I'm not sure it would even be allowed.
https://www.carnival.com/help?topicid=1202
Electrical and household appliances containing any kind of heating element, such as irons, clothes steamers, immersion heaters, heating blankets, water heaters, coffee machines, hot plates, toasters, heating pads, humidifier, etc. (All Carnival ships provide facilities with ironing boards and irons; fleet-wide valet laundry service is also available for a nominal fee.)