Great Barrier Express Sailboat Review, Specs, and Listings

Design Brief & Intent

The Great Barrier Express was engineered as an uncompromising high-speed commuter and coastal racer. In an era when most cruising catamarans were heavy, low-performance pocket-cruisers with massive, wind-catching bridge decks, Tennant opted for an open wing-deck configuration utilizing aluminum pipe crossbeams and a trampoline platform. This design choice eliminated aerodynamic drag, dramatically shed weight, and prevented the pounding associated with low bridge decks.

Accommodation on the GBE is minimalist, split entirely between the two narrow hulls. The interior joinery in original production models is basic, relying on molded fiberglass liners and lightweight timber trim designed strictly to save weight. Each hull offers a snug, dry single or tight double berth, minimal storage, and space for a portable stove or head. There is no central saloon; rather, life aboard is lived on the expansive trampoline or under a temporary tent. The design was intended for young, athletic sailors willing to trade standing headroom and domestic luxuries for raw velocity and the ability to beach the boat on any sandy spit.

Variations & Configurations

Throughout its decades-long production history, the GBE evolved across three distinct factory generations, alongside numerous home-built variations.

The early Mark I hulls were primarily home-built utilizing double-diagonal kauri timber or marine plywood skins. These early iterations featured a very short, low-profile cabin trunk, leaving the interior layout exceptionally cramped.

The Mark II served as the plug for the series GRP (glass reinforced plastic) production molds. This version featured a slightly taller, lengthened cabin trunk to provide sitting headroom over the berths, and a raised main beam to improve clearance under the trampoline platform. The companionway was also upgraded from a side-entry hatch to a fore-and-aft sliding hatch.

The Mark III, introduced in the 1990s, represented a significant modernizing leap. It featured a 300mm wider beam, a 500mm taller rig, and fuller bows created by inserting a wedge template into the forward hull section to combat the pitchpoling tendencies of the original narrow-bowed hulls. The Mark III also replaced the traditional underhung rudders with high-aspect vertical rudders mounted on stern brackets.

Sailing Performance & Handling

On the water, the GBE behaves more like a high-performance sports car than a cruising boat. The boat's displacement-to-length (D/L) ratio of 60.2 highlights its ultra-lightweight, low-drag hulls, which allow it to accelerate instantly in a puff. With a massive sail-area-to-displacement (SA/Disp) ratio of 36.9, the GBE is incredibly powered, capable of easily flying its windward hull in moderate breezes. Upwind performance is outstanding, courtesy of deep, efficient daggerboards that allow the boat to point aggressively.

Conversely, the boat's motion in a seaway is highly active. A comfort ratio of 3.32 indicates that the GBE offers virtually no dampening; it responds to every wave crest with a quick, lively motion that demands physical engagement from the helm and crew. Its high stability index (capsize ratio of 4.93, a standard multihull geometry metric) indicates immense static stability up to its flying threshold, but because the GBE can fly a hull, helmsmen must remain highly vigilant in gusty conditions. Downwind, the boat is an absolute rocket, easily reaching speeds of 18 to 20 knots under a spinnaker or gennaker.

Market Snapshot & Economics

The GBE occupies a highly unique, cult-classic niche on the brokerage market, particularly in New Zealand, Australia, and the Pacific. It commands a solid, highly stable value relative to its age, trading at a fraction of the cost of modern carbon-fiber trimarans while offering comparable performance. Because the design conforms to the Open 8.5 Class box rule, well-maintained and actively campaigned boats with updated sail wardrobes and carbon spars command a notable premium.

Buyers should expect the purchase price to be only the entry fee, as many of these boats have been raced hard for decades. Refit economics are highly favorable for DIY owners due to the boat's small scale—replacing a trampoline, painting the narrow hulls, or updating running rigging is significantly less expensive than on a larger catamaran.

Known Issues & Triage

The primary structural concern for any vintage GBE is the structural integrity of the hulls, particularly on early wood-epoxy models.

Freshwater Rot & Core Degradation: On older timber and cedar-strip boats, freshwater leaks around deck hardware, stanchions, and the chainplates frequently lead to localized rot. Standard triage requires stripping back the fiberglass skin, digging out damaged wood, and laminating new timber or foam core back into place with epoxy.
Mast Step Compression: The massive compression load from the high-aspect rig can crush the structural beam or deck area supporting the mast step. On many older GBEs, this structural member must be cut out and rebuilt with heavy structural glass or reinforced timbers.
Beam Attachment Fatigue: The aluminum pipe crossbeams transfer immense torsional stresses to the hulls. The bolt-on brackets and the hull areas surrounding the beam mounts are subject to stress cracking and fiberglass fatigue. Owners must inspect these connections for structural movement, elongated bolt holes, or delamination.

Modernization & Upgrades

Owners of older GBEs have embraced a wide array of modern upgrades to keep the boats competitive under Open 8.5 racing rules or to make them more manageable for coastal cruising.

Carbon Fiber Rigs: Upgrading from the heavy, original aluminum mast to a modern, rotating carbon wing-mast is a common high-end modification. This upgrade reduces weight aloft, dramatically lowering pitching moment and increasing safety margins downwind.
Cassette and Transom-Mounted Rudders: The original underhung rudders have largely been replaced with kick-up cassette rudders or vertical transom-mounted rudders. This protects the rudders in shingle beaching scenarios and improves steering authority at high speeds.
Dual Electrical Systems: To avoid running heavy, failure-prone wiring harnesses across the open trampoline platform, modern owners frequently install two completely independent, lightweight LiFePO4 battery banks—one in each hull—charged by small, dedicated solar panels.

The Verdict

The Great Barrier Express is a legendary, exhilarating design that bridges the gap between high-performance beach cats and weekend cruisers. It is not a boat for those seeking comfort, standing headroom, or a passive cruising experience. Instead, it is a pure sailor's machine, offering explosive speed, finger-tip control, and a passionate community of active racers.

Pros

Blistering speed and superb upwind pointing ability.
Active, competitive, and supportive one-design and box-rule racing fleets.
Demountable configuration allows for easier overland transport or dry-dock storage.
Extremely affordable path to high-performance multihull sailing.
Beachable design allows for easy exploration of shallow anchorages.