But when a customer wanted the benefits of one-piece fiberglass along with the beauty of perimeter-overflow, it didn’t occur to Marshall Knight to worry — even though he had never heard of such a pool being built.

“There was no reason why I couldn’t do it,” says the owner/operator of Bahamas Pool & Patio Ltd. in Nassau, New Providence, Bahamas. “The only difference between my pool and a regular pool is the gutter system itself. I know that there’s a logical way to figure this stuff out.”

Like the two other fiberglass-pool mavericks discussed here, Knight was aware that there would be some concerns specific to building a perimeter overflow using a one-piece fiberglass vessel.

There are three basic challenges to this type of installation: Leveling the edge, crafting the gutter, and preventing leaks.

• Leveling the edge: The perimeter of any four-sided vanishing edge must be as close to level as possible — most concrete builders try to work within 1/16- to 1/32-inch tolerances.

With concrete, if the initial shooting isn’t absolutely precise, the crew can grind and float the top until everything falls within the desired tolerance. But fiberglass doesn’t offer that luxury. A gigantic shell must be leveled, and every little nudge on one area will tweak another part of the pool out of alignment.

• Crafting the gutter: For concrete builders, shooting or pouring the gutters is just a more advanced version of what they already do. Additionally, this component is built as part of the overall shell. But fiberglass installers must find a way to attach a gutter system to the shell.

• Preventing leaks: With the shell and gutter systems being separate entities, the builders need to prevent water from leaking as it transitions out of the pool.