Endurance adapted to an age-of-sail combat role

How could Endurance be adapted into an age-of-sail warship?

Her strong hull could make her useful as a mortar ship, while her general utility would resemble that of a collier.

The question places the 1912 Endurance, with her sturdy hull and 10-knot steam speed, in an age-of-sail setting. A mortar ship is the preferred combat role because of the hull's strength. Her general utility is also compared with a collier.