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The engine is only part of the bill.
In 25-plus years of repowering boats out of Seattle, we've watched many owners budget for the engine and get surprised by everything else. Gears, exhaust, plumbing, controls, alignment, and yard time all end up on the same invoice, along with whatever other problems we find once the old engine comes out. A repower is the largest boat repair most owners ever face. This guide is for commercial operators and pleasure craft owners planning one (swapping the old engine for a new or remanufactured one) this off-season.
Typical Repower Cost Ranges
These planning ranges cover the engine, marine gear (the boat's transmission), installation, supporting systems, and sea trial (a test run on the water under load). Haul-out and yard fees are separate.
| Vessel type | Typical horsepower |
|---|---|
| Single-engine cruiser or small workboat | 100 to 300 hp |
| Trawler or cruiser, single engine | 300 to 500 hp |
| Yacht 40 ft and up, twin engines | 2 × 300 to 700 hp |
| Commercial fishing vessel or tug | 400 to 1,000+ hp |
Every boat is different, so we quote after we've seen the engine room. One example is the F/V Legacy, a Seattle fishing vessel we repowered. You can see the full F/V Legacy repower here.
What Drives the Price and What Pushes It Over Budget
The engine. Horsepower and brand move the price more than anything else. A factory remanufactured engine (a used engine rebuilt to factory spec and sold with a warranty) usually costs less than a new engine. New gets you the best fuel efficiency and the longest service life. If the trouble turns out to be a worn turbo, read up on whether to rebuild a turbocharger or replace it before committing to a full repower.
Labor. This covers pulling the old engine, installing the new one, aligning it to the prop shaft, plumbing and wiring it in, and a sea trial. Access is the wild card. An engine that lifts out through a hatch costs far less to swap than one that comes out through a cut in the cabin sole.
Supporting systems. The marine gear has to handle the new engine's torque, and old gear behind a new engine is a common source of trouble. Exhaust, fuel lines, filters, heat exchangers, and raw water pumps may all need replacing. If you're upgrading to a newer electronically controlled engine, you'll also need new harnesses and displays.
Surprises. Most of them hide under the engine you're removing. A different footprint may mean modifying the engine beds (the structural mounts the engine sits on). The new power curve may call for a different prop or gear ratio. Worn shafts, cutless bearings (the rubber-lined bearing that supports the prop shaft), and corrosion often show up only once there's room to see them. Build a contingency into the budget for exactly this reason. Commercial vessels also need an engine that meets current EPA marine emissions rules, which can narrow the choices.
Haul-out and yard time. Many repowers need a short haul-out (lifting the boat out of the water) for shaft, strut, or prop work. Yard fees run by the day, and Seattle yards book up in winter.
Why Off-Season Is the Time to Repower
The best time to repower is when you weren't going to use the boat anyway. Fishing boats keep their Alaska season, and pleasure boaters keep their summer weekends.
Lead times are the second reason. New engines and gears can take weeks or months to arrive, so ordering in the fall gives parts time to land before spring. If you're still deciding whether a repower is the right call at all, the best thing to do is contact us to discuss the situation and determine possible budgets and next steps.
Plan Your Repower with Hatton Power & Propulsion
The engine is only part of a repower's cost, and planning it in the off-season keeps the budget and timeline under control.
We've handled marine repower work in Seattle on commercial and pleasure vessels for more than 25 years. As an authorized dealer for Cummins, John Deere, Yanmar, Mitsubishi, Scania, Kubota, and Isuzu, plus ZF marine gears, we source, install, and support your engine with parts for as long as you own the boat. That covers everything from commercial vessel repower work to pleasure craft service.
For an accurate quote, have your vessel's make, model, and length ready, along with the current engine, its hours, and how you use the boat. Have a question first? Contact our service team.
FAQ
How much does it cost to repower a boat with a diesel engine?
Most of the diesel repowers we do fall within the ranges in the table above. As with any boat repair, where a job lands depends on horsepower, access, reusable equipment, and what we find once we remove the old engine, so we quote after we've seen the boat.
How long does a boat repower take?
Once the engine is on hand, a repower usually takes several weeks in the shop or yard, depending on access and how much supporting equipment changes. Engine lead times can add weeks or months before work starts, so plan in the fall.
Is it worth repowering an older boat?
Usually, when the hull is sound and you plan to keep the boat for years. A repower adds reliability, fuel economy, a warranty, and resale value. If the hull needs major work, get a survey first.
