DISPELLING THE MYTH: Is Air-Cooling in Generators Really Noisy?

In the marine power world there are many misconceptions that circulate, one frequent belief is that air-cooled engines in generators are noisier than watercooled alternatives - leading many to overlook their benefits. However, Paguro’s air-cooled YANMAR powered generators defy this myth with advanced sound-reducing technology, delivering quiet, efficient operation that rivals, and often surpasses, water-cooled alternatives.

It’s time to clear the air on this topic and look at the facts! Here we break down the rumours surrounding air-cooled engines in generators and explain why Paguro’s designs offer exceptional reliability, simplicity and performance for marine applications.

Why Air Cooling? 

The choice to go with an air-cooled engine, comes with several clear advantages, as Paguro has shown with their YANMAR-powered generators. Unlike water-cooled, air-cooled engines avoid the complexities of water pumps, cooling channels and additional components that require constant maintenance in harsh marine environments. This simplicity isn’t just a design choice; it’s a solution to common problems that water-cooled engines face, especially in saltwater conditions where corrosion and blockages are more frequent.

Air-cooled YANMAR engines are streamlined and straightforward, significantly reducing the likelihood of breakdowns and maintenance issues. This simpler design makes the Paguro generators lighter, more compact and exceptionally easy to service. Many marine engineers appreciate the straightforward nature of air-cooled engines, as it means fewer complications and faster, simpler repairs.

Just how quiet? 

One of the main reasons people assume air-cooled engines are noisy is due to outdated perceptions. Paguro generators with YANMAR engines are renowned for their quiet operation, rated at just 53 dB(A) at 7 metres - quieter than many leading water-cooled generators. 

For comparison, a typical conversation averages around 60 dB, making the 53 dB(A) of a Paguro generator unobtrusive and comfortable onboard. This impressive quietness is the result of thoughtful design and high-quality materials. Paguro generators feature a stainless-steel heat exchanger that maintains optimal engine temperatures even in warmer waters, ensuring both efficient cooling and low noise. The design minimises vibrations and isolates sound, creating a peaceful environment whether relaxing, sleeping or entertaining. With such quiet efficiency, Paguro generators allow boaters to fully enjoy their time on the water, free from the disruptive hum of louder units.

Two Trusted Names

When it comes to reliability, YANMAR engines are a name the marine industry trusts. With a well-deserved reputation for building durable, efficient engines, they are found in everything from commercial ships to recreational boats worldwide. This means that any marine engineer, regardless of location, will be familiar with YANMAR’s systems, making it easier to find qualified maintenance and repair services wherever you go.

In addition, YANMAR engines have become a gold standard for innovation. The compact, air-cooled design makes them an ideal choice for Paguro generators, allowing for high performance without the bulk and complexity that other engines might require. In fact, this design has inspired numerous copycat products, but none have actually matched the efficiency and reliability that YANMAR has achieved with simplicity and smart engineering.

Equally, Paguro’s commitment to quality extends beyond engine selection. Each generator is designed for seamless integration into the marine environment, offering reliable power, easy maintenance, and a compact footprint that maximises onboard space. The air-cooled design reduces issues with saltwater intrusion, rust, and corrosion, ensuring longevity and reliability. With fewer components to maintain, boat owners can trust their Paguro generator to withstand the demands of marine life.

Therefore, the idea that air-cooled generator engines are noisy simply doesn’t hold up under scrutiny. Paguro’s air-cooled YANMAR powered generators offer quiet, efficient and low-maintenance power in a compact, reliable package - proven to be ideal for any marine adventure. With an exceptional noise rating and ease of installation, Paguro isn’t just competitive; it’s setting the standard for dependable power solutions on the water.

Powering Possibilities: Richard Sharp, Remoran and Walrus

With countless miles under his keel and a thirst for adventure, Hallberg-Rassy owner Richard Sharp is no stranger to the demands of long-distance sailing. This January he’ll be setting out on an extraordinary voyage as part of the World ARC rally from St. Lucia. His vessel, Walrus, is a Hallberg-Rassy 39 MK II measuring 12.22 metres and the “baby” of the fleet, making the cut by a mere 2cm. She will be more than prepared, not only with extensive provisioning and forward planning, but with a number of powerful pieces of equipment onboard, notably the Remoran hydrogenerator; a reliable partner in sustainable power.

