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Electric Saildrive and Pod Boat Motors

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Welcome to what we believe is the most complete guide to electric saildrive and pod boat motors. It provides top line details for more than 150 individual motors sorted by power range, style and usage. It has been assembled to provide a single place where someone interested in electric marine propulsion can find comparative information for motors made all over the world.

You may also be interested in our other guides »» Guide to Electric Outboards Under 5kW »»  Guide to Electric Outboards Over 5kW »» Guide to Electric Inboards »» Guide to Electric Trolling Motors »» Guide to Electric Boat Batteries

»» Plugboats also has the world’s largest and most complete Directories of over 600 elect ric boats, motors, batteries, accessories, solar panels and rental/charter companies

Information on using this Plugboats Guide

The top of this web page is the Illustrated Guide with photos of the motors and specifications to the right.

Sortable/Searchable Table

At the bottom of the page is a table that can be searched if you know you are looking for a certain type of motor (i.e. pod or saildrive), a certain power range, or for a specific weight/length of boat. If you are going to use the table, the page is best viewed on a computer rather than mobile or tablet.

Illustrated Guide

The motors are organized in alphabetical order by manufacturer, then by style of motor, i.e. fixed pod, steerable pod, saildrive and then by power of motor within those listing. For many styles there are multiple powers of motor available and where that is the case we have made it as easy as possible to line up the motor with its specifications. i.e. if there are three power of motor with different weights, it will be noted as kW: 2kw, 2kw, 3kw • Weight: 10kg, 12kg, 15kg. For some manufacturers the variations are more complicated and we have done our best to make it simple and understandable.

There is a lot of variety in the way manufacturers detail the technical attributes of their products. We have tried to take the most common measurements and assemble an ‘apples to apples’ comparison. See the notes below in ‘Measurements’

The photographs and drawings are from the manufacturers’ websites and are not shown in any consistent scale.

kW • Voltage • Current • HP: Not all manufacturers list all of these specifications. We have included the specifications available and where not available have used the notation N/A.

kW is the kW rating provided by the manufacturer. Most websites do not indicate whether it is input or output kW. When it is indicated, we took the output.

Voltage is most often referred on the sites as ‘Voltage’. Some indicate nominal or peak, we have used nominal and indicated if peak is also referenced.

Current Is noted when the manufacturer supplies the information. Generally it is measured in amperes: A. In some cases the manufacturer uses Amp Hours: Ah and we have noted it where that is used.

HP : is ‘HorsePower equivalent’ so that you can get an idea of the power of the motor in comparison to a HP rating you might be more familiar with. Where available, these measurements come from the manufacturer’s website, and different manufacturers measure the HP in different ways. Some even use metric horsepower, which is slightly different from imperial horsepower. Again, we have tried to make it as apples to apples as possible. (For general guidance, 1kW is round one and a third HP 1kW=1.3HP, or the reverse is that 1HP is around three quarters of a kW: 1 HP = .75kW).

Static Thrust. Torque, Efficiency: This is probably the specification that has the most variability. We have simply given whatever information the manufacturer has published on their website, when available.

Range and Running Time : We have not included estimates of range or running time because it depends on too many factors: battery size (sometimes type also), water conditions, speed, etc. The exceptions are for the ePropulsion and Torqeedo models which have batteries from the manufacturers specifically matched to the motors and therefore provide estimates on their websites.

General : If a manufacturer publishes a specification, we have tried to include it here, even tough other manufacturers may not include the same type of measurement.

Information on this page updated February 4, 2024

You may also want to check our Directory of Electric Boat Motor manufacturers, dealers and distributors around the world, or the Plugboats Marketplace of electric boat motors for sale.

Manufacturers in this Buying Guide: Aquamot • Bellmarine • Combi • Electric Yacht • ELECTRINE • EP Technologies • ePropulsion • E-TECH • Fischer Panda • Gardenergy • Kräutler • Navigaflex • Oceanvolt • Piktronik • Rim Drive Technology • Seadrive • TEMA • Torqeedo

Aquamot was founded in 2003 by engineer Siegmund Hammerstrom and has grown to be a leading manufacturer of electric motors and accessories, including outboards inboards, chargers and batteries. They have two lines of fixed pod motors: Trend and Professional, as well as a line of steerable pods that line up with the power ranges of the Professional line.

Aquamot Trend Fixed Pod 1.1FM and 1.6FM

• Recommended Boat Size: <1.8 tons
• kW : 1.1 / 1.6 • Voltage : N/A • Current : N/A • HP : 3.5 / 5 • Static thrust : 89lbs
• Motor Type : Brushless AC asynchronous • Passive water cooled (motor underwater)
• Weight (kg) : 10.2 / 11.3
• Propeller/RPM : 3 blade fixed, folding optional • RPM : N/A
• Other : Includes: Integrated/removable lithium battery (0.64kWh), charger, display, emergency kill switch. Optional: spare battery, customized compensation wedge, folding propeller ($US 835). Warranty: 2 year limited
• Country of Manufacture : Austria
• Price (MSRP) : $US 2,200 / $2,600

