McGruer already had a strong in-house pedigree at Grampian, having designed the 26, 30, and 23. That background shows in the Discovery 7.9: it’s a conservative, purpose-built little cruiser-racer rather than a fashion piece.
Design and Construction
The Discovery 7.9 is a solid-fiberglass monohull with a fin keel and transom-hung rudder. Its 5,100-pound displacement includes 2,300 pounds of lead ballast, for a ballast ratio of 45 percent—a substantial stability foundation for a 26-footer.
The boat carries a modest 8.33-foot beam on a 21.75-foot waterline. Its length-to-beam ratio is 3.12, while a displacement-to-length ratio of 221 places it among moderate racers. The compact underwater profile includes a loaded draft of about 3.74 to 4.04 feet, depending on burden, allowing the boat to settle into shallow marinas that deeper-keel boats can’t reach.
Wetted surface is roughly 193 square feet. An immersion rate of 631 pounds per inch indicates how little additional buoyancy the hull requires as crew and gear come aboard, with trim changing slowly under typical loads.
Rig and Handling
The Discovery 7.9 has a masthead sloop rig carrying 318 square feet of sail. Its sail-area-to-displacement ratio of 17.39 should provide enough power to keep the boat lively without demanding a racing crew.
The standard running rigging uses 3/8-inch line throughout. Jib and genoa sheets are 26 feet long, the mainsheet is 65 feet, and the spinnaker sheets measure 57.2 feet. Those dimensions reflect a simple, serviceable deck plan rather than an over-engineered one.
Theoretical hull speed is 6.2 knots, as expected for a displacement hull of this waterline length. With its moderate displacement and 193 square feet of wetted surface, the Discovery 7.9 is neither a featherweight nor a slug.
Stability and Seakeeping
The capsize screening value is 1.94. By the standard formula alone, that figure would admit the boat to offshore consideration for its length. Paired with the 45 percent ballast ratio and fin-keel profile, it suggests a small boat with a serious stability foundation rather than a pond racer.
A motion comfort ratio of 20.2 describes a short-bodied boat that will feel the sea more than a longer cruiser, though it remains within normal bounds for this size. Combined with the boat’s 3.12 length-to-beam ratio, that points to lively motion in a seaway.
Verdict
The Grampian Discovery 7.9 is a tidy, well-ballasted small sloop from the final years of a Canadian builder that knew its craft. McGruer’s design is numerically coherent: a 45 percent ballast ratio, fin keel, modest wetted surface, and manageable draft make for a stable, handy 26-footer that can tuck into shallow harbors.
Its brief 1975–1977 production run means the number of surviving hulls is finite. Even so, the boat remains a sensible expression of mid-1970s cruiser-racer thinking.
Pros
- High 45 percent ballast ratio for its size, with 2,300 lb of lead ballast
- Shallow enough draft to enter marinas that deeper boats can’t reach
- Capsize screening value of 1.94 and moderate-racer displacement-to-length ratio
Cons
- Short independent production run from 1975 to 1977 limits the number of available hulls
- Length-to-beam ratio of 3.12 and comfort ratio of 20.2 point to lively motion in a seaway