Summer Test Run

Before tackling the Atlantic, Richard put the Remoran hydrogenerator through its paces this past summer, sailing from Ramsgate down through France, Portugal and Spain. His first impressions of the unit? “At anything above 5 knots, the Remoran was excellent,” he recalls. “Once we hit our stride, it felt like we had an endless supply of energy.” This meant he could spend less time worrying about recharging and more time fully engaged with each destination and leg of the journey.

Richard emphasised that the Remoran started to operate efficiently when Walrus reached a minimum speed of 5 knots upwards, requiring true wind speeds of 8+ knots, and this combination created the best performance from the hydrogenerator. The great news is it provided enough power to keep his fridge, autohelm, watermaker and even Starlink running - all without the need for engine charging.

The Technical Backbone

For those unfamiliar, the Remoran is a hydrogenerator built with efficiency, simplicity and ease of use in mind. When towed behind a boat, it transforms water flow into electrical energy, ideal for long voyages where fuel and charging opportunities may be limited. Richard’s integration of the Remoran with his solar panels and wind generator created a smooth blend of renewable energy sources. As he put it, “It was rare we needed to use the engine to charge much at all - the combination of solar, wind, and the hydrogenerator, gave us more power than we needed.”

Richard credits his decision to purchase the Remoran to an insightful presentation by Rob Cotterill from Advance Yacht Systems earlier in the year. Rob recommended conducting a power audit, which inspired Richard to perform a detailed assessment of his onboard energy needs. The results were then instrumental in helping him understand how purchasing a hydrogenerator would enhance his sailing experience and power supply.

Richard notes that the parasailor he uses flies high and feeds air down through the sail, which in turn generates lift that slightly raises the bow of Walrus, improving both stability and speed. Controlled easily from the cockpit, this is a great choice for short-handed crews, and its performance directly aids the efficiency of the Remoran. Making it an even more versatile addition to onboard systems, the hydrogenerator still works efficiently at night.

Crossing with Confidence

Participating in the ARC demands a reliable power solution, especially when each day at sea brings new variables - from unanticipated weather to unique routing challenges. Whilst joining other sailors navigating the Atlantic’s blue expanse, thanks to the Remoran hydrogenerator, Richard can expect steady power for the entire crossing. “It’s comforting to know that even hundreds of miles from land, I have a solution that doesn’t depend on finite fuel or daily sunshine,” he says. The Remoran’s easy deployment and retrieval are also perfect for this trip; if Richard needs to change course or adjust, he can simply stow it and redeploy it as needed.

Unplugged Freedom

One of Richard’s favourite parts of his new power setup is the sense of independence it affords. “There’s something wonderful about unplugging from the engine,” he laughs, recounting how the Remoran allows him to skip the traditional routines of monitoring fuel and energy levels. He has even replaced all his lightbulbs with LEDs, which makes a big difference in power expenditure.

Richard is mindful of his fuel consumption, carrying 450 litres onboard, he understands the importance of disciplined management. The decision to forgo a diesel generator was a conscious one; wanting to avoid the modifications that such a system would require on his Hallberg-Rassy and, more importantly, the potential impact on marine life. Instead, he has embraced the green efficiencies offered by Remoran and other renewable sources. The plan is to use the watermaker and engine minimally, perhaps every three days, whilst being mindful of Starlink's power drain, so this won’t be left on 24/7. Richard cites his Mastervolt monitor as a handy companion, providing real-time insights into the electricity generated, and reassuring him with a clear indication of positive energy flow to the battery. This has meant he can sail Walrus with confidence, knowing he has a proven sustainable power solution at his fingertips.