Aquamot Trend Fixed Pod 2.2FM and 4.3FM

• Recommended Boat Size: <4 tons kW : 2.2 / 4.3 • Voltage : 24 / 48 • Current : N/A • HP : 6.4 / 11 • Static thrust : 124 lbs / 197 lbs
• Motor Type : Brushless AC asynchronous• Passive water cooled (motor underwater) Weight (kg) : 12.2 / 13.9
• Other : Includes: Controller, display, basic cables, emergency kill switch. Optional: customized compensation wedge, folding propeller ($US 835). Two year limited warranty.
• Price (MSRP) : $US 3,300 / $3,750

Aquamot Trend Fixed Pod 11.0FM to 25.0FM

• Recommended Boat Size: N/A
• kW : 11 – 25 • Voltage : 48 – 96 • Current : N/A • HP : 28 – 45 • Static thrust : n/a
• Motor Type : Brushless AC asynchronous• Passive water cooled (motor underwater)
• Weight (kg) : 44.3 – 48.9
• Propeller/RPM : 3 blade fixed • RPM : N/A
• Other : Includes: Controller, display, basic cables, emergency kill switch. Optional: customized compensation wedge. Warranty: 2 year limited
• Price (MSRP) : $US 7,150 / $9,915

Aquamot Professional Fixed Pod F10e to F250e

• kW : 1 – 25 • Voltage : 24 – 96 • Current : N/A • HP : 45 – 339 • Static thrust : n/a
• Motor Type : Sensor-less AC asynchronous • Passive water cooled (motor underwater) • Efficiency : 92%
• Weight (kg) : 12 – 50
• Propeller/RPM : 2 blade fixed, folding/feathering optional • RPM : N/A
• Other : Integrated anode, permanently usable for salt or fresh water, maintenance free. Operating efficiency 92%, Included: Custom-made compensation wedge, Controller, throttle, battery monitor, cables, Optional: display, folding/feathering propeller. Warranty: 2 year limited
• Price : N/A

Aquamot Trend Steerable Pod UF10e to UF250e

• Other : Optimized cavitation plate. Permanently usable for salt or fresh water, maintenance free. Operating efficiency 92%, Included: Custom-made compensation wedge, Controller, throttle, battery monitor, cables, Optional: display. Warranty: 2 year limited

»» Bellmarine website

Bellmarine is a very well established electric boat motor company with a history going back to 1999. Along the way they merged with a battery accessory manufacturer and have now been purchased by Transfluid, a large scale industrial motor manufacturer. Bellmarine offers a wide range of electric boat motor configurations, with their saildrive system consisting of their own motor combined with Yanmar drive mechanics. They range from 2kW to 20kW in power with either air or liquid cooling. They also offer a regeneration option. You may want to download the full Bellmarine catalogue

Bellmarine SailMaster Air Cooled Models 2A, 5A, 7A, 10A, 15A, 20A Download .pdf brochure

• kW : Bellmarine uses Nominal and Intermittent kW measurements. These are the intermittent figures: 2, 5, 7, 8, 10, 15, 20 • Voltage : 48V except for the 8A, 15A and 20A models which are 96V • Current : N/A • HP : 2.5, 6.5, 9, 10.5, 13, 20, 25
• Motor Type : Permanent Magnet AC • Air cooled
• Weight (kg) : N/A
• Propeller/RPM : propeller not supplied • RPM : Motor: 1500, Propeller 750 except for 20kW which is Motor 3000, Propeller 1500
• Other : Includes Yanmar SD25 Sail drive leg with 2:1 reduction, motor, controller, , stainless steel motor support brackets.
• Country of Manufacture : Netherlands

Bellmarine SailMaster Liquid Cooled Models 3W, 7W, 10W, 15W, 20W Download .pdf brochure

• kW : Bellmarine uses Nominal and Intermittent kW measurements. These are the intermittent figures: 3, 7, 10, 15, 20 • Voltage : 48V: for all models except 8A, 15A and 20A   –   96V:  Models 8A, 15A, 20A • Current : N/A • HP : 4, 9, 13, 20, 25
• Motor Type : Permanent Magnet AC • Liquid cooled
• RPM : 1500: Models 2A, 5A, 7A, 8A, 10A, 15A   –  3000: Model 20A 

»» Combi website

Combi Outboards was founded in 1979 in Giethoorn (‘the Dutch Venice’) to supply rental boats with clean electric power. It is now a leading international supplier of electric propulsion solutions for the maritime market. Combi manufactures inboards, pods, hybrids and outboards. There are six pods ranging in power from 1kW to 3.5 kW: 1, 1.5, 2, 2.5, 3 and 3.5kW. They are available both as fixed pod or steerable pods.

Combi Nautic Fixed Pod/Saildrive Download .pdf brochure

• kW : 1.0 – 3.5 • Voltage : 24 (1.0kW + 1.5kW), 48 (2.0kW – 3.5kW) • Current : 42A – 73A • HP : 4 – 9
• Motor Type : Asynchronous AC • passive water cooled Weight (kg) : N/A
• Propeller/RPM : 3 blade fixed – 220mm or 230mm • RPM : 1050 (3.5kW 1300) Other : “Easy Connect” system delivered Plug & Play for owner installation. 

