The land-use and zoning committee of Community Board 5 voted last night, 6 to 4, to recommend that the City Planning Commission disapprove the granting of a special permit to allow residential development and a waiver of height, setback and rear-yard requirements for a very unusually shaped, 21-story residential tower at 39 West 23rd Street in the Ladies' Mile Historic District planned by Horizen Global LLC, of which Michael Yanko is chief executive officer,

The development's design by Carlos Zapata Studio and Gruzen Samton LLP has been approved by the Landmarks Preservation Commission, but is now in the city's Uniform Land Use Preview Process (ULURP). The commission requested that the design be modified by reducing its height by a few stories and it required the developer to restore and promise to retain the facades of the existing low-rise residential building at 37 West 23rd Street.

The design calls for a white-glass-clad, narrow tower that not only slants to the north above its-low rise base on 23rd Street, but also cantilevers over its rear yard and also slightly over an adjoining low-rise residential building that is part of its zoning lot to the east at 37 West 23rd Street.

The "whittled" design is not simple and there are a variety of other facets, and a few notches, to its facades.

The project would have retail on the ground floor and residential condominium apartments above. Mr. Zapata told the committee last night that the number of units has not yet been finally determined and would be between about 44 and 76 although as-of-right zoning for the site permits about 110.

The site runs through to 24th Street where a three-and-a-half-story, single-family townhouse would be erected as part of the development.

The project's chamfered design also is somewhat similar in concept to One Bryant Park, the much larger skyscraper being erected now on the northwest corner of 42nd Street and the Avenue of the Americas.

Mr. Zapata's and Mr. Samton's design, however, follows the strange logic of the city's zoning and building regulations and, as a result, represents an extremely intriguing and formidably sculptural form, especially for New York above the clean-cut lines of its low-rise base.

The committee had some trouble grappling with the project's design complexities, leading Meile Rockefeller, co-chairperson of the committee, to gently ask Frank Angelino, a spokesman for the developer, "Can you give a compelling reason why you want to do this?"

Mr. Zapata explained that this design seeks to "maximize air and light" and that a taller building that conformed to existing regulations would provide less usable square footage and cast longer shadows.

The tower of the mid-block building would be quite narrow with only about 3,500 square feet on a floor. It would be a few stories higher than the tall buildings at either end of the block but its slanted design would more views of the Metropolitan Life clocktower building on Madison Avenue as seen from the Avenue of the Americas than a sheer tower, Mr. Zapata said.

The top of the low-rise base on 23rd Streets projects out about 22 inches to "look like a cornice," he said.

The building would replace a 96-car parking lot.

Several members of the committee expressed concerns that this relatively small project could be "the tipping point" that could "become the underlying justification" for a residential rezoning of the neighborhood, noting that many of the commercial buildings around Madison Square Park to the east are being converted to residential uses at the same time as new residential construction is transforming the former flower district along the Avenue of the Americas.

"We're trying to stem the pressure of residential development," one committee member said.

Horizen Global's other Manhattan projects include Hudson Blue at 423 West Street.