Co-owning a boat: how to split the costs
Quick answer
Split the fixed costs by ownership share and the use-based costs by engine hours from the hour meter, then put a set amount aside each month for big repairs. In one illustration, three owners at 40, 30 and 30 percent pay $3,840, $2,880 and $2,880 of $9,600 in fixed costs, and 120 engine hours at $18 an hour is $2,160 of fuel.
Key points
- Fixed costs follow ownership share. Use-based costs follow engine hours read from the hour meter.
- Illustration: $9,600 of fixed costs a year at 40/30/30 is $3,840, $2,880 and $2,880.
- Illustration: 120 engine hours at $18 an hour is $2,160 of fuel. Logged as 60, 40 and 20 hours, the owners pay $1,080, $720 and $360.
- A monthly repair fund keeps an engine, sail or canvas bill from landing on one owner.
- Leaving arithmetic is boat value times share: a 30% share of a $40,000 boat is $12,000.
On this page
- Which boat costs follow ownership, and which follow use?
- How do you split the fixed costs by ownership share?
- How do you split fuel and engine use?
- How do you pay for big repairs?
- What does the year cost each owner?
- How do you schedule use, and what happens when someone leaves?
- How can EvenOut keep the numbers?
- Frequently asked questions
Which boat costs follow ownership, and which follow use?
Fixed costs follow ownership share, because they run whether or not anyone goes out. Use-based costs follow engine hours, because a trip burns fuel and wears the engine. As of October 2026, BoatUS lists insurance premiums, maintenance and repairs, fuel and storage, registration and taxes, and safety equipment as the ongoing costs of owning a boat.
| Cost type | Split by | Typical lines |
|---|---|---|
| Fixed | Ownership share | Slip or mooring, storage, insurance, registration, winterization or haul-out, safety equipment |
| Use-based | Engine hours from the hour meter | Fuel, oil and filter changes |
| Big repairs | Ownership share, paid into a monthly fund | Engine, sails, canvas |
Your boat may not have every line. A boat kept on a trailer has no slip, and a boat that stays in the water all year may skip the haul-out. List the lines you really have, then give each one a row in the table.
How do you split the fixed costs by ownership share?
Multiply each cost by each owner’s share. The numbers here are an illustration, not typical prices. Say three owners hold 40, 30 and 30 percent, and the year’s fixed costs are a slip at $4,200, insurance at $2,100, storage and haul-out at $2,300, and registration and other items at $1,000. That is $9,600.
- Owner A, 40 percent: $9,600 × 0.40 = $3,840.
- Owner B, 30 percent: $9,600 × 0.30 = $2,880.
- Owner C, 30 percent: $9,600 × 0.30 = $2,880.
The three amounts add back to $9,600. Monthly, $9,600 ÷ 12 is $800, so the owners pay $320, $240 and $240 a month, which also adds to $800.
How do you split fuel and engine use?
Read the hour meter before and after every trip and log the difference under the name of the owner who went out. The fuel cost per hour is the season’s fuel receipts divided by the hours on the meter, and each owner pays that rate times their own hours.
In the illustration, the meter moves 120 hours in the season and fuel works out to $18 an hour, so fuel costs $2,160. The owners log 60, 40 and 20 hours.
- 60 hours × $18 = $1,080.
- 40 hours × $18 = $720.
- 20 hours × $18 = $360.
The logged hours add to 120, which matches the meter, and the three amounts add to $2,160. If the meter shows more hours than the owners logged, share the unlogged hours by ownership share. Agree that rule before the season so a forgotten log does not fall on one person.
How do you pay for big repairs?
Set up a repair fund with a fixed monthly amount from each owner, split by ownership share. Pick the amount by estimating the next big job and dividing by the months until you need it. A $6,000 engine overhaul expected in 30 months is $200 a month, which at 40/30/30 is $80, $60 and $60.