Combi Nautic Steerable Pod Download .pdf brochure

The Steerable Pod Nautic models have the same specifications as the Saildrive models above.

• Motor Type : Asynchronous AC • passive water cooled
• Propeller/RPM : 3 blade fixed – 220mm or 230mm • RPM : 1050 (3.5kW 1300)
• Other : “Easy Connect” system delivered Plug & Play for owner installation. 

Electric Yacht

Electric Yacht is one of the premier US suppliers of saildrives. They have developed a Plug-n-Play system that has been engineered for quick, simplified installation as well as long term durability. Their systems offer regenerative power while under the sail. 10 years of proven production with over 450 installs. 3 Year Warranty

Electric Yacht QuietTorque™ 10.0 Sail Drive

• Recommended Boat Size: <6 tons – 34’ (10m)
• kW : 10 • Voltage : 48 • Current : 200A • HP : 10.5
• Motor Type : Brushless PMAC
• Weight (kg) : 45
• Propeller/RPM : 2 or 3 blade, fixed or folding, 12”  – 16” • RPM : N/A
• Other :  Installs through 9” hole, Anodized aluminum frame and waterproof throttle,Digital Display of: State of Charge (SOC, Voltage, Current, Power, Motor RPM, time to discharge based on current power consumption, updated in real time, Programmable regeneration. 3 Year Warranty. 
• Country of Manufacture : USA
• Price (MSRP): $US 11,995

Electric Yacht QuietTorque™ 20.0 Sail Drive

The Electric Yacht Quiet Torque 20 is essentially the 10.0 with twin motors

• Recommended Boat Size: <12 tons – 45’ (14m), catamarans 40’-46’ (12-15m)
• kW : 20 • Voltage : 48 • Current : 400A • HP : 21
• Motor Type : Brushless PMAC X 2
• Weight (kg) : 77 Propeller/RPM : 2 or 3 blade, fixed or folding, 12”  – 18” • RPM : N/A
• Other :  Installs through 9” hole, Anodized aluminum frame and waterproof throttle,Digital Display of: State of Charge (SOC, Voltage, Current, Power, Motor RPM, time to discharge based on current power consumption, updated in real time, Programmable regeneration. 3 Year
• Warranty. 
• Price (MSRP): $US 14,695

Also: Electric Yacht QuietTorque™ 30.0 Sail Drive (boats <14 tons) Electric Yacht QuietTorque™ LC 45 Sail Drive (boats <17 tons) Electric Yacht QuietTorque™ LC 60.0 Sail Drive (boats <22 tons)

• Recommended Boat Size: 14 tons – 22 tons, 45’- 60′ (15-18m)
• kW : 30 – 60 • Voltage : 48 – 96 • Current : 300Ah – 600Ah • HP : 48 – 65
• Motor Type : Brushless PMAC X 2 • liquid cooled
• Weight (kg) : 100 – 106
• Propeller/RPM : N/A
• Other :  Installs through 9” hole, Anodized aluminum frame and waterproof throttle, Digital Display of: State of Charge (SOC, Voltage, Current, Power, Motor RPM, time to discharge based on current power consumption, updated in real time, Programmable regeneration. 3 Year Warranty. 
• Price (MSRP): $US 19,995 – 23,495

»» ELECTRINE website

ELECTRINE is a Korean manufacturer which has focused on maritime electrification since 2010, when the idea of electric mobility was still relatively uncommon. The company was known as LGM until 2020 and has had a consistent R&D effort for many years. They manufacture electric outboards, inboards and saildrives as well as accessories and Lithium-ion batteries using a Carbon Nano Tube heat exchanger technology. Ther are 6 motors in their eSaildrive line, ranging from 8 kW to 110 kW.

ELECTRINE eSaildrive line: S-8, S-16, S-25 (shown), S-40, S-80, S-110

• Recommended Boat Size: Daysailer / Racing / Monohull /Multihull
• kW : (Max) 8, 16, 25, 40, 90, 110 • Voltage (Vdc): 48, 48, 96, 96, 345.6, 345.6
• Motor Type : N/A
• Weight (kg) : 40.5, 46.5, 50.5, 172, 198, 218
• Other : Hydrogeneration on 8kW and 16kW models. ELECTRINE also makes batteries customized for the motors
• Country of Manufacture : Korea
• Price (MSRP): N/A

EP Technologies

»» ep technologies website.

EPTechnologies is a complete marine propulsion provider for electric and hybrid vessels. The company specializes in custom electric and hybrid systems, but also has ‘off the shelf’ motors, including a range of saildrives. Their Electric Turnable Saildrive offers 360-degree rotation, the key advantage being that no additional thruster is required behind the boat. Other saildrives (SD-25, SD-60, SD-15) have a fixed lower unit. All saildrives are include a complete system utilizing batteries designed and built by EP Technologies.

