Design and Construction
At the heart of the M-20 lies a flat-bottomed scow hull paired with twin centerboards, or bilgeboards, that supply lateral resistance without the intrusion of a centerboard trunk anchor. The hull measures 20 feet overall with a 14-foot waterline and a narrow 5.67-foot beam, and at 595 pounds displacement the boat is featherlight by any keelboat standard. That minimal mass, combined with the scow's planar underside, is what lets the design emphasize speed and planing ability on flat inland lakes. The twin-board arrangement also means the boat can be dried out or trailered at a minimum draft of just 0.67 feet, yet still reach 3.5 feet of board-down draft for upwind grip.
Rig and Handling
The M-20 carries a fractional sloop rig with a mainsail of 113.85 square feet and a jib of 62.27 square feet, giving a working sail area that, with the boat's low displacement, produces a lively power-to-weight character. A 293-square-foot spinnaker transforms the downwind leg, and the source describes the sail plan as powerful for thrilling downwind runs anchor. The mainsail's modest 4.5-inch head and 87.99-degree tack angle reflect the fractional, masthead-light configuration suited to a planing scow rather than a displacement cruiser. On the broad, wind-swept surfaces of the Midwest lakes the class was built for, that rig rewards athletic crew work and precise weight placement.
Racing and Class Life
Strong one-design racing under the Inland Lake Yachting Association and the North American Scow Sailing Association has kept the M-20 relevant decades after its design anchor. The class's continued presence on Geneva, Okoboji, and other lakes confirms that the ~675 hulls built formed a self-sustaining competitive fleet rather than a passing production run. For a 20-foot scow, that institutional support is the difference between a collector's curiosity and a boat you can still campaign on any summer weekend.
Ownership Context
Because the M-20 was created as a racing scow rather than a cruiser, its ownership story is about trailering, rigging, and fleet participation more than about systems and refits. The Melges name and the later Windward Boatworks hulls mean two builder lineages exist among surviving boats, a useful detail when tracing a specific hull's provenance.
The Verdict
The M-20 Scow is a purpose-built inland racer that trades creature comforts for planing speed and a deep one-design structure. Its twin bilgeboards and flat scow bottom are elegant solutions to the conflicting demands of shallow launch ramps and upwind performance, and the class's health makes it a rare vintage racer you can still sail competitively.
Pros
- Flat-bottomed scow hull with twin centerboards for lateral resistance without trunk intrusion
- Light 595-pound displacement enabling planing and excitement on flat inland lakes
- Active one-design racing under ILYA and NASSA with fleets still on Geneva, Okoboji, and beyond
- Fractional sloop rig with powerful spinnaker-driven downwind performance
Cons
- Purpose-built racer with no cruising accommodation or offshore intent
- Narrow 5.67-foot beam limits stability margin compared with wider sportboats
