For more than two decades, the 5.8 has been Australia’s largest one-design big-boat class. It’s a true racing machine, not a cruiser with racing pretensions: the entire specification is intended to be pushed hard in windy water.
Design and Construction
The 5.8’s white hulls are moulded in foam-sandwich vinylester, with solid fiberglass used elsewhere. Their large volume allows the boat to be driven hard after lesser catamarans have had to back off.
Above the waterline, non-skid decks, round cross beams, and a grey mesh trampoline complete the platform. Carbon-reinforced rudders and daggerboards reflect the loads generated by a racing dinghy-cat.
According to Multihulls World, the boat weighs 407 pounds. With an 8-foot beam and a 19-foot overall length, it is light and narrow enough to be trailable, yet stable enough for double-trapeze sailing.
Rig and Handling
Seaman’s rig centers on an exclusive bridle foil system. This allows the jib to be larger but set lower, reducing heeling motion and helping the boat stay flat and fast.
Anodised spars, coated shrouds, a captive mast-ball system, and adjustable wing-shaped spreaders with Sta-master diamond-wire adjusters provide precise mast control. Mast-spanner controls, a 10-1 main downhaul, and a 3-1 jib-luff system allow the crew to tune and depower the rig in all conditions.
The sail plan pairs a new Pentax square-top mainsail with a vertical-cut racing Dacron jib and racing battens. Period specifications also list a Harken mainsheet system and traveller, a Barber hauler, and a double trapeze.
Even when depowered, the boat is very easy to control. That reflects the positive Ackerman steering and adjustable kick-up rudders as much as the balance created by the bridle foil.
Cockpit and Accommodations
There are no accommodations in the cruising sense. The grey mesh trampoline spans the cross beams, while the hulls provide volume rather than cabins. Every listed feature—from the traveller and trapeze to the diamond wires—serves speed. Anyone considering a 5.8 for liveaboard space has misunderstood the design entirely.
Known Issues
The available material identifies no structural defect, systemic failure, or class-wide weakness. A manufacturer’s note on standard features and safety cuts off before detailing any safety equipment, so no statement can be made about emergency gear.
The sources do establish that the boat has carbon-reinforced rudders and daggerboards, along with adjustable kick-up rudders. Wear in these components would be a concern when assessing a used boat, but the available material doesn’t describe their failure modes.
Refits and Ownership
Ownership is straightforward in the manner of a trailable one-design racer. The sail plan is built around tunable, replaceable elements, including the square-top mainsail, vertical-cut jib, and diamond wires. The bridle foil and Harken hardware are standard-class items.
Roy Seaman’s plugs for this model line date from 1985 onward. That places the 5.8 in Nacra’s early hand-laminated generation rather than the later vacuum-infused, foam-core era, which began with the F18 Infusion in 2006.
The Verdict
The Nacra 5.8 is a purpose-built racing catamaran with a long one-design history in Australia and a rig engineered to deliver controllable power. Its large-volume hulls and bridle foil make it forgiving at speed, while its tunable deck hardware suits the serious club racer.
Pros
- Large-volume, foam-sandwich hulls that sustain pace in heavy air
- Bridle-foil rig that reduces heeling and makes the boat easier to control
- Fully tunable rig with a Harken mainsheet system and diamond-wire adjustment
Cons
- No cruising accommodations of any kind
- Earlier hand-laminated construction rather than the later infused build
- No safety-equipment inventory beyond the incomplete specification note