EP Technologies Turnable Saildrive

• kW : 25 – 60
• Voltage (VDC): 100 – 800
• RPM : 500 – 2000
• Other : 360° Rotatable, Electric servo motor, Joystick Control
• Country of Manufacture : Denmark
• Price : Contact EP Technologies

EP Technologies Saildrives: SD-25, SD-50, SD-15

• kW : SD-25: SD-60: 25, 39, 60, SD-15: 65, 95
• Voltage (VDC): SD-25: 48, SD-60: 100 – 800, SD-15: 400 – 800
• RPM : SD-25: 1000 – 2000, SD-60: 500 – 2000, SD-15: 500 – 2000

ePropulsion

»» epropulsion website.

ePropulsion was  founded in 2012 by three engineers from the Hong Kong University of Science and Technology (HKUST).  The company continues to have a strong engineering culture where each engineer is individually responsible for creating as much value for users as possible. ePropulsion offer two pod models based on their outboards: the 1kW Spirit and 3kW Navy.

Click here to view motors from ePropulsion dealers in the Plugboats Marketplace

ePropulsion Pod Drive Evo 1.0 , 3.0, 6.0

• kW : 1, 3, 6 • Voltage : 40.7, 48 • Current : 25A, 62.5A • HP : 3, 6, 9.9 Static Thrust : 71, 132.6
• Weight (kg) : (Including integrated battery) 14.1, 15.6
• Propeller/RPM : Spirit: 2 blade, 28 × 14.7 cm (11′ × 5.8″), Navy: 2 blade, 26 × 17.1 cm (10.2″ × 6.7″), RPM: Spirit 1200, Navy 2300
• Other : Hydrogeneration, Includes battery and wireless remote controller (cable option also), Spirit has 1.1 kWh lithium battery, Navy has 3.0 kWh
• Country of Manufacture : Hong Kong/China

»» E-TECH website

E-TECH is a subsidiary of boatbuilder Starboats that was started in 2008 because they were dissatisfied with other electric motor offerings in the market at the time. The company has developed fixed pods, steerable pods and outboard motors that all utilize an in-water BLDC (BrushLess DC permanent magnet) pod motor in a watertight aluminum casing. There are 5 pod models available in both fixed pod and steerable pod configuration. All of these are equipped with the ruddershaft, tube and steering lever. There are also 4 models of high torque pods available only in fixed pod format.

Click here to view motors from E-TECH dealers in the Plugboats Marketplace

E-TECH 4 POD, 7 POD, 10 POD, 15 POD, 20 POD Link to Fixed Pod Motors • Link to Steerable Pod Motors Download .pdf brochure

• kW : 4.3, 7.5, 10.9, 16.6, 19.5 • Voltage : 48, 48, 48, 72, 96 • HP : ≈ 6, 10, 15, 22, 27 • RPM : 1350, 1350, 1470, 2240, 2200
• Motor Type : Brushless PMDC • water cooled
• Other :  Includes controller, display with battery monitor, joystick (side- or top mounting), 2m steering cable, 5m connecting cables between controller and steering position (standard 5 meter).
• Country of Manufacture : Poland

The four High Torque E-TECH PODH engines are designed for those applications where a very high torque is needed.

E-Tech High Torque PODH: 13 POD, 18 POD, 23 POD, 35 POD Download .pdf brochure

• kW : 11.9, 16.7, 21.5, 33.7 • Voltage : 48, 72, 96, 144 • HP : ≈ 16, 23, 29, 45 • RPM : 760, 1140, 1520, 2500

Fischer Panda

»» Fischer Panda

Fischer Panda is one of the world’s best known manufacturers of marine generators but are also manufacturers of high quality electric boat motors, sometimes marketed under the ‘Whisperprop’ name. They have an “EasyBox” system that is intended to take the guesswork and complication out of purchasing electric boat motors.

Fischer Panda 48V Underwater Drive System (Easybox) Download .pdf brochure

• kW : 3.8 – 20.0 • Voltage : 48 • Current : N/A • HP : 5 – 25
• Motor Type : Brushless Permanent Magnet (PMAC)
• Weight (kg) : 18.7 – 120
• Propeller/RPM/Torque : Propeller not included • RPM : 600 – 2500 Torque (nM) : 28 – 320
• Other :  Includes: Fischer Panda EasyBox control unit, control panel, throttle Options: Propeller, propeller protector, battery bank, charger, shore power connection.  
• Country of Manufacture : Germany

Fischer Panda EasyBox HV High Voltage System Fischer Panda Download Centre

• Recommended Boat Size: <40 tons
• kW : 50, 80, 100 • Voltage : 360 – 420 • Current : N/A • HP : 65 – 125
• Weight (kg) : 42
• Propeller/RPM/Torque : 5 blade fixed • RPM : 1200 / 1900 Torque (nM) : 398 – 400
• Other :  These motors are generally designed for use by small public transportation ferries, commercial working vessels and privately owned leisure yachts. Systems should be customized.

»» Gardenergyy website

Gardenergy is an Italian company established to offer ‘a simple and reliable product featuring cutting-edge technology’. They use the same motors in a variety of ways, cleverly configuring them for outboard, inboard shaft drives, and either fixed pods or steerable pods.

