Design and Construction
BK Marin built the Mamba 29 in solid fiberglass with a fin keel offered in iron or lead, and the boat was also sold to be home-completed, so the quality of each boat may vary. The hull carries 3,086 pounds of ballast at a 44 percent ballast ratio, higher than 69 percent of comparable designs, and the beam of 9 feet 7 inches against a 28.5-foot length gives a length-to-beam ratio of 3.04 — roomier than 54 percent of similar boats. A displacement-length ratio of 255 places her among moderate racers, while a capsize screening value of 2.00 means she would not be accepted in ocean races, a useful boundary marker for a boat whose natural business is sheltered-water sailing.
Rig and Handling
The fractional sloop rig is slightly overrigged, carrying more sail plan than 58 percent of similar sailboats, and that bias shows in the performance ratios: with the ISO reference sail the sail-area-to-displacement ratio is 16.8, rising to 19.7 with a 135 percent genoa, a configuration that makes her faster than 58 percent of similar designs in light wind. The theoretical hull speed is 6.4 knots and the relative speed performance puts her ahead of 42 percent of similar boats. Her motion comfort ratio of 21.3 beats 42 percent of comparable designs, and an immersion rate of 774 pounds per inch means she settles noticeably under load — relevant given the 5.25-to-5.55-foot draft that shifts with burden. Control lines follow a disciplined pattern: halyards for main, jib, and spinnaker all run 101 feet at 5/16 inch, sheets for jib and genoa are 29 feet at 3/8 inch, and the mainsheet is 73 feet at 3/8 inch.
Accommodations
The dimensional hints set the living envelope: the beamy 3.04 length-to-beam ratio and the moderate displacement suggest a compact but usable cabin volume for a 29-foot design, and the 26-gallon water capacity sets a realistic coastal-cruising range.
Known Issues
The only documented construction caveat is the home-completion path: because BK Marin also sold the Mamba 29 as a kit, individual boats may vary in build quality. The fin keel's iron option carries no cited corrosion note in the available material.
Refits and Ownership
Ownership considerations center on the keel choice and the rig. A lead-fin example starts from a higher ballast-quality baseline than an iron-fin hull, and the overrigged fractional setup rewards a clean genoa lead and careful halyard maintenance — all control lines are specified to known lengths and diameters, which simplifies replacement. The 8-horsepower Yanmar diesel gives a calculated maximum under power of 3.8 knots, adequate for marina maneuvering rather than passage making.
The Verdict
The Mamba 29 is a coherent small Scandinavian sloop: beamy for her length, stiff for her size, and quick in light air thanks to a slightly overrigged fractional rig. She is not an offshore boat by her own capsize-screening math, but as a sheltered-water racer-cruiser with a lead-keel option and a documented production run, she offers a predictable platform — provided the buyer verifies the build quality of any home-completed example.
Pros
- Ballast ratio of 44 percent, higher than 69 percent of similar designs
- Beamier than 54 percent of comparable boats at a 3.04 length-to-beam ratio
- Light-air speed ahead of 58 percent of similar designs with a 135 percent genoa
- Lead fin-keel option for durable ballast
Cons
- Capsize screening of 2.00 excludes her from ocean races
- Home-completion kits mean variable build quality
- Modest 3.8-knot maximum speed under power
