• xaptain's chair,
• vaptain's chair,
• faptain's chair,
• daptain's chair,
• czptain's chair,
• csptain's chair,
• cwptain's chair,
• cqptain's chair,
• caotain's chair,
• caltain's chair,
• ca-tain's chair,
• ca0tain's chair,
• caprain's chair,
• capfain's chair,
• capgain's chair,
• capyain's chair,
• cap6ain's chair,
• cap5ain's chair,
• captzin's chair,
• captsin's chair

The adjective form of the phrase "captain's chair" would be "captain's".