Gardenergy Pod

To see options and download .pdf brochures, go the Gardenergy site and click on ‘Links’. A pop up will appear with options. There is also an option for price list and a Configurator which can help with system assembly and pricing.

There are five Gardenergy pods with power input of: 2kW, 4.3 kw, 6kW, 8kw, 10kW. They are available as fixed or steerable pods.

• kW : 2, 4.3, 6, 8, 10 • Voltage : 48 except for 2kW which is 24V • Current : N/A • HP : 2.5, 5.5, 7.5, 10, 13
• Motor Type : PMAC
• Propeller/RPM/Torque : 3 blade fixed, folding available • RPM : 2kW: N/A, 4.3kW: 1450, 6kw: 1600, 8kW: 1750, 10kW: 1950
• Country of Manufacture : Italy
• Price (MSRP): Download MSRP Price List $US 3,975 – 6,625

»» Kräutler website

Kräutler is a long-established Austrian manufacturer of industrial electric motors. They began construction of electric boat motors in the 80’s mainly because they could not find a product that would live up to the standards of founder Oswald Kräutler. They make motors for industrial and ship use as well as recreational boats and probably offer the widest range of sailpods and saildrives on this page with everything from small .5kW steerable pods to electrically rotatable saildrives with power up to 30kW.

An explanation about the Kräutler section of this guide: The Kräutler fixed pods are available with AC motors (ACV) or DC motors (GPV). The AC are for smaller boats. They also come in two different configurations: fixed propeller and folding propeller. In the interests of making this page shorter, we have divided them in to the motor types for the written descriptions but have shown you the fixed and folding options in the images. In the table each of the motors has a separate listing. NOTE: The GPV motors are only suitable for short use in salt water.

Krautler Submersible Flange Motor Pods with D C motors Download .pdf brochure

• MOTOR TYPE: GPV
• Recommended Boat Size: <1.9 tons
• kW : 0.5, 0.8, 1.6, 2.2 • Voltage : 24 except for 2.2kW which is 36V • Current : 21, 34, 67, 61 • HP : 0.5, 1.0, 1.8, 2.5
• Motor Type : GPV: DC motor with permanent magnets, continuous control 
• Weight (kg) : 14, 15, 20, 20
• Propeller/RPM/Torque : 3 blade fixed or folding (see intro note above) • RPM : N/A • Torque : N/A
• Other :  ATTENTION: GP motors are only suitable for short use in salt water. Includes: Motor, bracket, electric regulation system, throttle, status display monitor, battery monitor, cables, battery master switcher & fuse, propeller, anode. Operating efficiency 85%
• Price (MSRP):

Krautler Submersible Flange Motor Pods with AC Motors Download .pdf brochure

• MOTOR TYPE: ACV
• Recommended Boat Size: <10 tons
• kW : 1.8, 2.0, 4, 8, 10 • Voltage : 24 (1.8, 2.0kW) 48 (4, 8, 10kw) • Current : 100, 107, 104, 202, 250 • HP : 2.3, 2.5, 5, 10, 13
• Motor Type : ACV: AC brushless three phase asynchronous motor  
• Weight (kg) : 21, 29, 29, 40, 50
• Other :  Includes: Motor, bracket, electric regulation system, throttle, status display monitor, battery monitor, cables, battery master switcher & fuse, propeller, anode. Operating efficiency 75% – 83%

Krautler Submersible Pod with Tiller Handle Download .pdf brochure

• MOTOR TYPE: ACV or GP
• Recommended Boat Size: Sailboat: <10 tons, Powerboat: <6 tons
• kW : 0.5 – 10 • Voltage : 24, 48 • Current : 21 – 250 • HP : 0.5 – 13
• Motor Type : ACV: AC brushless three phase asynchronous motor • GP:  permanent magnet with continuous control 
• Weight (kg) : 15 – 54
• Propeller/RPM/Torque : 3 blade fixed • RPM : N/A • Torque : N/A
• Other :  Includes: Motor, bracket, electric regulation system, throttle, status display monitor, battery monitor, cables, battery master switcher & fuse, propeller, anode. Tubes/diaphragms available for installation. Standard shaft length: 450mm. Operating efficiency 75% – 85%

Krautler Saildrive Compact Download .pdf brochure

• Recommended Boat Size: <4 tons
• kW : 2.0, 3.0, 4.0 • Voltage : 24, 36, 48 • Current : 104, 100, 99 – 250 • HP : 0.5 – 13
• Motor Type : AC brushless three phase asynchronous motor with continuous control 
• Weight (kg) : 42, 42, 42,
• Propeller/RPM/Torque : Propeller not included • RPM : N/A • Torque : N/A
• Other :  ATTENTION: SDK drives are only suitable for short use in salt water. Includes: Motor, saildrive gear, base plate for lamination (depending on motor size), electric regulation system, throttle, status display monitor, battery monitor, cables, battery master switcher & fuse. Operating efficiency 80%, 83%, 84%

