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Marlow Mainship 34


Lots of boats that qualify for the express genre offer only one drive-train configuration and two usable sets of speeds: high and low. The Marlow Mainship 34 is different, however. She can be ordered with either a single- or a twin-engine propulsion package, and, if our test of the twin-engine version is any measure, seems to run pretty well not only at high and low speeds, but at mid-range speeds as well.


We sea trialed our test boat on Tampa Bay under benign weather conditions—the sun was high and the seas were not. The most noteworthy aspect of her performance was her true-tracking nature. She holds a course for whole minutes at a time without a smidgen of input from the driver. Moreover, our 34 was relatively agile and well behaved in turns, although said turns were broad, as befits a straight-shaft, twin-engine vessel. Bow rise topped out at a little over five degrees and, thanks to the height of the helm seat, we had no trouble maintaining sightlines forward coming out of the hole, even without deploying the tabs. Maneuverability dockside seemed good too, even minus the presence of a bow thruster. Most owners of presumably very economical single-engine versions will likely add the thruster option, of course.



Marlow Mainship uses modern methods and materials to create the 34. Her hull is entirely cored with Nida-Core, an exceptionally strong and resilient sheet-type sandwich made up of an interstitial layer of interconnected, honeycomb-like octagons bonded between two non-woven polyester scrims. A vinylester-resin-infusion process anchors the Nida-Core between the inner and outer layers of the fiberglass hull and an all-glass, structural-foam-filled “stringer grid” strengthens and stiffens the hull from inside. Marlow Mainship chief David Marlow designed the hull-to-deck joint to prevent water intrusion through the screw holes that typify the conventional, shoebox-type joint. Basically, two outward turning flanges are juxtaposed (one emanating from the deck and the other from the hull) and then thoroughly sealed with 3M 5200, a semi-flexible, permanent agent. Mechanical fasteners, along with a rubrail and bang strip, are run through outboard of the seal so that water cannot enter. Kevlar and carbon fiber reinforce areas along the keel and at the base of the stem, as well as in way of the “strut keel” that protects the propeller or propellers. Aspects of onboard engineering are top notch—for example, there’s one fuel tank, located over the longitudinal center of gravity to obviate fuel-burn-related trim issues and a strong but lightweight, aeronautical-style, longitudinal framing system that features several beefy ring frames.


The 34’s layout is simple, with an island berth up forward in the accommodation spaces below decks, flanked by two cedar-lined hanging lockers. Further aft, there’s a galley and head (with separate shower stall) to port and a U-shaped dinette to starboard. Topside, a set of swiveling helm seats is forward, with reversible lounge seats and tables just behind. Folding cleats in the cockpit are massive. And decks, both under the hardtop and beyond, are coated with SeaDek, a non-absorbent, closed-cell copolymer product that resembles teak decking.

Marlow Mainship, 800-771-5556;

  • : 39’8”
  • : 12’4”
  • : 2’8”
  • : (half load): 15,000 lb.
  • : 280 gal.
  • : 105 gal.
  • : 2/260-hp Yanmar 6BY3-260 diesels
  • : $335,900 (w/single Yanmar)
  • : $475,957
  • : 7.5-kW Gen-Tec (optional)
  • : 2/220-hp Volvo Penta 6BY3-220 diesels or 1/350-hp 8LV-320 diesel
  • : ZF 63A; 2.52:1 ratio
  • : 22 x 18 4-blade bronze
RPM Knots GPH Range db(A)
600 4.3 0.8 1355 67
1000 5.6 1.2 1176 71
1500 7.2 1.6 1134 74
2000 8.2 4.8 431 77
2500 10.6 9.2 290 80
3000 14.7 12.4 299 82
3500 17.4 16.4 267 85
4100 23.9 25.0 241 90
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