Mainship 390 Trawler

2001 Mainship 390 – Lil Unsteady
Well-Kept • Extensively Updated • Turn-Key Cruiser

Lil Unsteady is a standout example of the popular Mainship 390—a classic trawler-style cruiser known for efficiency, generous living space, and easy handling. Powered by a single Cummins 6BTA 330 with 4,672 hours, this boat has been regularly exercised, thoughtfully upgraded, and meticulously maintained by knowledgeable owners. The depth and detail of the maintenance history set this vessel apart.

Highlights

• Cummins 6BTA 330 (Single Diesel 4600 hours) – Economical, Simple, and Well-Supported

• Extensive service records and continual system upgrades

• Simrad electronics suite

• Excellent canvas & enclosure

• AB 10’ Tender w/ Yamaha 15HP electric-start & davit

• Recent shaft, coupling, cutlass bearing, and prop work (2025)

• Upgraded inverter & electrical system

• Major VacuFlush and plumbing renewals

• Swim platform structurally rebuilt and resealed

Standard Mainship 390 Features

• Spacious two-stateroom, one-head layout

• Large salon with excellent natural light

• Galley-up design with full appliances

• Wide side decks and safe walk-around design

• Upper and lower helms

• Flybridge seating with full enclosure

Notable Upgrades and Maintenance, 

• Electronics replacement (2021)

• Simrad system including:

• (2) NSS9 Evo3 MFDs (upper helm)

• Simrad Halo20+ Radar (2024)

• Autopilot controller, display & direction finder

• New transducer

• ACR Man-Overboard alarm system (2021)

• Secondary depth finder via SonarPhone (2019)

Engine & Transmission

• Cummins 1000-hour service completed 3/2025

• Heat exchanger serviced (2019)

• Aftercooler serviced (2023)

• New exhaust elbow (2022)

• New OEM Cummins starter (2018)

• Engine hoses replaced (12/2024)

• Transmission oil change (11/2023)

• Damper plate, bell housing & rear main seal replaced (11/2023)

Generator

• Professionally serviced by Southeastern Marine (2019)

• Fuel pump replaced (2019)

• Electrical connections cleaned (2021)

• Main breaker replaced (2021)

• Generator battery replaced (2021)

• Owner-performed full service (2021)

• Field rewound (2024)

• Generator board replaced

• Full service (2024)

Electrical

• Victron 12/3000/120 Multiplus inverter with shunt & display (2022)

• Promariner charger (2021)

• Starter batteries replaced (2021)

• House batteries partially renewed (2021)

• LED upgrades throughout: nav lights, stern light, deck lights

• Underwater lights (white or blue) installed (2025)

• New wiper motors & arms (2025)

Plumbing & Sanitation

• Extensive VacuFlush system rebuild (2025) 

• Water heater replaced (9/2024)

• Freshwater pump replaced (2023)

• Multiple bilge pumps replaced forward, mid, and aft (2021–2025)

• Faucets updated throughout, including galley (2025)

• Shower sump pump & float replaced

• Macerator pump replaced

Canvas & Eisenglass

• Flybridge enclosure (2020)

• New Bimini & Eisenglass (2020)

• Phifertex wrap and panels updated & restitched

• Bimini re-waterproofed (2024)

• Partial Eisenglass replacement (2025)

• Matching green canvas, lines, and fender covers

Air Conditioning

• (1) 16,000 BTU Dometic units (stateroom – 2019)

• (1) 16,000 BTU Dometic units (salon – 2025)

• New bronze piping from sea strainer to pump

Running Gear

• Dripless shaft seal (2021)

• Shaft, coupler & cutlass bearing replaced (2025)

• Propeller inspected & trued (2025)

• Stuffing box restuffed (2025)

Interior & Appliances

• Refrigerator (2025)

• Microwave (2025)

• Salon stereo (2025)

• Sansui salon TV (2024)

• New curtains (2022)

• Cabinet faces refinished & latches replaced (2025)

Tender & Deck Gear

• AB 10’ Dinghy

• Yamaha 15HP electric-start outboard (2018 / installed 2020)

• Dinghy inspected & repaired (2022)

• Davit system fully serviced (2020)

• Mantus anchor swivel & bridle

• 200’ anchor chain, marked every 25’

Hull, Bottom & Cosmetics

• Bottom paint: 2021, 2023, 2025

• Regular buff & wax through 2025

• Trim tab hinges replaced

Swim Platform – Major Rebuild

A known weak point on Mainships, this swim platform has been professionally rebuilt:

• Wet foam removed and replaced

• New raised access hatches

• New foam core on ends, glassed & gelcoated

• Davit resealed with spacers to properly shed water

Summary

Lil Unsteady is not just another Mainship 390—it is a deeply maintained, thoughtfully upgraded cruising trawler with significant recent mechanical, electrical, and structural work already completed. For buyers seeking a dependable, well-documented cruiser that’s ready to go without deferred maintenance, this boat deserves serious consideration.