Heating a sailcraft

This almost-past winter I have been collecting statistical data related to heating a sailboat in cold weather. For the experiment I am using a high performance Phase Change Heating System driven by electricity. The final goal is to support the electrical load of the system during winter time with renewable energy harvested from the sailboat. This should be one of the core life support systems in Project 105 over cold periods. So far, the data is encouraging, however, for Northern climates, additional heat sources are probably required.