New Adventures

Remoran Wave 3GS Hydrogenerator

£2,190.00

Richard’s upcoming journey with the World ARC promises a fresh wave of experiences, all made possible by the confidence he has in his boat’s setup. “With the Remoran, I can genuinely feel like a part of my environment - using the water itself to generate power just adds a deeper level to the adventure.” He is particularly looking forward to the incredible wildlife in the Galapagos and taking in new horizons around Australia. 

As the countdown begins for their World ARC departure, we wish Richard and all his crew fair winds and calm seas. At Advance Yacht Systems we are confident that with the Remoran hydrogenerator, Walrus is well-equipped to tackle whatever lies ahead. 

To follow Richard’s journey - https://www.walrusaroundtheworld.com/ 

How To Efficiently Charge Batteries On-Board Your Boat

When away from shore, being able to charge batteries quickly and efficiently becomes more important so as to not waste fuel and to limit the time charging. Boat manufacturers will often only install sufficient batteries and charging for inshore use, where optimising battery charging is not a priority. When considering offshore sailing and passage making, upgrading your charging system is likely to halve the amount of time required to charge your batteries making charging less of a chore.

Cristec YPOWER+ Battery Charger

How do you work out what is your optimised charge demand from the battery bank? Most battery manufactures will tell you this in their specification document but as a general guide for conventional (Lead Acid, AGM, Gel) batteries, divide the total AH capacity by 5 and you will be pretty close. A 200AH bank would therefore need a 40A charger. Lithium batteries are different, they will typically take everything you give them, and so are usually specified with a charger at 1/3 of the capacity (60A for a 180AH bank).

Charging batteries is best done with a battery charger, driven by shore power or by a generator when at sea. This is the most sophisticated method and is often the most powerful. Think of your batteries as a tank of water. Beginning to fill the empty tank will be easy but as the tank gets nearer too full, the pressure in the tank starts to increase making it harder to push the water in. In electrical terms, the increase of resistance generates heat, so the process needs to be controlled more carefully.

Charging is thus a complex process. The different stages of charging a battery are split into 3 stages: Bulk, absorption and float:

Paguro 4 SY 4KVA Generator

• In the Bulk stage, the charger delivers a maximum level of current (Amps) while the battery is accepting charge easily (from 50% to 80% charge for an AGM battery).

• During the Absorption stage, the charger delivers a fixed voltage to top up the battery (80% to 100%), while the amount of current accepted by the battery reduces down to a trickle.

• For the Float stage, the voltage is reduced, so that a small current is accepted to maintain the battery at 100% charge.

Better quality chargers will control the process better adding more stages, extending the batteries life.

A small 4KVA generator will deliver more than enough power to charge most if not all battery banks. For example, a 220A charger, which would supply a large 700AH (12V) lithium battery bank, would only draw 2,640 Watts from the generator, leaving power for water heating, water making, Starlink broadband or boiling a kettle, and supplying 220V AC powered devices.

Engine alternators are the most common source of charging when at sea. They can be inefficient and not very good at regulating heat, so consider upgrading your alternator alongside a good battery splitter to ensure all battery banks get the maximum charge. High power alternators will run cooler with better output power. In the case of lithium batteries, further regulation should be added to the charging circuit to limit output, protecting the alternator from damage from overheating.

Renewable power such as solar, wind and hydro give you supplementary charge to reduce total charging times. Although they provide relatively small amounts of power compared to a generator or an engine alternator, a continuous stream of power can have a very beneficial effect and can often be paired with high quality multistage chargers. Often, the need to recharge the battery banks using engines or generators can be reduced to once a day or less, when making water and/ or heating water for showers.

A good battery and charging system will make life onboard far less stressful giving you more time to enjoy the experience of life at sea.

Also, checkout our power auditing guide to ensure you have an adequate size battery bank on-board as well as sufficient power generation sources.

Feel free to contact us if you have any questions. Don’t forget to visit us at the Southampton Boat Show on stand J336 in Ocean Hall.

Auditing Power On-board Your Boat

Understanding the power consumption that your boat is likely to use daily can help you prepare for a long passage. By having a clear idea of your boat's energy needs, you can ensure that you have an adequate size battery bank on-board as well as sufficient power generation sources.