Krautler Saildrive Fixed Download .pdf brochure

• Recommended Boat Size: Sailboat: <30 tons, Powerboat <12 tons
• kW : 2.5 – 30.0 • Voltage : 24 – 144 • Current : 104 – 370 • HP : 3.5 – 40
• Motor Type : AC brushless three phase asynchronous motor with continuous control. MOTORS 15.0 – 30.0kW are water cooled.
• Weight (kg) : 45 – 91
• Other :  ATTENTION: Water cooled drives are only useable in seawater with 2-circle water cooling. ATTENTION: SDK drives are only suitable for short use in salt water. Includes: Motor, saildrive gear, base plate for lamination (depending on motor size), electric regulation system, throttle, status display monitor, battery monitor, cables, battery master switcher & fuse. Operating efficiency 85% – 88%

Krautler Saildrive Mechanical Rotatable: 2 x 45° Download .pdf brochure

All of the Krautler motors with specs shown in the fixed saildrives above can be installed with a mechanical rotatable option shown here or electric rotatable option shown below. The Sail-Drive is supplied with a fiberglass foundation base, which can be laminated to the hull (depending on motor size). For existing Volvo and Yanmar foundations the Sail-Drive is equipped with an adapter plate and can be screwed directly on the existing foundation.

Krautler Saildrive Electric Rotable: 2 x 90° or 360° Download .pdf brochure

All of the Krautler motors with specs shown in the fixed saildrives above can be installed with an electric rotatable option shown here. The Sail-Drive is supplied with a fiberglass foundation base, which can be laminated to the hull (depending on motor size). For existing Volvo and Yanmar foundations the Sail-Drive is equipped with an adapter plate and can be screwed directly on the existing foundation. The electrical rotating mechanism includes an actuating drive with gearbox, electric regulation system for the drive, a steering lever and display.monitor indicating propeller position

»» Navigaflex website

The innovative Navigaflex motor has a Patent Pending design in which the motor itself retracts and pivots and can attached to the boat as an outboard or inboard motor. The motor is made with a minimum of parts, a light construction and is adaptable to all boat hulls. The standard motor can also be ordered with a “booster” to double the power for up to 2 minutes.

Navigaflex Motor

• Recommended Boat Size:  2 tons / 8m – 16 tons / 18m kW : 6kW, 8kW, 10kw, 15KW • Voltage : 48 (nominal) • HP : 8, 11, 13.5, 20
• Motor Type : Brushless Permanent Magnet (PMAC) • Water cooled (10kW and 15KW)
• Weight (kg) : 54 (4KW) – 68 (15KW)
• Propeller/RPM : 2 blade fixed •  RPM : N/A
• Other : Retractable motor, Option to regenerate the current under sails, Digital motor controller with touch screen and mobile phone connected remotely.
• Country of Manufacture : Switzerland
• Price : $US 8,000 – 16,000

»» Oceanvolt website

Oceanvolt is one of the best known names in saildrives and its ServoProp regenerating system is regarded as one of the first and best. It is difficult to provide full information about their systems because their website encourages customers to provide information for customized solutions. These are some basics

Click »» here to see Oceanvolt motors for sale from vendors in the Plugboats Market

Oceanvolt SD Saildrive See more detailed information

• Recommended Boat Size:  < 80 ft / 25m
• kW : 6, 8, 10, 15 • Voltage : 48 • HP : 8, 11, 13.5, 20
• Motor Type : Synchronous permanent magnet • Closed circulation liquid cooling provides cooling and lubrication
• Weight (kg) : 42.5, 42., 46.5, 46.5
• Propeller/RPM : Propeller not included •  RPM : 2200 • Gear Reduction Ratio : 1.93: 1
• Other : Includes: Battery communication kit, hydrogeneration feature • Sold separately: Batteries, Charger, Propeller • Sail Drive with 1.93:1 reduction. Closed circulation liquid cooling provides cooling and lubrication. 10kW and 15kW systems include 15.2kWh Li-ion battery bank, charger
• Country of Manufacture : Finland
• Price : $US 13,500 – 45,000

Oceanvolt Servoprop Saildrive

The Oceanvolt ServoProp is a patented variable pitch sail drive that ‘combines a high efficiency sail drive with the most powerful hydro generator on the market’. Unique feature is the possibility to turn the propeller blades more than 180 degrees. The software controlled variable pitch sail drive adjusts the pitch of the propeller blades automatically so that the power generation and power output are optimal. The blades are designed to give the system maximum efficiency in forward, reverse and regeneration. With the blades set to the neutral sailing position, the propeller creates extremely low drag similar to the drag of a feathering propeller. ServoProp is capable of generating more than 1 kW at 7-8 knots & 3 kW at 11-12 knots.

»» Piktronik website

Piktronik is an Austrian-Slovenian company working on the research, development and production of components for electrical vehicles (EV) and boats. Their pods are available in a variety of configurations that vary by the power output. We have noted that below. They also sell motors as complete systems with batteries and chargers.

