Nacra 5.5 Sloop Information, Review, Specs

The 5.5 series was produced in two primary configurations: the 5.5 Sloop, which utilizes a mainsail and jib for a two-person crew, and the 5.5 Uni (or Cat-rigged), which features a larger, taller mainsail designed for solo sailors. Both variants were built on the same high-performance hull, but the Sloop variant remains the most popular for those seeking a collaborative racing experience. While the standard boat features an 8.5-foot beam—making it legally trailerable without special permits—the design's focus on power and leverage set a new standard for 18-foot catamarans in the late 1980s and early 1990s.

Sailing Performance & Handling

The sailing characteristics of the Nacra 5.5 Sloop are defined by its exceptional power-to-weight ratio and its use of deep daggerboards. Unlike the skeg-hulled Nacra 5.0 or 5.7, which were designed for easier beaching and recreational use, the 5.5's daggerboards allow for superior upwind pointing angles and surgical precision during tacks. Owners often report that the boat "finds its groove" quickly, with a sensitive helm that rewards active sail trimming.

In heavy air, the 5.5 Sloop is a physical boat to sail. The tall rig generates significant righting moment, requiring the crew to spend a great deal of time on the wire (trapeze). Because of the hull’s increased volume compared to older designs, the boat handles the "wild thing" (flying a hull downwind) with more stability than the 5.2. Technical reviews from the era often noted that the boat’s ability to "slice" through chop rather than hobby-horsing over it was a direct result of the refined Morrelli & Melvin hull geometry. The absence of a traditional boom on many 5.5 setups (boomless rig) also improves safety during gybes, though it requires a high-tension mainsheet system to maintain proper sail shape.

Popular Mentions & Media

While the Nacra 5.5 Sloop does not have a single "famous" owner in the celebrity sense, it holds a prestigious place in the history of the Formula 18 Class. It is widely regarded by marine historians as one of the direct ancestors of the modern F18 racing machines. The lessons learned from the 5.5’s hull volume and sail plan directly informed the development of the Nacra Inter 18 and later the Nacra F18. Its cultural footprint is most visible in the archives of long-distance catamaran races like the Tybee 500 or the Worrell 1000, where Nacra 5.5s were frequently utilized as reliable, high-speed platforms for endurance racing.

Known Issues & Buyer’s Checklist

For prospective buyers, the Nacra 5.5 Sloop is a durable boat, but it has specific areas that require scrutiny due to its age and the high loads it carries:

• Daggerboard Trunks: The most critical area for inspection is the junction where the daggerboard trunks meet the hull. High-speed grounding or heavy racing stress can lead to stress cracks or leaks in the trunk seals.
• Deck Softness: Like many sandwich-constructed fiberglass boats of its era, "soft spots" can develop on the decks, particularly in the areas where the crew stands or sits while on the trapeze. This usually indicates delamination of the core and requires professional repair to restore structural integrity.
• The "Nacra Hum": Some 5.5s suffer from a vibration in the rudders at high speeds. This is often caused by the trailing edge of the rudders being too blunt or asymmetrical. While not a structural failure, it can be a nuisance and is usually fixed by carefully sanding the rudder edges to a fine taper.
• Mast Step and Dolphin Striker: Ensure the dolphin striker (the cable and post system under the main beam) is under proper tension. If this system is loose, the main beam can flex excessively, leading to hull misalignment or catastrophic failure of the mast step.

Community & Resources

The primary hub for technical support and class history is the International Nacra Class Association. While the 5.5 is no longer in active production, having been superseded by the F18 and Nacra 17 Olympic classes, the association maintains a repository of technical manuals and rigging guides. For parts and specialized hardware, many owners still rely on the original manufacturer, Nacra Sailing, which continues to provide support for its legacy fleet through its global dealer network.

The Verdict

The Nacra 5.5 Sloop is a masterclass in transitional multihull design, offering a "pure" sailing experience that remains competitive even against modern designs. It is a boat for the serious enthusiast who values technical feedback and raw speed over casual cruising.

• Pros:
  • Exceptional upwind performance thanks to deep daggerboards.
  • High-volume hulls provide better pitch-pole resistance than vintage cats.
  • Strong resale value and a dedicated enthusiast community.
  • Versatile enough for both buoy racing and long-distance coastal hops.
• Cons:
  • Physical demands require a reasonably fit crew for high-wind sailing.
  • Daggerboard trunks require careful maintenance compared to skeg-hull models.
  • Rigging is more complex than contemporary "recreational" catamarans.