Listing out all the items (“consumers”) on your boat with their power consumption and the time they are likely to be used for in each 24-hour window will give you your daily demand. Power for a consumer is often published in an items user manual specification table or printed on the back of the device. This will be given in Watts or Amps. List your audit in Watts. Watts can simply be calculated by multiplying the current (amps) by the relevant operating voltage equalling the power. For example, a 12V light operating at 1Amp is 12 Watts.

• Calculate what each DC consumer uses when operating (this is Amps – Watts divided by volts)

• multiply this by the number of hours it operates in a typical 24 hour period (this is Amp hours)

• add up the Amp hours

This tells you how many Amp hours you will take out of your energy store (the batteries) during a fixed period of time.

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Next you should look at your sources for recharging the batteries (“Producers”). Engine alternator, Generators, hydro, solar and wind will all contribute to varying amounts at maintaining positive charge to your batteries. List these as well, with their power capabilities. Be aware that sources have varying efficiencies: alternators and solar often only give about 60% of their stated capabilities and only the continuous rated outputs of generators should be considered. Battery chargers can also give lower outputs in warmer environments. The producers should be divided into continuous (hydro, solar, wind) which produce power all the time, and top- up (generator, engine alternator) which can be turned on at intervals to top up the batteries.

• Calculate what each continuous DC producer (hydro, solar, wind) produces when operating (Watts)

• multiply this by the number of hours it produces in a typical 24-hour period (this is Watt- hours) and calculate the Amp hours (divide by charging voltage, e.g. 13.8V)

• add up the Amp hours

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The difference between the consumer Amp hours and the continuous producer Amp hours is the gap that you’ll need to fill using your top-up producer(s).  Be aware that the continuous producers may only work for some of the time (while the boat is moving, the sun is shining, or the wind is blowing).

With your daily consumption calculated and charging capabilities, you will now be able to work out how long your batteries will last and take to recharge. For example, a 200AmpHour depletion would take your 80Amp battery charger 2.5hours to fully recharge the battery bank. Ideally, you would not want to be charging you battery bank more than twice daily so an increase in your battery bank size may be required in order to achieve this goal.

Boats have multiple battery banks, but your domestic house bank will be the largest and the one in constant drain. Batteries sizes are given in AH (amp hours). This means that a 100AH battery with a 1Amp load would last 100 hours from 100% SOC (State of charge) to 0% (flat), although discharging by that much will destroy a battery. In practice we look to never discharge lead acid or AGM batteries below around 50%. Batteries have a lifetime, which is defined as the number of full cycles they can be used for. This varies between types of battery technology. A full cycle of a battery is theoretically from 100% SOC to flat so discharging to 50% of the capacity will mean that the battery can be used for twice the number of cycles. Different battery technologies have different discharge capacities: a rule of thumb for Lead Acid/ AGM is a minimum 60% SOC, so assume you only have 40% of your battery capacity as daily usable power. A good battery monitor will give you an accurate battery SOC so can be used as your “fuel gauge” for your battery bank.

Feel free to contact us if you have any questions or need help auditing the power on your boat.

Investing In A Battery Monitor

A good battery monitor is one of the most important devices you can invest in. Battery monitors are crucial to understanding the true state of charge of your batteries on a real-time basis.

Components Of A Battery Monitoring System 

Each battery bank or power source requires a shunt, which allows the monitor to measure the current passing through from a battery’s terminal.

Better monitors will be able to measure multiple shunts and so look after multiple batteries at the same time.

Real-Time Monitoring

A top class battery monitor will display: 

• State of Charge (% of capacity) 

• Discharge rate (Amps) 

• Remaining time before charge required (when discharging) / To max charge (when charging) 

• Voltage 

• Alarms (below safe charge level etc) 

• History 

Data

From voltage levels to discharge rates, you can have a clear picture of battery health and usage patterns. By accessing historical data and alarms for critical thresholds, you can proactively address issues and optimise your power systems for peak efficiency. 

Versatility And Compatibility 

Battery monitors come in various configurations to suit different battery types, applications and power sources. 

