Go to the M-20 Association Yearbook online.

History of the M20

M-20 Scow - A beginner's primer
by James Bland, Past-Commodore, M-20 Sailing Association

The scow is truly an American invention in one design sailing. The scow has its origins traced to broad beamed, vastly over canvassed racing sloops called "Sandbaggers", which used large crews and moveable bags of sand for ballasting. The scow design was largely an outgrowth of the racing for the Seawanhaka Cup donated by the Seawanhaka Corinthian Yacht Club to promote interest in small yachts. Herreschoff and others had demonstrated the effectiveness of the light displacement broad-beamed "skimming dish" hull type. Glencairn, the 1896 Seawanhaka Cup challenger from the Royal St. Lawrence Yacht Club, was the first true scow and she defeated Clinton Crane's El Hierie easily.

When heeled, Glencairn's flat section became a canoe like form with greatly reduced waterline beam, and the waterline became elongated both foreward and aft, with the waterline plane becoming symmetrical. In shifting the heeled center of buoyancy farther to leeward, the greater righting moment of hull and crew permitted a larger sail plan on the same beam.

The freak scows won over their strongest opponents when they began to beat the sandbaggers, not only in light air, but in a breeze as well. It was soon evident that the extra weight of the sandbags merely slowed the boats off the wind and the difficulty of moving dozens of sandbags with each tack simply reduced maneuverability. A properly designed scow, with its reduced wetted surface area, longer heeled waterline, and effective planing surfaces downwind, could be effectively sailed by a few crew members.

In 1898 the Canadian boat, Dominion, carried the scow design to its logical end. She was essentially two semi-circular section hulls with a joining elevated floor above the waterline. When heeled, her waterline increased from 17'6" to 27 feet. She won the 1898 Seawanhaka Cup with ease, unbeatable in any condition. Her superior design was subsequently ruled illegal for the Seawanhaka Cup competition. Dominion would later be part of the inspiration for the M-20 design.

In the winter of 1898, eighteen clubs from Indiana to Minnesota sent representitives to a Milwaukee meeting which formed the Inland Lake Yacht Association and formulated a set of rules for two classes to race without handicaps in interlake competition. The rules fostered the rapid development of the Inland lake scows.

The M-20 is one of the newest scows in the Inland family. It was designed by Harry Melges Sr. and Harry (Buddy) Melges Jr. as the scow version of the Olympic Flying Dutchman class. This was the second in the M series, a tunneled hull sloop with spinnaker especially designed for two people. Five different M-20 hulls were built of wood and each was tested against its successor to find the better boat. Finally, in December of 1962, a prototype was produced out of fiberglass. She handled beautifully in all weather conditions and took a sea better than any other scow. The first M-20 competed in Yachting's One-Of--A-Kind Regatta and turned in the fastest elapsed time of all monohulls.

The M-20 must be considered an advanced scow design and will remain so for years to come. Its high aspect sail plan is similar to the America's Cup Technology currently in use today, and provides a wide range of controls for all wind conditions. The tunneled hull of the M-20 is her most unique feature and provides increased stability and structural stiffness.

The M-20 is 20' long and 5'8" wide. The tunnel of the hull is refers to the fact that the middle section of the bottom is 3" shallower than the bilges on each side of the boat. This tunnel promotes planing , and aids winward performance. The boat is sailed heeled, with the bilgeboards becoming perpendicular to the waters surface at 25 to 30 degrees of list. Sailing the M-20 heeled reduces wetted surface area and lengthens the waterline. With the bilgeboards down the boat draws 3'6", and 8" with the boards up. The boards are slightly toed in to provide a lifting surface for increased upwind performance.

The modern sail plan is mounted on a 26 foot mast and 9'6" boom. The M-20 carries 176 square feet of sail and a powerful 300 square foot spinnaker for offwind speed. A full set of sail adjustments keep the skipper and crew on their toes. An adjustable permanent backstay and flexible spar allow competitive crew weights to range from 270 to 450 pounds. as a result the M-20 is popular with families. Male/Female teams, older teenagers, as well as two man teams all compete successfully in this versatile dingy.

The M-20 is a real value. Sound, stiff hulls manufactured in 1978 are still winning national championships, and the used M-20 market is active with a few boats currently available, ranging from $2,500 to $10,000 depending on equipment. The M-20 is a great boat to sail and for people considering national sailing campaigns, it is a must-have experiance. The class membership is stable and features quarterly newsletters and a yearbook.( Material in this article was based on Stuart Walker's book on Performance Advances in Small Boat Racing, 1969)


M-20 Association©2013