Mainship 430 Trawler, a Broker's Review of the Fast Aft Cabin Mainship

Mainship's comeback boat, and why trawler buyers still search for it

Anyone typing Mainship trawlers for sale into a search bar eventually lands on the 430, the biggest boat in the builder's late 1990s trawler revival. Mainship had started in 1978 with a frugal single engine 34 footer, drifted into Eurostyle sport cruisers in 1988 and then came home with the 350 Trawler in 1996. The 430 Trawler followed in 1999 as the flagship of that return, built at the Diesel Road plant in St. Augustine, Florida, and sold through 2006, according to Power and Motoryacht's used boat review.

The concept was simple and very American: take the traditional trawler profile that the Grand Banks 42 made famous, widen it, and put it on a semi-displacement hull with twin diesels big enough to cruise in the teens. Richard Thiel's test for Power and Motoryacht noted the 430 is 1 ft 5 in beamier than a Grand Banks 42 and, at a listed 36,000 lb, about 2,000 lb heavier, which is a lot of boat for what Mainship charged.

That combination of volume, low exterior maintenance and two speeds is why the 430 keeps appearing on Great Loop shortlists. Broker Curtis Stokes told the magazine that experienced owners were buying them precisely because they were done with varnishing teak, and that the two stateroom galley-down layout was the one buyers asked for most.

A heavy hull that can loaf or hurry

The 430 is not a displacement trawler, and owners should not run it like one at every throttle setting. The bottom carries a keel and a sharper entry than the early Mainships, with a modest 12 degree deadrise that flattens toward the transom so the boat climbs onto plane. One magazine test recorded it on plane in nine seconds. Overall length is 47 ft 9 in including the integral pulpit, 43 ft without it, with a 15 ft 6 in beam and only 3 ft 8 in of draft.

That shoal draft is the quiet selling point for East Coast and Bahamas cruising. A 430 can poke into anchorages that a deep keel passagemaker cannot, and the weight helps in a chop. One owner quoted by Power and Motoryacht brought his 2003 boat up Long Island Sound in 6 to 8 foot seas and 25 knot winds at 12 knots and described the ride as surprisingly composed.

What the Power and Motoryacht test actually measured

Power and Motoryacht's test boat had twin 350 hp Caterpillar 3116 diesels, Hurth gears at 1.96:1 and 24 x 26 four blade props. Its full table is reproduced below in knots. The headline number is efficiency at displacement speed: 8.5 knots at 1,250 rpm for 6.6 gph, or about 1.28 nautical miles per gallon and a theoretical range near 578 nautical miles. At 750 rpm the boat crawled at 4.7 knots on 1.8 gph.

At the top, the same boat reached 17.4 knots (20 mph) at 2,800 rpm on 34 gph. Mainship's own press kit quoted other magazine tests claiming about 20 knots with similar Cats and half loads, and a separate test logged 16 knots at 2,400 rpm on roughly 26 gph. Expect real world numbers between those, depending on bottom condition and how loaded the boat is.

Boats with the twin 440 hp Yanmars are quicker. Ed McKnew's PowerBoat Guide, quoted in the same magazine, put 370 hp Cat boats at 17 to 19 knots on top and the larger engines close to 22 knots, while an owner with Yanmar 440s reported 8 knots at about 5 gph and 10 to 12 knots at 10 to 12 gph.

Galley up with three cabins, or galley down with two

Mainship launched the 430 as a three stateroom boat with the galley up, to port of the lower helm. The master is aft, down three steps from the saloon, with a queen berth set athwartships to port, a private head with stall shower to starboard and its own door to the small aft deck. Forward there is a V-berth guest cabin, and a third cabin to port with twin berths that tuck partly beneath the galley sole. A shared head with separate shower serves the two forward cabins.

In 2000 the yard added a two stateroom version after running owner focus groups. It drops the third cabin, moves the galley a few steps down and opens up the saloon with modular furniture. Brokers say it is the more popular choice with couples, because the guest cabin becomes a proper stateroom and the saloon feels much bigger. The three cabin boat, by contrast, suits families and is the one charter fleets liked.

Detail touches in both versions include a seven cubic foot chest freezer hidden under the raised lower helm seat in the three cabin boat, Corian counters, a computer desk under the electrical panel, side doors at the helm and galley, shore power inlets at both bow and stern, and a split anchor locker. Headroom is about 6 ft 3 in to 6 ft 6 in depending on the source.

Wide decks, a tender-sized boat deck and a flybridge for eight

Outside, the 430 is laid out for cruising couples who handle their own lines. Side decks are protected by high bulwarks and aluminum rails, the cockpit is stepped down close to swim platform height for easy boarding and tender work, and the roof of the aft cabin forms a boat deck large enough for a dinghy. Owners commonly add a davit or use a boom off the factory radar mast.

The flybridge seats up to eight around a table, with a centerline helm forward and a hinged console that tilts up for wiring access. Testers found the far forward helm takes some getting used to when backing into a slip, and almost every used boat has the optional bimini and enclosure, so budget for tired isinglass.

How it was built, and the systems that age

Power and Motoryacht listed hand-laid fiberglass with Coremat above the waterline, Baltek balsa coring in the decks and portions of the hull, and FRP-encapsulated plywood stringers. That is a conventional production recipe of the period. It works well when deck hardware is properly bedded and poorly when water gets into a cored deck around stanchions, cleats and the windlass, so a moisture meter survey is not optional.

Engine access is through lift-up companionway steps forward and three saloon sole hatches, with about 4 ft 4 in of headroom between the engines. Standard kit included Racor filters, an 8 kW generator, three air conditioning zones and bronze raw water strainers, and most boats also carry the bow thruster, windlass, synchronizer and oil change system from Mainship's option packages.

Buying one in 2026, ex-charter boats and price traps

The youngest 430 is now about 20 years old, so the price gap between a cared-for boat and a neglected one is large. Brokers warned years ago that high-hour former charter boats were dragging asking prices down and creating unrealistic expectations, since bringing one back can be open-ended. That still applies. A cheap 430 with original canvas, cloudy electronics and 5,000 hour engines is rarely cheaper in the end.

We estimate most 430s trade between about $110,000 and $260,000 in 2026, with the best late boats on Yanmar or Cummins power at the top. Annual running costs of roughly $18,000 to $36,000 cover a 45 to 50 ft slip in most of the Southeast, insurance, a haul and bottom job, twin engine service and a reserve for canvas and electronics.

Where the 430 sits in the Mainship family

Mainship's later 390 and 400 trawlers are single engine sedans that most buyers consider more economical but slower. The 430 is the twin engine, aft cabin option for owners who want privacy between cabins and the ability to run at 15 knots. In July 2012 a New Jersey bankruptcy court approved the sale of selected Mainship and Luhrs assets, along with Hunter Marine, to David Marlow's Marlow Acquisitions. The revival plans the new owners described to Power and Motoryacht centered on smaller models such as the former 355, so the 430 remains a used-only proposition and parts support runs through the owner community and engine dealers rather than a factory.