Mainship 350 Trawler is a name that comes up frequently in Great Loop or coastal cruising conversations – and for good reason. Combining modern styling with the practical trawler lifestyle, the Mainship 350 offers comfort, efficiency, and a surprising amount of living space in a manageable, single-engine cruising package.
About Mainship
Mainship Corporation was founded in the 1970s as part of the Luhrs Marine Group, building efficient, comfortable trawler-style cruisers for the American market. Mainships are known for practical layouts for liveaboard cruising, fuel efficient propulsion, contemporary styling, and quality construction at an attractive price point. The Mainship line appealed to buyers who wanted economical cruising without sacrificing comfort, and they remain popular in the brokerage market today.
About the 350
The Mainship 350 Trawler (produced ~1995-2000) replaced the Mainship 47 and 40, eventually evolving into the Mainship 390.
Key features include:
- Semi-displacement hull – Allows faster cruising than traditional full-displacement trawlers while maintaining good fuel economy. Expect cruising speeds of 8-12 knots and top speeds around 14-16 knots, depending on engine and load.
- Single diesel power – Most are equipped with a 300 HP Caterpillar 3116 or similar, providing simple, economical operation with lower maintenance costs than twins.
- Expansive flybridge – The flybridge has ample seating and excellent visibility, making it a popular spot for travel days and dockside lounging.
- Large cockpit and swim platform – A spacious cockpit makes line handling and water access easy, while a molded staircase (not a ladder) connects to the flybridge, a notable convenience for many owners.
- Smart, open salon – Large windows, galley-up, L-shaped settee, optional lower helm station, and abundant storage.
- Nice headroom – About 6’3″ throughout the interior
Quick FAQ
Almost! The two models are closely related and have the same length, displacement, and engine options. The Mainship 390 replaced the 350 around 2000, using the same hull with minor modifications. The primary differences are in the interior layout, with the 390 featuring an updated interior arrangement, cabinet mounting, and slightly revised flybridge and deck layout. If you like the 350, you will likely appreciate the 390, with differences coming down to interior preferences and available equipment.
Most Mainship 350s are powered by a Caterpillar 3116, 300HP diesel engine, which is known for reliability and relatively low fuel burn. Some boats may have Cummins or Yanmar diesel options.
Yes, it is considered one of the best affordable Loop boats due to low fuel burn, comfortable layout, and low draft (both air and water).
Who Is the Mainship 350 Right For?
The typical Mainship 350 buyer values comfortable livability potential on a reasonable budget. They will likely prefer fuel-efficient cruising over high-speed planing en route to their next destination. They might be attracted by coastal cruising/ICW/Great Loop abilities and appreciate simple, easily maintained systems.
These boats are especially popular with:
✅ Great Loop cruisers seeking a capable, comfortable, and fuel-efficient vessel that can handle river systems and coastal legs.
✅ Couples who want a liveaboard or seasonal home on the water without stepping into a large, complex yacht.
✅ First-time trawler owners moving from sailboats or express cruisers, attracted by the single-engine simplicity and practical layout.
If you are shopping for a Mainship 350, it may be helpful to compare it against the Beneteau Swift Trawler 34. The ST 34 is a newer, more premium boat with modern styling and could be a benchmark to help you figure out your priorities. Gulfstar trawlers in the same length range could also help to understand where the Mainship fits in terms of build quality, systems, and resale value. Lastly, the Albin 36 Trawler is a narrower boat but highly regarded for quality.
Engines and Fuel Burn
- Caterpillar 3116 300HP diesel (most common)
- Some had Yanmar or Cummins options.
- 300 Gallons of Fuel
Fuel Burn / Performance expectations:
Most owners will cruise at 8-10 knots for maximum fuel efficiency. A Faster cruise at 12-14 knots when needed but will burn a lot more fuel. Theoretical fuel burn below:
| Speed (Knots) | Speed (MPH) | Fuel Burn (GPH) | Fuel Burn (GPM) | Approx. Range on 300 gal |
|---|---|---|---|---|
| 8 | 9.2 | 2.7 | 0.29 | 1,034 miles |
| 10 | 11.5 | 4.0 | 0.35 | 857 miles |
| 12 | 13.8 | 6.0 | 0.43 | 698 miles |
| 14 | 16.1 | 9.0 | 0.56 | 536 miles |
The single-engine setup is often paired with a bow thruster and even a sturn thruster. This makes docking and tight maneuvering manageable while reducing maintenance complexity compared to twins.
Final Thoughts: Is the Mainship 350 Right for You?
The Mainship 350 Trawler is a standout choice if you want:
✅ An economical, practical cruiser
✅ Capable Great Loop vessel
✅ Comfortable liveaboard space for a couple or small family
✅ Manageable maintenance and systems
✅ The versatility to travel slow or step up to a faster cruise when needed
If you’re considering moving from sail to power, the Mainship 350 provides many of the slow cruising benefits you’re accustomed to while offering a spacious, bright interior and reliable propulsion.
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