Piktronik UWM1 – UMW10 On arriving at the linked page, there are links for each motor to download more information

• kW : 1, 2, 5, 6.5, 10 • Voltage : 16, 17, 30, 30, 30 • Current : 50, 92, 120, 150, 200 • HP : 1.4, 2.7, 6.8, 8.8, 13.6
• Motor Type : PMSM (permanent-magnet synchronous)
• Weight (kg) : 18, 23, 25, 51, 95
• Propeller/RPM/Torque : 2 blade fixed – 4 blade fixed • RPM : 1100, 1200, 1850, 1200, 1000 • Torque (nM) : 7, 14, 27, 51, 95
• Other :  Aside from the complete system detailed below the motors alone come in different configurations: 1kW and 2kW: steerable pod or fixed pod, 5kW: steerable pod, fixed pod, transom mount, 6.5kW: steerable pod or transom mount, 10kW: steerable pod or transom mount
• Country of Manufacture : Slovenia

Piktronik SYS Systems 1kW – 10kW On arriving at the linked page, there are links for each motor to download more information

Piktronic sells their motors in complete system kits for each of the motor sizes detailed above. Complete system includes: motor, motor controller, display monitor, cables, siwthces, fuses, battery charger, remote comtrol, steering arm, installation tube, tiller handle, propeller

Rim Drive Technology

Click here to view RIM Drive Technology motors for sale in the Plugboats Marketplace

»» Rim Drive Technology website

Rim Drive technology is a Netherlands company with a line of rim motors in which the propeller blades are affixed to a rim rather than a central hub. There are no wearing parts within the motor and much reduced chance of weeds or other debris snagging or clogging. The motors are available as outboards, pods, azimuths and thrusters. The company offers complete systems or standalone batteries, controllers, monitors and other accessories. The pods in the Guide are sorted as 24V, 48V and 48V+. All pods are available with extended shaft options to reduce hull effects on the rim drive water flow for quieter and smoother operation.

24V Pods POD 3.0, POD 5.0

• kW : 3.0, 5.0 •  Voltage : 24 •  HP : 6.5, 11.0 • Thrust (kg) : – 31, 62
• Battery : Sold separately, recommended LiFePO4 available from Rim Drive
• Running Time : Suggested 4-5 hours with recommended Rim Drive battery pack
• Shaft Length (cm) : N/A extended shaft length available
• Propeller Diameter (mm) : 86, 133
• Weight (motor only) (kg) : 3.5, 5.0
• Other : One year warranty for non-commercial use, Completely waterproof (IP68), Efficiency 90+, Includes 2m cable set
• Price : €3,340, €4,000

48V Pods: 5 motors POD 0.5, POD 3.0, POD 5.0, POD 11.0, POD 15.0

• kW : 0.5, 3.0, 5.0, 9, 11, 16 •  Voltage : 48 •  HP : 1, 6.5, 10, 20, 28 • Thrust (kg) : – 7, 31, 62, 156, 250
• Running Time : Up to 7 hours with suggested Rim Drive battery pack
• Propeller Diameter (mm) : 65, 86, 133, 212, 341
• Weight (motor only) (kg) : 2.5, 3.5, 5.0, 14.0, 70.0
• Price : €3,300, €3,400, €4,000, €6,850, €18,000

96V, 110V, 400V Pods POD 25.0, POD 30.0, POD 50.0

• kW : 25, 30, 50 •  Voltage : 96, 110, 400 •  HP : 42, 52, 74 • Thrust (kg) : – 380, 400, 750
• Running Time : Average 3 hours with suggested Rim Drive battery pack
• Propeller Diameter (mm) : 341, 341, 341
• Weight (motor only) (kg) : 70, 70, 75
• Price : €25,000, €25,000, €48,000

Steerable Pods (8 models) Steerable POD 3.0, 5.0, 8.0, 11.0, 15.0, 25.0, 30.0, 50.0

• kW : 3, 5, 8, 11, 15, 25, 30, 50 •  Voltage : 48, 48, 48, 48, 48, 96, 110, 400-550 •  HP : 42, 52 • Thrust (kg) : 31, 62, 120, 156, 195, 350, 400, 750
• Weight (kg) : 21.5, 23, 32, 32, 37, 110, 110, 110
• Other : Rotatable up to 200 degrees, Waterproof hull passthrough, Stainless steel or glass fibre seal available, Salt water resistant (IP68), Motor controller included, Joystick, steering wheel or CAN controlled
• Price : €7,350, €8,225, €12,075, €12,375, €14,900, €31,995, €31,995, €55,500

»» SeaDrive website

SeaDrive is a Norwegian manufacturer that has an innovative approach to pods, saildrives and all electric boat motors for which they received a nomination for a 2019 DAME Award. The concept is that the basic motors can be configured: fixed pods, steerable pod, a saildrive or lift-up azimuth side pod – also with the ability to have the propellers arranged for push propulsion or pull propulsion.  There are also regenerative versions available. The pod motor systems come in three power ratings: 7.5, 15 and 30.

