Perry Design Review: Nelson/Marek 46 IMS

Carroll Marine and Nelson/Marek have teamed up again to build this hot rod 46-footer designed to compete under either the ILC 46 class or straight IMS. The Nelson/Marek office is responsible for a large number of dominant IMS boats racing across the country. I find its designs to be as stylish and handsome as they are effective on the race course. Barry Carroll's efforts as a builder of beautifully detailed high-tech racing yachts have made him equally as dominant in the field. Don't be embarrassed if you find yourself drooling as you stand on the dock looking over one of these boats.

The 46 weighs 18,500 pounds and has 11,000 pounds of ballast in a deep, high-aspect-ratio fin. The result is a ballast-to-displacement ratio of 59 percent and lots of stability to carry the big sail plan. This is enhanced by filling out the stern for additional power. The entry is fine, and the midsection shows no deadrise anywhere. Looking at a big IMS hull recently, I was struck by the ultimate fairness of the lines. The shapes are so smooth and free of a transition area that they are almost boring, while achieving the definition of slipperiness. The D/L of this design is 139 and L/B is 3.42.

Note the saildrive unit on the Volvo 50-horsepower diesel. It integrates prop shaft and strut into one clean unit that has less drag than a conventional shaft, bracket and prop installation. The IMS also looks favorably on the saildrive for rating purposes, but that may change soon. Builders like saildrives because they are very simple to install. Designers like them for their additional advantage of compressing the weights into the middle of the boat, which also places the saildrive unit in the wash of the keel where its drag will be minimized.

IMS interiors have been gravitating to a basically standard format over the last few years. The idea, as always, is to satisfy the rule while not slowing the boat down. This means that interiors are minimal with all weights centered. From a cruiser's point of view, these boats may not have a decent interior, but you might be surprised at just how attractive they can be. Nelson/Marek's styling approach and Barry Carroll's execution of it make these boats attractively businesslike below. The interior uses vacuum-molded components integrated with the structural system to contribute to the overall stiffness of the hull.

With an SA/D ratio of 27.33, the Nelson/Marek 46 is not radical in terms of horsepower, but it is far from moderate. Consider that in the early days of the IOR, a big SA/D ratio was usually around 18.5 to 20. IMS has given us very manageable hulls that can carry big rigs with no control problems. There are four spreaders on this rig along with runners, checkstays and short jumpers at the hounds. The roach overlaps the backstay by about six inches.

There are no surprises in the deck layout. The cockpit is huge and open to the transom. Mainsail controls are led port and starboard to consoles that allow adjustments to main shape to be made from the weather side. Minimal headsail changes, a function of the fractional rig, mean that you don't need a huge foredeck hatch. Steering is through Edson's new Spectra line-and-spool system for light weight and sensitivity.

A fast design you'll want to take around the course.

Boat Specifications

This story originally appeared in Sailing Magazine, and is republished here by permission. Subscribe to Sailing.