Cristec Battery Monitor

One of the best options on the market is the Cristec battery monitor. This device is capable of monitoring 3 battery banks in total or 3 power sources (such as a wind turbine, solar panel or engine alternator) or a mixture of both. You can view all banks on the low energy touchscreen and easily access past data from one place. 

The Cristec battery monitor is equipped with touchscreen display and provides comprehensive data on battery performance 

Each battery bank or power source requires a 300A shunt, one shunt is included with the Cristec battery monitor and additional shunts can be purchased separately. 

One of the key advantages of the Cristec battery monitor is the ability to track the state of charge in real-time. By offering a precise indication of how much charge remains in your batteries, you can avoid unexpected disruptions and plan recharging cycles 

The Cristec battery monitor is versatile and works with a range of voltages, including 12V, 24V, 36V, and 48V. This advanced monitoring system is designed to work seamlessly with various battery types, including Lithium batteries. 

Enhanced Functionality

Beyond basic monitoring capabilities, the Cristec battery monitor offers a host of features like automatic generator starting and CAN-BUS connectivity. These features ensure that your power systems remain efficient and reliable.

Conclusion

In conclusion, battery monitors play a critical role in ensuring the efficiency and reliability of your power systems. With their real-time monitoring capabilities, comprehensive data insights, and advanced functionality, allowing you to maintain a consistent power supply and mitigate potential issues proactively.

Hydrogenerator Case Study

Mike Hutchinson - Oyster 53, “Distraction”

Mike Hutchinson has completed the ARC+ and is planning on taking part on the Oyster World Rally in his Oyster 53, “Distraction”. To minimise use of the engine and generator while underway, he installed a Remoran Wave 3GS from Advance Yacht Systems at the yacht’s home port of Falmouth. Mike chose Remoran because it’s a “beautifully made bit of kit” liking the looks of the unit compared to that of its competitors. “It looks so much nicer”, he says.

Distraction has a distinctive “sugar scoop” transom, so Mike had a stainless-steel rail fabricated onto which to attach Remoran’s “long rail”, so that the hydrogenerator could be retracted from the water when not in use. Mike had brackets and wiring installed for two Remoran units however he has been happy with the performance of just one unit.

Distraction’s DC boat systems are 24V, with 750W of solar panels. Running a fridge, freezer, and other systems while under way, his batteries remained fully charged for the recent long voyage south from Falmouth to Madeira and then on to Lanzarote. The Remoran was on the back of the boat the whole time pushing power into the batteries along with his solar panels. Mike estimates he uses around 200Ah a day.

On reflection after his voyage to the start area for the ARC+ in the Canaries, Mike says he’s “thrilled to bits” with the performance of the Remoran Wave. It delivered the power he needed as he travelled, with little to no maintenance required.

Mike complimented Remoran and Advance Yacht Systems on the support received for the purchase and the installation.

“The Remoran Wave 3GS is a beautifully made piece of kit. It simply sits on the back of the boat and delivers power to our batteries mile after mile. I’m thrilled to bits with the unit, and the installation. The support we got from Remoran and Advance Yacht Systems couldn’t be faulted. Installation went without a hitch, and the unit’s been completely reliable. I do, though, recommend fitting the optional protection relay to prevent overcharging. We sailed to the Scillies in a blow with an ebbing tide on our first outing, doing 14 knots surfing down the waves.”

As of 2024 Mike has completed 7,000 miles with his Remoran calling it ‘one of the simplest and most effective upgrades we’ve made’.

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About Remoran

Highly competitively priced at just £2,190+VAT.

Remoran hydrogenerators allow you to generate power while sailing, without producing any emissions or noise.

