Boat Depreciation Life: MACRS Classes, ADS, and Section 179

A boat used in a trade or business has a depreciation life of either 7 or 10 years under the IRS’s General Depreciation System. The 10-year class covers vessels, barges, tugs, and similar water transportation equipment that moves cargo or passengers. Everything else that qualifies as a depreciable working boat (most commercial fishing vessels, dive charter boats, and similar craft with no assigned class life) defaults to the 7-year class. If you’re forced onto the Alternative Depreciation System, those periods stretch to 12 years and 18 years, respectively.

7-Year vs 10-Year: How to Tell Which Class Your Boat Falls Into

The distinction hinges on function. The 10-year MACRS class is specifically for water transportation equipment — the working fleet that moves things or people from one point to another. Towboats, crew boats, passenger ferries, tugs, and barges all sit here.¹

A boat that doesn’t fit that description and isn’t assigned to any other specific asset class falls into the catch-all 7-year category for property with no designated class life.¹ A lobster boat hauling traps isn’t transporting cargo between points, so it typically has no assigned class life and lands at 7 years. Same for most sport-fishing charter boats and dive boats. If you’re uncertain, Table B-2 in Publication 946 lists the specific asset classes; anything not listed there defaults to 7 years.

Under GDS, the default calculation method is 200% declining balance, which front-loads the deduction in the early years of the recovery period and then switches to straight-line once that produces a larger deduction. You can elect straight-line over the same GDS recovery period if you’d rather spread the deduction evenly.¹

The First-Year Convention Can Shrink Your Deduction

MACRS never lets you claim a full year of depreciation in the year of purchase. The default is the half-year convention: half a year in the year the boat is placed in service, half a year in the final recovery year, regardless of the actual purchase month.

Watch for the mid-quarter trap. If more than 40% of the total depreciable basis of all property you place in service that year falls in the last three months, the half-year convention is replaced by the mid-quarter convention for everything placed in service that year.² A boat that’s your only major purchase, bought in November, will almost certainly trigger this rule and pick up only about half a month of first-year depreciation instead of six months.

When You’re Forced Onto ADS (12 or 18 Years)

The Alternative Depreciation System uses the straight-line method over a longer life. For a boat that sits in the 7-year GDS class, the ADS period is 12 years. For 10-year water transportation equipment, it’s 18 years based on the class life assigned under Revenue Procedure 87-56.¹

ADS becomes mandatory the moment qualified business use drops to 50% or below in any year of the recovery period. You can also elect ADS voluntarily to smooth out deductions or manage alternative minimum tax exposure, but the election is irrevocable for that property.

The Threshold Question: Does Your Boat Qualify at All?

A boat qualifies for depreciation when you own it, use it in a business or income-producing activity, and expect it to last more than a year. The IRS treats property as “placed in service” on the date it’s ready and available for its intended business use, whether or not you actually use it that day.¹ A charter boat rigged and available for bookings at the marina is placed in service even if the phone hasn’t rung yet.

Boats are “listed property,” so the bar is higher than for ordinary business equipment. More than 50% of the boat’s total annual use has to be for a qualified business purpose: commercial fishing, chartering, marine research, or similar trade-or-business activity.¹ Investment use counts toward the depreciation calculation but does not count toward the 50% test.

Entertaining clients on the boat isn’t going to help. The Tax Cuts and Jobs Act eliminated the deduction for entertainment facilities (explicitly including yachts) after December 31, 2017, so hosting clients aboard generates no business deduction and adds nothing toward the 50% threshold.³ A boat used strictly for personal recreation can’t be depreciated at all. Mixed use is depreciated at the business-use percentage, but you still have to clear the over-50% qualified-business-use bar to reach the faster methods.

What Happens if Business Use Slips Below 50%

Listed property rules under IRC Section 280F require qualified business use to exceed 50% every year of the recovery period, not just the first year.¹ If it drops to 50% or below in any later year, two things happen at once.

