Why a small corvette suited a worldwide survey

A small vessel was cheaper to support and imposed less strain on the Royal Navy's fighting strength than a larger conversion. A cruiser would have offered more scientific space, but it would also have required more money and crew while removing a more valuable combatant from normal duties. Corvettes, sloops, and gunboats were already familiar sights across Britain's overseas stations. Challenger could visit many ports as a low-profile presence vessel without attracting the attention that a conspicuous major warship might draw.