Design and Construction
Primrose gave the Seal 28 a solid fibreglass hull and a drop keel that lifts and lowers vertically, a configuration the builder listed at roughly 2.5 to 2.8 feet of draft dependent on load lifting keel behavior. The keel is iron-ballasted at 2,900 pounds against a 7,200-pound displacement, a 40-percent ballast ratio. At 9.83 feet of beam on a 28-foot length she shows a length-to-beam ratio of 2.82. The wetted surface runs about 258 square feet, and the immersion rate of 952 pounds per inch tells you she sits heavily for her size.
Rig and Handling
She is a masthead sloop carrying 310 square feet of sail, and the sail-area-to-displacement ratio of 12.21 places her in the moderate, forgiving band. The running rigging follows period masthead convention: jib and genoa sheets of 27.8 feet at 3/8 inch, a 69.4-foot mainsheet of the same diameter, and spinnaker sheets of 61.1 feet rig dimensions. The lifting keel gives her a shallow-draft mode for exploring. Her capsize screening value of 2.04 is below the threshold accepted for ocean racing, confirming her theater as coastal cruising.
Accommodations
Below, the Seal 28 is laid out with three cabins and six berths, a galley, and a toilet facility. That berth count in 28 feet makes her a genuine pocket cruiser rather than a dayboat with berths bolted in.
Known Issues
The lifting keel is the structural weak point by design. A vertically raising drop keel demands a trunk, pivot, and sealing arrangement that a fixed-keel boat does not have, and on a 28-footer those areas are where water intrusion and wear concentrate. The 258-square-foot wetted surface and 952-pounds-per-inch immersion mean she loads deeply with cruising gear, stressing the keel trunk and hull-deck joint as the boat works in a seaway.
Refits and Ownership
Ownership means living with a lifting keel that needs periodic inspection and likely rebedding of its trunk, and with a rig whose sheet lengths are known and reproducible if renewal is needed. The iron ballast is simple and cheap to live with compared with lead. With only 80 built, she is a comparatively rare Primrose design.
The Verdict
The Seal 28 is a thoughtfully proportioned small cruiser offering genuine cabin accommodation and a lifting keel for flexible cruising. She is not an offshore racer, but a beamy pocket cruiser with the ballast to feel like a boat.
Pros
- Three cabins and six berths in 28 feet make her a real cruiser
- 40-percent ballast ratio and iron keel give reassuring stability
- Lifting keel expands shallow-water capability
Cons
- Capsize screening of 2.04 excludes her from ocean racing
- Lifting-keel trunk is an inherent maintenance and sealing liability
- Only 80 built, so good examples are uncommon
