Mainship 390 Trawler, the Couple's Loop Boat Reviewed

Why the Mainship 390 still sells two decades later

The Mainship 390 was never the most beautiful or best-built trawler of its era. It succeeded because it nailed what an American couple actually wanted at the turn of the millennium: a comfortable owner's cabin plus a small guest cabin instead of three cramped ones, a single diesel that is cheap to run, a cockpit at dock height for line handling, a flybridge for good-weather cruising, and a price far below the Taiwan-built trawlers it competed with. Built by Mainship in Midway, Georgia, then part of the Luhrs Marine Group, the 390 became one of the defining boats of the early 2000s trawler boom.

Two decades later the Mainship 390 is still a regular at Great Loop rendezvous, and buyers who search for a Mainship 390 for sale are usually Loop planners on a realistic budget. The boat's strengths line up almost perfectly with the Loop's demands, and its weaknesses are well known and fixable.

Two cabins on a 14 foot beam, and why couples love it

PowerBoat Guide calls the 390 a very roomy boat inside thanks to its 14 foot 2 inch beam, and the floorplan fits double berths in both staterooms plus a head with a separate stall shower. The guest stateroom is partially tucked beneath the galley, so it suits occasional visitors, grandchildren or storage, while the owners get the better cabin. The saloon and galley share the main deck with a lower helm, and a sliding glass door opens to the covered cockpit.

Visibility from the lower helm is excellent, a deck door gives quick access to the foredeck, and deep, well-protected side decks make line handling safer in locks. Molded steps rather than a ladder lead from the cockpit to the extended flybridge, and the interior is finished in teak. Couples who cruise for months use the second cabin as an office or gear room; families who carry guests every weekend should compare it with Mainship's larger 400 Trawler.

• Double berths in both staterooms
• Guest stateroom partially tucked beneath the galley
• One head with a separate stall shower
• Lower helm with a deck door to the foredeck
• Molded steps from the covered cockpit to the extended flybridge

Single diesel economics and range at 7 knots

Most Mainship 390s were delivered with a single diesel turning a propeller protected by a shallow, full-length keel. PowerBoat Guide notes that a single 300 hp Caterpillar cruises the boat at 10 to 12 knots with about 14 knots on top, while twin 230 hp Yanmars cruise at about 14 knots and reach 18 to 19. Because ratings and engines differ by year, check the engine data plate on any boat rather than relying on the listing.

The 390's modified-V hull, with flat aftersections and a shallow keel, has two useful speeds. At 7 to 8 knots it burns roughly 3 to 4 gallons per hour, according to typical owner reports for single-diesel boats of this size, which gives a comfortable cruising range of several hundred nautical miles. At its fast cruise in the low to mid teens, consumption rises sharply, so most Loopers run at displacement speed nearly all the time and keep the speed for running from weather or making a lock opening.

The boat carries 300 gallons of fuel and 130 gallons of water, but no published range figure exists for it, so we leave range blank in the specification table. Plan with the boat's actual tank sizes, its fuel log and a 20 percent reserve.

Great Loop specifics for a Mainship 390

Air draft is the first thing to check. The Chicago route has a fixed bridge near Lemont, Illinois with about 19 feet 1 inch of clearance, and the western Erie Canal is lower at about 15 feet 6 inches. Most 390s have a flybridge with a hardtop or bimini and a radar arch, so owners lower the arch, fold antennas and sometimes remove items to clear Chicago. Measure the actual boat before buying and plan the Oswego route for the Erie.

Draft and size are friendly. At about 3 feet 8 inches, the 390 draws little enough for the rivers, the ICW and most Bahamas anchorages, and at 39 feet nominal length it fits transient slips and lock chambers comfortably. A bow thruster, if not already fitted, is the most worthwhile upgrade for single-engine lock work.

The known weak spots and how expensive they are

Experienced surveyors check the same items on every 390. Fuel tanks are the big one on boats approaching 25 years of age; replacement can require cutting access through the cabin sole and is costly. Decks and flybridge sole areas can absorb water around fittings. Windows may leak, especially the large saloon windows. Exhaust elbows and risers on the single diesel are wear items.

None of these issues are unique to Mainship, and none are dealbreakers if priced correctly. A boat with documented tank replacement or a recent exhaust job is worth noticeably more than one where those jobs are still waiting.

What a 390 costs to run each year

Plan on roughly $15,000 to $32,000 per year excluding depreciation. Slip fees for a 40-foot boat vary widely by region; insurance is moderate but older boats may need a recent survey; engine and generator service, bottom paint and canvas replacement are the regular items. Fuel costs on the Loop are lower than for almost any other boat this size thanks to the single diesel.

Because the 390 is no longer built, model-specific parts come from the owner community and used parts dealers. Mechanical items are standard marine parts and easy to source.

Mainship 390 versus the later 400 Trawler

Mainship followed the 390 with the larger 400 Trawler. If you plan to have guests often, walk through both boats and compare the layouts. If it is just the two of you, the 390's compact two-cabin layout and lower price usually make it the better value.

Mainship later offered the 414 Trawler and the 35 Trawler before production ended. Each generation has its fans, but the 390 remains the most common Mainship trawler on the Loop and its price stays firm because of that.