on this site. Lithium prices are trending down, so this is due a re-check every 6 months, not just annually.
Battery bank — lead-acid/lead-carbon
Low — genuinely variable, widest ranges~£125–£200 per usable kWh (roughly half lithium's cost for comparable usable capacity); lifespan widened to 3–5 years
Source: IWA guide ("lithium... at least double" lead-acid's cost for comparable usable capacity, since lead-acid needs a bigger rated bank); general marine battery guidance (2–3 years under frequent deep cycling) · verified 5 July 2026
⚠ The 3–5 year lifespan is our own judgement widening beyond the 2–3 years generally cited for marine batteries, reasoning that narrowboat traction cells are more robust than generic leisure batteries under lighter cycling. This is exactly the kind of assumption we'd expect a boater to correct — please do if it's off for you.
What the calculator deliberately leaves out
These are real costs we exclude from the headline totals — either because they only apply to some boaters or because bundling them in would hide them. The guides discuss each one:
- Council tax on residential moorings (usually Band A, ~£1,300–£1,600/yr)
- Marina electricity (metered, typically £300–£900/yr for liveaboards)
- Gold Licence for Environment Agency rivers (Thames, Nene, Great Ouse)
- Paid winter moorings for continuous cruisers (~£600–£1,200 for Nov–Mar)
- Broadband/connectivity and TV licence
- Capital cost, depreciation and survey costs of buying the boat itself
- The capital cost of converting to or buying electric/hybrid propulsion itself (£10,000–£40,000+ for a retrofit; £250,000+ for a bespoke new-build from specialist builders) — this calculator only models the ongoing running costs, not the upfront cost of going electric.
Update cadence
CRT announces new licence fees each autumn, effective 1 April. We re-verify the full licence table against official CRT prices every April (and when any in-year change is announced), and re-check the market-based ranges at the same time. Licensing reform following the 2025 Commission is in progress — the licence guide tracks it.
Changelog
- 8 July 2026: two fixes from the r/canalboats launch feedback. Lowered the running-cost calculator’s minimum boat length from 30ft to 20ft — plenty of narrowboats are shorter than 30ft, and the licence bands and per-foot costs already scale at those lengths. And promoted toilet running costs from the excluded-costs list to a proper calculator line — “Toilet & consumables” — with a new toilet-type selector (pump-out, cassette or composting), since a boater rightly pointed out these are real recurring costs. Pump-out, tank sanitiser (“blue”) and diesel-bug fuel treatment are all covered; see the source register above for the figures and how much they depend on which system you have.
- 5 July 2026: added an electric and hybrid propulsion cost model after boaters requested it at launch — new "Propulsion" and "Battery bank (amortised)" categories, adjustable battery chemistry/size/replacement-interval sliders in the calculator, CRT's electric licence discount applied automatically, and a new electric/hybrid cost guide. Primary source: the Inland Waterways Association's "An Introduction to Electric Narrowboating" (2024). Hybrid fuel-saving and lead-acid battery lifespan figures are flagged lower confidence than the rest of the new model — see the source register above.
- 4 July 2026 (later): more Reddit feedback. Leisure gas usage was lowered again after a weekend cruiser reported using less than our estimate. Added pump-out, cassette and composting toilet running costs to the excluded-costs list below — a real, sourced cost we'd missed entirely, and one that depends on which toilet system you have rather than anything the calculator asks about. Added a caveat to the engine service figure after a boater reported paying £700 for a fuller annual service than the £150–300 we model (kept the range as-is since it's corroborated by multiple other sources, but the caveat is there so you know yards vary a lot).
- 4 July 2026: corrected three figures after boater feedback on Reddit. Solid fuel and gas usage assumptions were running high — revised down and re-sourced (see the source register above). Maintenance contingency was also revised down after independent evidence suggested our first estimate was too conservative. "Heating & fuel" was also split into separate Heating and Propulsion fuel lines, since bundling them made the combined figure hard to sanity-check against a real fuel bill.
- 2 July 2026: site launched with 2026/27 licence fees verified against the official CRT licence calculator; all running-cost ranges sourced as listed above.