NEW YORK—Christopher Duca has been named president and chief executive officer of Navigators Management Co. Inc., specialty insurer Navigators Group Inc. said Friday.

Mr. Duca was named President and CEO of Navigators Management Co. Inc. Stan Galanski remains CEO of The Navigators Group Inc. and will also continue to serve as the chairman of NMC.

Additionally, NMC has promoted Michael Civisca to executive vp and chief operating officer. Previously, he was responsible for NMC's marine, energy, inland marine and commercial multiperil business.

Ed Helfers, who formed NMC's inland marine unit in 2006, has been named president of NMC's marine division and will continue to manage the unit.

Lori Ann Lowery, who most recently was president of Lloyd's Inc., North America, has joined Navigators in the new post of president of field operations. Ms. Lowery has held several executive positions with Wells Fargo Insurance Services and Marsh & McLennan Cos. Inc. She will oversee NMC's marketing, sales and distribution management and have overall oversight of U.S. regional management.