Azure’s Onboard Power System

Azure offers a quieter, greener and more considered way to cruise the Ionian.

As the flagship of our bareboat fleet, she has been designed to operate without a diesel generator, using a high-capacity battery bank, solar power and intelligent charging instead.

The result is a more peaceful atmosphere on board, especially at night, without the noise, vibration and environmental impact that generators can bring to quiet anchorages. It is a slightly different approach to onboard comfort, but one that many guests quickly come to appreciate.

Executive Summary

• Set air conditioning to around 24°C and keep cabins closed for the best overnight performance.
• Pre-cool cabins for 10 to 15 minutes before sleep rather than running the system on maximum for long periods.
• Do not leave air conditioning running when the yacht is unoccupied.
• Use energy overnight and recharge during the day.
• Check the battery monitor and plan ahead, as small adjustments make a big difference.

How Azure's Systems Operate

The system works around a simple daily rhythm: energy is recharged during the day through solar, engine use and shore power when available, then used overnight for onboard comfort, including air conditioning. In practice, the key principle is simple: use energy overnight, recharge during the day.

Air conditioning on Azure is designed primarily for overnight comfort and, when used sensibly, performs very well. Running all cabin units at moderate settings will typically provide around 8 to 10 hours of cooling overnight, and setting the temperature to around 24°C rather than lower settings can significantly reduce energy use and extend runtime.

During the day, air conditioning can also be used, provided consumption is balanced with charging. For example, if only the saloon air conditioning is running and battery levels are already healthy, solar power will often still allow the batteries to continue charging.

When shore power is available in marinas, it allows for near-unrestricted use of air conditioning, provided the batteries are at a reasonable level to begin with, typically above 40 percent. However, shore power in many Greek harbours can be limited, shared or unreliable, which is why Azure is designed to operate comfortably without depending on it.

To protect battery reserves overnight, the system automatically manages load in stages if battery levels begin to fall. The saloon air conditioning switches off first, then the aft cabin, and finally the bow cabin, helping to prioritise cooling in the sleeping cabins and preserve battery health for the following day.

Azure is also equipped with low-power cabin fans for improved airflow and highly efficient refrigeration, which can be used almost without limitation.

Overall performance may still vary slightly depending on solar energy levels, ambient temperature and your cruising plans, but with a little planning guests typically enjoy smooth day-to-day operation and reliable overnight comfort throughout their charter.

If you have any questions before you arrive, we are always happy to help, and if you have a skipper or host on board they will also monitor the system and guide you as needed.

Golden Rules:

• Set the air conditioning to around 24°C and keep cabins closed to achieve the best overnight comfort.
• Cool cabins briefly before bedtime rather than running the system at maximum for extended periods.
• Please avoid leaving the air conditioning on when the yacht is unoccupied.
• Use stored power overnight and allow the system to recharge during the day.
• Keep an eye on the battery monitor and plan ahead, as small changes can make a noticeable difference.

FAQ

What makes Azure different from other charter yachts?

Azure has been designed to operate without a diesel generator, using advanced batteries, solar power and intelligent charging instead. This creates a quieter, cleaner and more peaceful onboard experience, particularly at night and in quiet anchorages.

Why doesn’t Azure have a generator?

At Sail Ionian, the decision not to rely on a generator was a conscious one. Generators are common on many yachts, but they can be noisy, intrusive to guests and neighbouring boats, and less in keeping with the natural environment we cruise through in the Ionian.

How does the power system work?

The system follows a natural daily cycle. During the day, batteries recharge through solar power, engine use and shore power when available; at night, that stored energy is used for onboard comfort, including air conditioning.

Can we rely on shore power in marinas?

Shore power is helpful when available and can allow near-unrestricted air conditioning use if battery levels are already reasonable, usually above 40 percent. However, in many Greek harbours the supply can be limited, shared or unreliable, so Azure is designed to operate comfortably without depending on it.

How long will the air conditioning run overnight?

In normal real-world use, running all cabin air conditioning units at moderate settings will typically provide around 8 to 10 hours of cooling overnight. Exact runtime can vary depending on battery levels, outside temperature and how the system is used.

What temperature should we set the air conditioning to?

Around 24°C is ideal. Lower settings such as 22°C use significantly more energy and can reduce runtime without necessarily making the cabins feel more comfortable overnight.

What is the best way to use the air conditioning at night?

For best performance, pre-cool cabins for 10 to 15 minutes before sleep, keep doors, hatches and windows closed while the air conditioning is running, and avoid leaving it on when the yacht is unoccupied. These simple habits help the system run far more efficiently.

Can we use air conditioning during the day?

Yes, absolutely. The main aim is simply to balance usage with charging, so that you are not using more energy than the yacht is generating. If only the saloon air conditioning is in use, solar power alone will often still allow the batteries to continue charging, especially if the day starts with a healthy battery level.

What happens if battery levels drop overnight?

The system automatically protects itself by reducing load in stages. The saloon air conditioning switches off first, then the aft cabin, and finally the bow cabin, which helps prioritise cooling in the sleeping cabins and extend runtime as much as possible.

Are there other comfort features on board?

Yes. Azure is fitted with low-power cabin fans to improve airflow and comfort with very little energy use, and her refrigeration system is highly efficient and can be used almost without limitation.

What if we want unrestricted overnight air conditioning?

If full, unrestricted overnight air conditioning is a priority, it is worth planning occasional nights on shore power. Otherwise, many guests prefer to stay off-grid and take a slightly more energy-conscious approach throughout the trip.

How should we plan our power use during the week?

The best approach is to monitor battery levels, plan ahead and make small adjustments as needed. If the next day is likely to involve light winds and more motoring, batteries can usually be allowed to run slightly lower overnight because they will recover more quickly; on sailing-heavy days with less engine use, it is better to be a little more conservative.

Are there any variables that affect performance?

Yes. As with any onboard energy system, performance can be influenced by solar energy levels, ambient air temperature and your daily cruising plans or routing. These are naturally variable, but in normal use guests typically enjoy reliable overnight cooling and smooth day-to-day operation.

Will someone help us understand the system?

Yes. We are always happy to advise before and during your charter, and if you have a skipper or host on board they will monitor the system and guide you to make sure everything runs as smoothly as possible.

This post was written by Tom Fletcher