Boston BoatWorks and mJm Yachts: Lightweight, Efficient Powerboats

When four sailors pooled their skills to build powerboats, the result was unexpected and compelling: vessels that combine the sensitivity of sailing experience with the speed and convenience of powerboats. Sailors bring a refined awareness of wind, current, tide and seakeeping that influences the way these powercraft are designed. Boston BoatWorks (BBW) and mJm Yachts translate that nautical understanding into boats that prioritize efficiency, structural integrity and light weight—factors that translate directly into better performance and reliability.

Founders, Philosophy and Early Experience

Mark Lindsay and Scott Smith founded Boston BoatWorks with a craft-first mindset. Both brought deep sailing backgrounds and strong interests in materials, structure and speed. Lindsay’s lifelong curiosity about how boats work—rooted in years of sailboat racing, architecture studies and composite experimentation—led him to refine light, strong laminates and structural solutions. Smith’s hands-on experience restoring an old wooden sloop informed his insistence on durability, low maintenance and practical design.

Together they pursued advanced composite construction techniques and optimized hull forms to minimize resistance and weight. Their goal: make planing powerboats that are lighter, faster and more fuel-efficient without sacrificing safety or seaworthiness.

Why Weight Matters

Weight is the defining factor for planing hull efficiency. Lighter boats accelerate faster, plane sooner, consume less fuel and reduce engine size requirements. To achieve that light-but-strong balance, BBW relies on prepreg epoxy vacuum-bagged laminates. Epoxy outperforms polyester and vinylester in elongation, toughness and adhesion, producing laminates that can take higher loads and resist osmotic blistering. Prepreg processes precisely control resin content, minimizing excess resin that adds weight and weakens the laminate.

For sailors accustomed to ballast-driven stability, powerboat stability works differently. Planing hard-chine hulls rely on form stability; keeping weight low is still beneficial because it reduces wetted surface and drag. BBW’s approach is therefore straightforward: reduce overall mass while preserving strength and stiffness with advanced materials and construction methods.

Advanced Composite Construction

Boston BoatWorks builds to European CE standards and uses a consistent process to achieve exceptional strength-to-weight ratios. Exterior gelcoat is followed by a vinylester tie coat and an epoxy skin coat. BBW’s in-house impregnator precisely wets fiber to a 60/40 fiber-to-resin ratio—opposite what’s typical in open-mold production—yielding stronger, lighter laminates. The hull uses Kevlar in the outer skin for impact resistance and biaxial fiberglass layers for uniform stiffness.

Core-Cell foam cores separate thin outer and inner skins, creating an efficient sandwich structure. Hull and deck components are vacuum-bagged to compress the laminate, eliminate voids and ensure a tight bond to the core. Stringers and bulkhead landings are glassed in as an integrated grid, producing a structure reminiscent of aircraft composites in its fatigue resistance and load distribution.

Key structural areas—keel, chines and sheer—use solid glass where loads are concentrated. The hull is molded in two halves to accommodate tumblehome and complex shapes, then joined and vacuum-bonded to achieve continuity and strength. Post-cure at elevated temperature completes the epoxy crosslinking before final assembly and a high-strength methyl methacrylate bond joins hull and deck.

mJm Yachts: Design, Simplicity and Efficiency

mJm Yachts, owned by Bob Johnstone (founder of J/Boats), partners with Boston BoatWorks to produce a family of lightweight, elegantly proportioned powerboats. Johnstone’s brief was simple: a well-engineered, uncluttered boat that’s easy to own and operate. He rejected what he called “featuritis”—excessive onboard systems that add weight, cost and maintenance—and favored clean, efficient outfitting.

Designer Doug Zurn delivered a low-slung, slender profile that balances aesthetics with seaworthiness and efficiency. The 34z, for example, was designed as a single-diesel cruiser capable of a comfortable 25-knot cruise and nearly 2 nautical miles per gallon—an indication of how shape and light weight produce real-world fuel savings.

Models, Propulsion and Performance

The mJm lineup includes the 29z, 34z, 36z and 40z, each available in Express or Downeast pilothouse configurations. Decks are level fore to aft to maximize cockpit volume, and arrangements favor topside cruising and entertaining. Power options range from bracket-mounted outboards on the 29z to efficient Volvo IPS or diesel sterndrives on larger models.

Because the boats are lighter—sometimes thousands of pounds lighter than conventionally built counterparts—smaller engines and pod systems achieve equal or better speeds with significantly improved fuel economy. For example, the 40z returns roughly 1.3 nmpg at 24 knots, which compares favorably to many heavier 32–36-foot cruisers. Twin four-stroke outboards, when properly trimmed, can be as efficient as diesel inboards at cruise, and IPS pod drives typically offer 20–30% efficiency gains over conventional shaft-driven inboards.

Production and Certification

Since BBW began building mJm models in 2003, more than a hundred hulls have been delivered. Construction adheres to CE standards, which include noise and emissions limits, additional safety equipment and certification for specific operating categories. For instance, the 40z is CE-certified for offshore conditions up to 45 knots and seas up to 21 feet, with the usual caveat that those conditions won’t coincide.

Base pricing (indicative) listed by the builder at the time of publication: 29z from $318,000, 36z from $467,000 and 40z from $795,000, with loaded options raising those figures. These prices reflect the high-quality materials, precision construction and performance-focused design that define the line.

Conclusion

Boston BoatWorks and mJm Yachts have created a compelling alternative to conventional production powerboats by combining sailboat-derived sensitivity, high-end composite techniques and efficient propulsion choices. The result is a range of boats that are lighter, stiffer and more economical on the water—built for boaters who value simplicity, reliability and seaworthy performance.

About the author: Eric Sorensen founded the J.D. Power and Associates marine practice and wrote Sorensen’s Guide to Powerboats: How to Evaluate Design, Construction and Performance. He consults for builders, agencies and owners and can be reached at [email protected] or (518) 324-7700.

This article originally appeared in the July 2010 issue.