• Generate up to 300W

• Start producing power from just 3 knots

• Weighs just 7.5KG

• Feature a telescopic design and up to 40 degrees of adjustment allowing for fitting to most transoms without any adapters

• Supplied as a complete package containing all of the items that you’ll need for installation

• Optional Bluetooth app allows you to monitor:

  • Charging status as Watt-hours gained today

  • Current (Amps) and Power (Watts)

  • Generator RPM display

  • Detects disconnected generator cables and charging cable short circuits

Reduce Your Fossil Fuel Use - Solar vs. Wind vs. Hydrogenerators

Using renewable energy on a boat offers several benefits compared to running your engine. Renewable energy reduces your environmental impact, lowers your fuel costs and reduces engine wear and the need for maintenance. By using renewable energy, you'll also reduce the noise produced by your engine, making your cruising experience quieter and more enjoyable.

When it comes to powering a boat, there are several renewable energy sources to consider, including solar, wind, and hydrogenerators. Each option comes with its own set of advantages and disadvantages, which should be carefully weighed based on the specific needs and circumstances of your boat and its occupants.

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Solar Power

Solar panels are often placed on unused deck space, on a pushpit or on the top of a wheelhouse to harness sunlight and generate energy.

Pros

• Low Maintenance: Solar panels generally require minimal maintenance, reducing the need for ongoing upkeep.

• Silent Operation: Solar panels operate silently, which can provide a quieter environment on the boat.

• Easy Installation: Some smaller variants of solar panels are available. Panels are available from flexible to fully rigid making them easy to mount in any location.

Cons

• Dependent on Sunlight: Solar power generation is dependent on sunlight, which may be limited on cloudy or overcast days.

• Space Requirements: Adequate space on the boat may be needed to install sufficient solar panels to meet energy needs.

• Costly Installation: Larger and more complex installations to provide the extra space can be expensive to install.

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Wind Power

Wind turbines are usually placed at the back of the boat to make use of the empty space and clear airflow. This placement helps the wind turbine produce electricity from the wind.

Pros

• Versatile Installation: Wind turbines can be mounted in various locations on the boat to capture optimal wind conditions.

• Not Sunlight Dependent: Wind power can be generated regardless of sunlight, providing an alternative energy source on cloudy days.

• Power: Can produce significant power in favourable conditions.

Cons

• Noise and Vibration: Wind turbines can produce noise and vibration, which may disrupt the tranquillity of the sailing experience.

• Space and Aesthetics: Placement of wind turbines may require additional space and consideration of aesthetics on the boat due to the mounting pole.

• Potential Interference: Wind turbines may interfere with other equipment or rigging on the boat, requiring careful placement.

• Sailing Direction: They will be less effective when sailing down wind because the apparent wind experienced is less.

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Hydrogenerators

Hydrogenerators are usually installed on the transom, with the turbine below the waterline allowing them to produce power while the boat is sailing. Hull mounted pod units are also an option but are more complex to install.

Pros

• Continuous Power Generation: Hydrogenerators can produce power continuously as your boat moves through the water, regardless of weather conditions or wind direction.

• Low Maintenance: Hydrogenerators are low maintenance and require minimal attention once installed.

• Silent Operation: Hydrogenerators operate silently, producing power as you sail.

• Not Sunlight or Directional Wind Dependent: Hydrogenerators do not rely on sunlight or wind to generator power.

• Generate Power At Low Speeds: Hydrogenerators can start producing power at low speeds, the Remoran hydrogenerators can start producing power at just 3 knots.

Cons

• Requires Sailing to Produce Power: Hydrogenerators will only produce power as you sail meaning they’re perfect for long crossings but won’t produce power stationary (e.g. at anchor).

• Storage: Retracting the hydrogenerator is required during storage and boat manoeuvring in marinas.

• Installation: Requires a stiff mounting surface.

Remoran hydrogenerators feature a telescopic design and up to 40 degrees of adjustment allowing for fitting to most transoms without any adapters. They’re supplied as a complete package containing all of the items that you’ll need for installation and weigh just 7.5KG.

Highly competitively priced at just £2,190+VAT.

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Summary

In summary, solar, wind, and hydrogenerators each have pros and cons for powering a sailing boat. The reliability of hydrogenerators makes them a perfect option for those who will be going on long crossings. In contrast, solar and wind alternatives can be great option to keep you batteries topped up in marinas or at anchor. Using a combination of these systems provides a balanced approach to sustainable energy generation on board.