First, you must switch to straight-line depreciation over the ADS recovery period (12 or 18 years) for that year and every remaining year of the boat’s life.

Second, you owe tax on “excess depreciation”: the difference between what you claimed using accelerated methods in prior years and what straight-line ADS would have allowed over the same period. That excess is added back to your income for the year business use dropped and reported on Form 4797 as ordinary income.⁴ A charter operator who takes a year off and uses the boat personally doesn’t just lose that year’s deduction. They pay back a chunk of prior years’ deductions on top.

Deducting the Boat Faster Than the Recovery Period

The 7 or 10-year life is the default schedule. Two provisions can compress most or all of the deduction into year one, provided the boat clears the over-50% business use test.

Section 179 Expensing

Section 179 lets you deduct the full cost of qualifying business property in the year it’s placed in service, up to an annual cap. For tax years beginning in 2025, the maximum Section 179 deduction is $2,500,000, phasing out dollar-for-dollar once total qualifying property placed in service exceeds $4,000,000.⁵ The deduction can’t exceed your taxable business income for the year; anything above that carries forward.

Section 179 tracks business use. If the boat is used 75% for business, you can apply Section 179 to 75% of the cost. If business use later drops to 50% or below, the Section 179 amount gets recaptured along with any other excess depreciation.

Bonus Depreciation

Bonus depreciation allows a first-year write-off of a qualifying asset’s cost. The One, Big, Beautiful Bill signed in 2025 restored the 100% rate for qualified property acquired after January 19, 2025, making it fully available for boats placed in service in 2026.⁶ Qualified property includes any MACRS property with a recovery period of 20 years or less, which covers both 7-year and 10-year boats.⁷

The same listed-property snare applies. If business use falls to 50% or below, the boat no longer qualifies for bonus, and any bonus deduction previously claimed is subject to recapture. Many operators use Section 179 first (it has a carry-forward and more control) and apply bonus to whatever eligible basis remains.

Records the IRS Requires

Because boats are listed property, inadequate records can wipe out the depreciation deduction entirely.¹ The records have to be contemporaneous: kept at or near the time of each use. A logbook stitched together at year-end from memory tends to collapse under audit.

Every outing should capture:

The date the boat was used.
The specific business purpose (“charter trip for Smith party,” “commercial fishing run, Georges Bank”).
Duration or distance. The IRS suggests allocating use based on mileage for transportation property.
Expenses tied to that trip, including fuel, maintenance, and dock fees.

Personal use goes in the log with the same detail. Business-use percentage is calculated from total use, so any unaccounted time reads as personal and drags the ratio down. A bound logbook kept aboard, filled in at the end of each trip, meets the contemporaneous standard without much fuss.

Liveaboards and Rental Dwellings

The 7 and 10-year figures assume the boat is being used as working equipment. If you rent the boat out as a liveaboard or houseboat and it functions as a dwelling unit, the recovery period jumps to 27.5 years as residential rental property.¹ The vacation-home rules under Section 280A can also limit deductions if you personally use it for more than 14 days or 10% of the days it’s rented, whichever is greater.

A boat with a berth, galley, and head can qualify as a second home for the mortgage interest deduction, but that position generally can’t be stacked with depreciating the same boat as a business asset for the same use periods. The IRS treats those as incompatible.

1
Internal Revenue Service. Publication 946 (2025), How To Depreciate Property
2
eCFR. 26 CFR 1.168(d)-1 – Applicable Conventions, Half-Year and Mid-Quarter Conventions
3
Office of the Law Revision Counsel. 26 U.S. Code 274 – Disallowance of Certain Entertainment, Etc., Expenses
4
Internal Revenue Service. Publication 463 (2025), Travel, Gift, and Car Expenses
5
Internal Revenue Service. Instructions for Form 4562 (2025)
6
Internal Revenue Service. One, Big, Beautiful Bill Provisions
7
Office of the Law Revision Counsel. 26 U.S. Code 168 – Accelerated Cost Recovery System