Use AutoHotkey (AHK) to record yourself building one side of a symmetrical boat, then mirror it. This is technically not a script (it just mimics keyboard/mouse) and has a lower ban risk.
Auto-building scripts in Build A Boat For Treasure are popular tools for automating complex ship designs or converting images into in-game structures. This guide outlines how these scripts typically function and the necessary precautions when using them. Core Script Features Build A Boat For Treasure Auto Build Script