Design and Construction
Van de Stadt gave the Seal 36 a true flush deck, raising the hull topsides to a height that yields standing headroom below without resorting to a long coach-roof anchor. The result is a sturdy yacht with a lot of usable deck area and a compact form that still manages a large footprint both on and below deck. Her high freeboard is a deliberate seakeeping choice: it keeps less water coming aboard in rough going anchor. Built as a fin-keel, masthead-rigged monohull, the steel version displaces about 9.25 tonnes with 3.30 tonnes of ballast, while aluminum and wood versions are lighter at 8.25 tonnes, carrying 3.50 and 3.60 tonnes of ballast respectively anchor. That places her firmly among what one review describes as "ultra heavy cruisers" on the displacement-length scale anchor, with a ballast ratio near 36 percent and a length-to-beam ratio of 3.11.
Rig and Handling
The Seal 36 is built with a masthead rig and carries a modest sail plan — about 79 square meters under sloop or cutter rig, 82 as a ketch anchor. A review notes she has more rig than only 31 percent of similar sailboats, leaving her slightly underrigged on paper anchor, and the sail-area-to-displacement figures bear this out: 13.4 with the reference sail, rising to 16.2 with a 135 percent genoa anchor. Her theoretical hull speed sits near 7.2 knots, and the capsize screening value of 1.70 places her in conventionally accepted offshore territory anchor. The motion comfort ratio of 38.8 and an immersion rate around 1,155 pounds per inch describe a boat that rides quietly and resists being pushed around by seas rather than one that leaps to weather.
Accommodations
Below, the Seal 36 is roomy for her length, with a completely separate aft cabin reached safely below deck — a layout feature that appeals to couples and long-term cruisers anchor. The flush-deck hull height gives standing room without a protruding cabin trunk, though one review measured headroom as below average for the class anchor. The compact exterior belies a large interior area, and the separation of the aft cabin from the main saloon is a genuine privacy asset on a 36-foot hull.
Known Issues
The only cautions are intrinsic to her design: the deep fin keel means a draft around 1.90 to 2.00 meters depending on load, limiting her to major marinas anchor, and her below-average headroom is a accommodation trade-off rather than a defect.
Refits and Ownership
Because the Seal 36 was typically custom-constructed or yard-built in multiple materials, ownership experience varies with the builder's chosen medium. Steel versions carry the most 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 a buyer who values a separate aft cabin, a dry flush deck, and heavy-displacement steadiness over speed or airy headroom.
Pros
- True flush deck with standing headroom and large deck area
- Separate, safely reached aft cabin on a 36-foot hull
- High freeboard keeps water off the deck in rough weather
- Capsize screening and comfort ratios suit extended cruising
Cons
- Below-average headroom below deck
- Deep fin keel restricts her to deeper marinas
- Slightly underrigged relative to similar sailboats
