Design and Construction
Van de Stadt gave the Seal 36 a true flush deck, raising the hull topsides enough to provide standing headroom below without a long coachroof. This creates plenty of usable deck space and a compact overall form with a large footprint both on deck and below.
Her high freeboard is a deliberate seakeeping choice, intended to reduce the amount of water coming aboard in rough conditions anchor. The Seal 36 is a fin-keel, masthead-rigged monohull offered in three construction materials. The steel version displaces about 9.25 tonnes and carries 3.30 tonnes of ballast. Aluminum and wood versions are lighter at 8.25 tonnes, with 3.50 and 3.60 tonnes of ballast respectively.
One review places her among “ultra heavy cruisers” on the displacement-length scale anchor. Her ballast ratio is near 36 percent, and her length-to-beam ratio is 3.11.
Rig, Performance, and Handling
The Seal 36 has a masthead rig and a modest sail plan: about 79 square meters under sloop or cutter rig, or 82 as a ketch. One review notes that she carries more rig than only 31 percent of similar sailboats, leaving her slightly underrigged on paper anchor. The sail-area-to-displacement figures support that assessment: 13.4 with the reference sail, rising to 16.2 with a 135 percent genoa anchor.
Her theoretical hull speed is near 7.2 knots. A capsize screening value of 1.70 places her in conventionally accepted offshore territory anchor. Her motion comfort ratio is 38.8, while an immersion rate of around 1,155 pounds per inch describes a boat that rides quietly and resists being pushed around by the sea rather than one that leaps to weather.
Accommodations
The Seal 36 is roomy for her length. A completely separate aft cabin, reached safely below deck, is a particularly useful feature for couples and long-term cruisers. On a 36-foot hull, separating the aft cabin from the main saloon provides genuine privacy.
The flush-deck hull gives standing room without a protruding cabin trunk. Even so, one review measured the headroom as below average for the class anchor. The compact exterior nevertheless contains a large interior area.
Draft and Other Trade-Offs
The design’s main cautions are intrinsic rather than reported faults. Its deep fin keel gives a draft of around 1.90 to 2.00 meters, depending on load, limiting the boat to major marinas. Below-average headroom is an accommodation trade-off rather than a defect.
Refits and Ownership
Because Seal 36s were typically custom-built or yard-built in several materials, the ownership experience varies with the builder and chosen construction medium. Steel versions have the highest displacement and the lowest ballast-to-displacement figure. Wood and aluminum versions are lighter but carry more lead.
The flush deck and separate aft cabin reward careful upkeep of deck penetrations, but no widespread failure points are described.
The Verdict
The Seal 36 is a thoughtfully drawn van de Stadt cruiser that trades sparkling performance for volume, security, and offshore-acceptable stability. She suits buyers who value a separate aft cabin, a dry flush deck, and heavy-displacement steadiness more than speed or airy headroom.
Pros
- True flush deck with standing headroom and plenty of usable deck area
- Separate aft cabin, reached safely below deck, on a 36-foot hull
- High freeboard helps keep water off the deck in rough weather
- Capsize screening and comfort ratios suited to extended cruising
Cons
- Below-average headroom below deck
- Deep fin keel restricts access to deeper marinas
- Slightly underrigged relative to similar sailboats
