Design and Intent
The 46 was drawn as a pure instrument of measurement-system racing. Her IMS hull shapes are smooth and free of any transition area, almost boring in their fairness, with a fine entry and a midsection showing no deadrise anywhere. Stability to carry the big sail plan comes from the deep fin and is enhanced by filling out the stern for additional power. A D/L of 139 and an L/B of 3.42 place her firmly in the light-displacement, beamy racer category, while the 39-foot-3-inch waterline and 9-foot-2-inch draft speak to a boat optimized for reaching and running under rule-driven constraints. The Nelson/Marek office behind her had already produced a large number of dominant IMS boats racing across the country, and this 46 is very much in that lineage.
Construction
Carroll Marine built the 46 in fiberglass and Kevlar, with solid fiberglass hull and deck and a lead-ballasted fin. Interior components were vacuum-molded and integrated with the structural system so that they contribute to the overall stiffness of the hull rather than merely furnishing it vacuum-molded components integrated with structure. Weights throughout are centered to satisfy the IMS rule while not slowing the boat down, which is why the interior is minimal. This is a structure built to be stiff and light first, habitable second.
Rig and Handling
The rig is a masthead sloop with four spreaders, runners, checkstays, and short jumpers at the hounds — a thoroughbred arrangement that demands attentive tuning. The fractional-style headsail setup minimizes headsail changes and removes the need for a huge foredeck hatch. The mainsail roach overlaps the backstay by about six inches, and mainsail controls are led port and starboard to consoles that let the crew adjust main shape from the weather side. A huge, open cockpit running to the transom gives the trimmer room to work, and steering runs through Edson's Spectra line-and-spool system for light weight and sensitivity. Under power, a Volvo 50-horsepower diesel drives a saildrive unit that integrates prop shaft and strut into one clean assembly, compressing weight into the middle of the boat and sitting in the wash of the keel to minimize drag compared with a conventional shaft, bracket, and prop.
Accommodations
As noted, the interior is minimal by any cruising standard. All weights are centered, and the vacuum-molded components serve structure before creature comfort. There is 40 gallons of water and 20 gallons of fuel — figures that confirm the boat's race-first priorities rather than any offshore-autonomy ambition. A buyer expecting a roomy cruiser's layout will find instead a spartan shell dressed to make sail and win under rating.
The Verdict
The Nelson Marek 46 is a focused IMS weapon: light, stiff, and beautifully fair, with a deep fin and centered weights that let her carry a generous sail plan without apology. She is not a cruiser with racing pretensions but a racer with just enough interior to be legal. For the right owner — one who values rating-correct speed and structural honesty over galley count — she remains a clean, purposeful 46-foot hot rod.
Pros
- Deep, high-aspect fin with 59 percent ballast ratio for strong stability
- Vacuum-molded interior integrated into a stiff, light structure
- Saildrive in the keel wash reduces drag versus conventional shaft
Cons
- Minimal interior with only 20 gallons fuel and 40 gallons water
- Four-spreader rig with runners and checkstays demands constant tuning attention
