Changes

The HVAC system uses a blend of loosely coupled systems to provide maximum energy efficiency and redundancy for a year-round live-aboard. Fresh-air ventilation uses small zone-based air vents but this makes humidity control difficult. The heating and cooling systems use a shared circulating-water distribution system to minimise bulkhead pass-throughs. Heating is by a diesel furnace with backup from a diesel fireplace. Cooling is by a chiller with keel cooler, with backup from the cold-plate refrigeration system. Hot water is heated by the engine, the diesel oven, a [https://en.wikipedia.org/wiki/Solar_thermal_collector solar collector ] or AC elements using shore power or the house bank.

But what happens in an emergency? In the event the furnace fails, the Bristol Pacific model diesel stove in the galley can provide 6,500-16,250 BTU to heat the forward accommodation. At the lower heat setting it could maintain a temperature differential of 21 C°C, while the higher one maintains the design differential requirement of 55 C °C in the forward compartment.

At the lower setting, water pipes, etc., are protected down to -20 C°C, a not infrequent winter temperature, which is why the design requirement is the higher 55 C °C differential. Because the galley stove alone cannot heat the whole boat in the event of a furnace failure, additional heat has to be supplied by the diesel fireplace in the salon. A fireplace such as the Bubble produces only 3.5 kW (11,946 BTU), good for a 17 C °C differential overall. So it will only heat the pilothouse and salon, not the aft cabin.