BATH – Bath Iron Works said Wednesday it plans to lay off up to 70 designers, effective March 1, because of a lack of ship design work in Navy programs.

Shipyard spokeswoman Susan Pierter said the layoffs are considered permanent. The exact number of employees who will lose their jobs has not been determined, but the total will not exceed 70.

The designers are represented by the Bath Marine Draftsmen Association, the shipyard’s second-largest union.

“I find it horrifying,” union president Mary Cunningham said of the upcoming layoffs. She said the affected workers help with the design of destroyers, publications and handle design changes to ships under production.

Thirty-five union members, including 26 designers, were laid off in December for lack of work. The shipyard currently employs about 6,700, including 687 members of the draftsmen’s union.