These rules are listed in the article as being updated in 2007.
These revised Vintage Marblehead Rating Rules of 2007 shall govern Vintage Marblehead activities from date of publication until revised by consensus or recommendation by Vintage Marblehead class owners.
The rating rules for the Vintage M divisions are based on the Marblehead 50-800 Class rule adopted by the Model Yacht Racing Association of America (predecessor of the American Model Yachting Association) April 14, 1932 and corrected to June 1, 1939. Subsequent editions were “corrected” to accommodate the evolving Marblehead 50-800 development class.
Traditional Vintage Marblehead
Design Formula
A sloop-rigged monohull model sailing yacht with an overall maximum length of 50 inches, plus or minus one quarter of an inch, and a total sail area not to exceed 800 square inches.
Prohibited:
- Sliding or adjustable keels
- Centerboards
- Leeboards
- Bilge-boards
- Bowsprits
- Transom-mounted rudders or rudders that extend aft of the transom
- Outriggers, pontoons, or twin hulls
- Moveable or shifting ballast
- Prognatheous keels: No portion of the keel appendage, including the lead, may project forward of the leading edge of the keel fin
- Metal fin keels
- Materials with a density greater than lead
- Carbon fiber or Kevlar in the hull, rudder or rig
- Fabric, film, balsa, foam or fiberglass decks
- Mylar or other modern plastic-like materials in sails
- Swing rigs
Hull
Hulls shall be constructed by the methods and of the materials of the period as follows:
Hulls shall be constructed primarily of wood, using plank on frame or horizontal and vertical lifts. It is permissible to cover a wood hull with a light layer of fiberglass cloth to add strength and prevent leakage. Balsa strip planking covered with fiberglass, in which fiberglass is the primary strength of the hull, is not permitted.
Fiberglass hulls laid up in a mold are permitted. Minimum weight of fiberglass hulls is two (2) pounds.
Garboards: Garboards shall be hollow, with not less than a one inch radius in the area of the keel fin. This may be checked by use of a disk 2 inches in diameter, fitted to the garboard at a midship section.
Modern adhesives are permitted to produce a strong hull impervious to leaks.
Draft shall not exceed 12 inches on a model yacht fully rigged and ready to sail. Minimum keel fin chord length shall be five inches.
All ballast must be fixed and shall not be changed during a race or series of races.
Model total weight shall be in keeping with that of the period. Bumpers are mandatory and are limited to one half inch overhang.
Bumpers are not included in the overall hull measurement.
Rudders shall be keel- or skeg-mounted in keeping with the design characteristics of the period. It is permitted to enlarge the area of the rudder from its original size to achieve acceptable steering with radio control. The skeg must be at least 50% of the rudder in area when the rudder is skeg-mounted. Balanced or spade rudders are not allowed. Changing rudders during a race or series of races, except in bona fide cases of damage, is prohibited.
Deck
Decks shall be constructed of wood: solid, planked or plywood. Film, cloth, foam, balsa or fiberglass decks are not allowed.
Rig
Bermuda, Marconi, jib-headed mainsail, gaff, gunter, wishbone and other types may be used.
Alternate rigs are permitted provided the sail area does not exceed 800 square inches. Details of such rigs must be comparable to the original sail plan.
Spars shall be constructed of the materials of the period, primarily wood. Round aluminum tubing is permitted. Modern extruded aluminum spars, designed and produced for modern model sailboats, are not permitted.
Maximum diameter of spars is ¾ of an inch.
Maximum height of the head of the mainsail above the deck (see sail measurement) is 85 inches.
Height of the jib head stay above the deck shall not exceed 80 percent of the height of the head of the mainsail above the deck.
Hollow masts and spars, permanently bent masts and spars, and rotating and bipod masts are allowed.
Fittings
Fittings for deck and rig should be made of brass in keeping with materials and practices of the period.
Sails
Sails shall be constructed by the methods of the period.
Sails may be constructed as either a single or multi-panel sail.
The body of each sail shall be made of woven cloth, such as cotton, a cotton-synthetic blend, Dacron or Nylon, such as light spinnaker cloth. No material other than woven sail cloth is allowed for tablings or corner reinforcements in the head, tack or clew of any sail except sail reinforcing tape.
Mylar or other modern plastic-like materials are not allowed.
Roach of sails shall not exceed two inches. Rounded foot of loose-footed sails shall not exceed one inch.
The roach and the rounded foot of sails shall be a continuous, arc-like curve from head to clew and from clew to tack.
Mainsail battens shall not exceed four in number and four inches in length and they shall divide the mainsail leach into approximately equal parts. Headsail battens shall not exceed three in number and two inches in length and they shall divide the headsail leach into approximately equal parts.
Headsticks or headboards shall not exceed ¾ of an inch across the base for headsails and mainsails. No other wire or stiffener shall be put in the head of the sails
Sail measurement
Rig and mainsail measurements are taken from the underside of the ¾-inch base of the mainsail headboard. Thus, the height of the mainsail above the deck measurement and the area of the mainsail are taken from this point.
Calculation of sail area:
The measurement of sails is specified in the 1958 MYRAA Handbook. Only the actual sail area, excluding roaches and the rounded foot of loose-footed sails is measured. The above drawing indicates the layout for triangular sails. The luff is measured from the lowest point on the tack of the sail to the bottom edge of the stick or headboard. If the sail has no headboard, the measurement is taken from a point at the head of the sail where its width is ¾ of an inch. The diagonal is measured from the aft edge of the clew to the closest point on the luff. The sail area of each sail is given by: Sail Area = luff measurement x diagonal measurement /2. The sum of the areas for the jib and mainsail must be less than 800 square inches.
All Vintage Marblehead Yachts shall be officially registered with the VM class Coordinator to obtain an official sail number. Sail numbers shall be preferably black, three inches tall, ½ inch in thickness and they shall be affixed to both sides of the mainsail between the second and third battens on a line perpendicular to the leach. The VM insignia consists of a red “V” nested in the top of a black “M”. The letters are 1 ½ inches tall, 1 ¼ inches wide and ¼ inch thick. The “V” is separated from the “M” by 1/ 16th inch. The insignia should be placed in the upper quadrant of the mainsail and only on the starboard side.
Radio Control
Only the rudder, headsail sheet and mainsail sheet may be adjusted by radio control.
High Flyer Vintage Marblehead
The rules for the High Flyer division are the same as those for the Traditional division except for the following:
High Flyer Marblehead hull design, rig, sails and keel configurations must follow those of the period.
Rudders may be of the spade or balanced type; that is, independently suspended and not attached to the keel or a skeg. Marbleheads of any design of the Traditional period that use a spade rudder shall be classed with the High Flyer division.
Draft of a High Flyer model yacht fully rigged and ready to sail must not exceed 16 inches.