Generator Sizing: The Mistake That Ruins Liveaboard Dreams
Yacht Buyer's Compass | Minted Yachts
Most first-time buyers obsess over stateroom count, flybridge layout, tender capacity. Then they move aboard for their first extended cruise and discover their 75-footer can't run the air conditioning, watermaker, and galley appliances simultaneously without tripping breakers.
Generator undersizing costs owners $40K-80K in retrofits—or forces them to compromise on the liveaboard lifestyle they bought the yacht to enjoy. Here's what brokers see go wrong, and how to spec power correctly from the start.
The Math Most Buyers Skip
Standard builder configurations on 70-80ft yachts typically include dual 17-22kW generators. That's adequate for weekend use—running one AC zone, basic galley, electronics.
But liveaboard power demands are different. You're running multiple AC zones in Caribbean heat, making 50 gallons of water daily, operating full galley loads, charging dive compressors, powering washer-dryers. Peak loads easily hit 35-40kW.
The fix isn't always bigger generators. Sometimes it's load management systems that intelligently shed non-critical loads during peak demand. But that requires planning during the buying process, not discovering the limitation six months into ownership.
What the Survey Won't Tell You
Marine surveys check if generators run and produce rated output. They don't model your actual usage patterns or calculate whether the electrical system can support your lifestyle.
A 46-year-old entrepreneur bought a 2019 Azimut 77 planning to spend four months annually cruising the Bahamas with his family. Standard dual 20kW Kohler generators. Three weeks into their first extended trip, they couldn't run both AC zones plus the watermaker during afternoon heat without load-shedding. Retrofit with upgraded 27kW units plus new switchgear cost $68K. Lesson: Survey the electrical system for your intended use, not just current functionality.
The Upgrade Decision Point
If you're looking at yachts built for charter or light recreational use, assume the generator package is undersized for full-time cruising. Upgrading before purchase gives you negotiating leverage—the seller covers it or reduces price accordingly.
Post-purchase upgrades mean hauling the yacht, cutting into engine room space, potentially relocating fuel tanks or other systems. That $45K generator upgrade becomes $75K installed.
Ask your broker to calculate total electrical load for your planned usage. If peak demand exceeds 80% of generator capacity, you need more power or better load management. This conversation happens during survey negotiations, not after closing.
Generator sizing isn't glamorous. But it's the difference between living aboard comfortably and constantly managing which systems you can run simultaneously. Spec it right from the start, or budget for the retrofit you'll inevitably need.