Agree a spending limit as well, such as a repair over $500 needing every owner to say yes. The fund covers the engine, sails and canvas, and the fixed costs table above covers everything that recurs.
What does the year cost each owner?
Add the three parts for each owner. The repair fund is the monthly amount times 12: $80 is $960 a year, and $60 is $720.
| Owner | Fixed costs | Fuel | Repair fund | Year total |
|---|---|---|---|---|
| A, 40 percent, 60 hours | $3,840 | $1,080 | $960 | $5,880 |
| B, 30 percent, 40 hours | $2,880 | $720 | $720 | $4,320 |
| C, 30 percent, 20 hours | $2,880 | $360 | $720 | $3,960 |
The year totals add to $14,160, which is $9,600 fixed plus $2,160 fuel plus $2,400 in the repair fund. Owner A’s average is $490 a month, owner B’s is $360 and owner C’s is $330.
How do you schedule use, and what happens when someone leaves?
Share the season’s weekends by ownership share. In a season of 20 weekends, 40/30/30 owners get 8, 6 and 6 weekends. Rotate who picks first each month so the holiday weekends do not always go to the same person.
When an owner leaves, the arithmetic is the boat’s value times their share. If the owners value the boat at $40,000, a 30 percent share is $12,000. How that value is set, and what a change of owner means for the title and the insurance, are outside this page.
How can EvenOut keep the numbers?
Put the boat in a group and log each cost as you pay it. For a fixed cost, choose the Percent split and type 40, 30 and 30, and EvenOut shows “Adds up to 100%” when the three match. For fuel, choose Shares and use the hours as the shares: a $2,160 fuel total with 60, 40 and 20 shares comes to $1,080, $720 and $360. A cost that repeats, such as the slip fee, can be set to repeat monthly or yearly, and EvenOut adds it for you.
Owners who are not on EvenOut can be added with “Add a guest”. The group’s charts show the spending by category, person and month, and they are free. EvenOut records what each owner owes and does not move money, so each owner still pays through their own bank or app.
For a car shared the same way, see sharing a car with a friend. For a house, see co-owning a vacation home, which weights peak nights.
Frequently asked questions
What if the hour meter stops working?
Replace it and write down the last good reading and the new starting reading, so the hours stay continuous. For the gap, log each trip's length by hand and agree one set of estimates before anyone has a reason to argue about them.
What if a repair costs more than the fund holds?
Split the shortfall by ownership share, the same way the fund is split. Say the fund holds $2,000 and an engine repair costs $3,500. The $1,500 gap is $600 for the 40 percent owner and $450 each for the 30 percent owners. Raise the monthly amount afterward so the fund recovers.
What if owners hold unequal shares, such as 50/30/20?
The method is the same. On $4,800 of fixed costs, 50/30/20 gives $2,400, $1,440 and $960, and the three amounts add back to $4,800. Use the same shares for the repair fund so the split never has to be redone.
Do a guest's hours count?
Count them for the owner who brought the guest. The hour meter does not know who was on board, so charging guest hours to the host keeps the fuel split tied to who chose to go out.
Sources
Checked October 6, 2026.
Keep reading
- Guide Co-owning a vacation home: how to split the costs Split a shared vacation home: fixed costs by ownership share, cleaning and utilities by nights stayed, with peak nights weighted 1.5. Worked for 4 owners.
- Guide Sharing a car with a friend: how to split the costs Split fixed costs by ownership and running costs by miles. A $430 monthly fixed bill and $0.20 a mile gives $375 and $295 for 800 and 400 miles.
- Guide How to split a bill by percentage, with examples The formula for splitting a bill by percentage, with three worked splits of $1,250 (60/40, 50/30/20 and 33/33/34) and what to do when percents miss 100.
- Guide How to split expenses: five methods, one worked example One $480 cabin bill for four people, split five ways: equally, by percent, by shares, by exact amounts and by item. See the sums and pick the method.