SeaDrive Modular Pods/Saildrives/Lift-Up Azimuths

• kW : 5-7.5, 10-15, 20-30 • Voltage : 48, 96, 144 • Current : NA • HP : 7.5, 15, 32 • Static Thrust: 90, 160, 300
• Weight (kg) : Motor Weight: Aluminum: 20, Bronze 23. Total Weight differs by configuration
• Propeller/RPM/Torque : Fixed or folding • RPM : N/A • Torque N/A
• Other :  re-generative versions and TABLET/PC control.
• Country of Manufacture : Norway

»» TEMA website

TEMA is a Croatian company that makes highly regarded electric motors that can be purchased alone or in systems for marine, industrial and power generation applications. Their saildrive system uses their SPM132 series of very efficient compact permanent magnet motors. The motors operate on either DC or AC voltages and can be powered from battery systems (48 96Vdc) or generators.

TEMA SYS Systems 1kW – 10kW Download .pdf of Systems configuration Download .pdf of SPM Motors

• kW : For each of their models TEMA has dual figures – kW output at 1800/3600 RPM. The 5 models range in listed power from 12/19kW to 35/57kW • Voltage : There 48 and 96 Voltage availble for all models. • Current : 50, 92, 120, 150, 200 • HP : At 1800/3600 RPM they range from 25/39 to 47/76
• Motor Type : PMAC (Permanent Magnet AC), PMS (Permanent Magnet Synchronous) • Air cooled
• Weight (kg) : 73, 93, 110, 130, 148
• Propeller/RPM/Torque : Propeller not supplied • RPM : 1800/3600 across all motors • Torque (nM) : Maximum: 70, 111, 145, 178, 205
• Other :  Includes all components: e-motor, motor controller, saildrive, marine throttle, display, plug and play wiring. Efficiency: 95%.
• Country of Manufacture : Croatia

»» Torqeedo website

Torqeedo is the world’s leading manufacturer of electric outboards. The company was founded in 2004 by Dr Christoph Ballin and Dr Friedrich Böbel when they decided they could build a better electric motor than the one on the boat Dr. Ballin had just purchased. The company offers trolling motors, inboards, outboards and pod motors and works with BMW’s battery division as well as partnering with many of the world’s premier boat designers and manufacturers. It may be useful to download the full Torqeedo Catalogue

Torqeedo Cruze FP Pod 2.0 – 4.0 Operating instruction .pdfs can be downloaded from link above

• kW : 2, 4 • Voltage : 2kW: 24, 4kW: 48 • Current : N/A • HP : 6, 9.9 • Static Thrust 155 lbs, 189 lbs
• Motor Type : Brushless External Rotor Motors with Rare-earth Magnets • Operating efficiency 56%.
• Weight (kg) : 15.4, 15.8 Propeller/RPM/Torque : 3 blade fixed or folding • RPM : 1300
• Other :  GPS on-board computer & display: Real-time speed, input power. Operates with lithium or AGM/lead-gel batteries, exact battery status and remaining range available when using Torqeedo battery. Emergency magnetic kill switch.
• Price (MSRP): $US 4,549, 4,999

Torqeedo Cruze FP Pod 10.0 Operating instruction .pdfs can be downloaded from link above

• Recommended Boat Size: <10 tons kW : 10 • Voltage : 48 • Current : N/A • HP : 20 • Static Thrust ≤ 405 lbs
• Weight (kg) : 33.5
• Propeller/RPM/Torque : 5 blade fixed or folding • RPM : 1400
• Other :  Includes: Remote throttle, integrated on-board computer with GPS-based range calculation, 70 mm² cable set (3 m) including fuse and main switch, plug connector. 2 year warranty.
• Price (MSRP): $8,999

Torqeedo Cruze FP Saildrive 10.0 Operating instruction .pdfs can be downloaded from link above

• kW : 10 • Voltage : 48 • Current : N/A • HP : 20 • Static Thrust ≤ 405 lbs
• Weight (kg) : 37

Torqeedo Deep Blue 25 Saildrive

• Recommended Boat Size: <50 tons
• kW : 25 continuous, 33 peak • Voltage : 345 • Current : N/A • HP : 40 • Static Thrust ≤ 405 lbs
• Motor Type : Brushless External Rotor Motors with Rare-earth Magnets • Operating efficiency 55%.
• Weight (kg) : 125, 314 total system including 1 battery
• Propeller/RPM : Propeller : not included • RPM : 1200
• Price (MSRP): On Request with requirements input

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The Promises and Pitfalls of an All-Electric Yacht

• By Tim Murphy
• Updated: November 8, 2021

This past October, I saw one of the most interesting exhibits in more than 500 new cruising sailboats I’ve reviewed over two decades. It was the Arcona 435Z, built in Sweden and introduced by Graham Balch of Green Yachts in San Francisco. Balch describes his business as “a new brokerage dedicated to the electric revolution on the water,” and it was the “Z” in the boat’s name, which stands for “zero emissions,” that made this boat so interesting. This was the first electric propulsion system—not hybrid but all-electric —I’d ever seen on a cruising sailboat.

Electric propulsion isn’t new. Since 1879, electric motors have propelled boats; a fleet of some four-dozen electric launches transported visitors around the 1893 Colombian Exposition in Chicago. But cruising sailboats are not launches, and the open sea is not a protected canal. When we’re using cruising boats as they’re meant to be used, they seldom end their day plugged into a shore-power outlet. Cruising boats comprise many devices —stove, refrigerator, freezer, windlass, winches, autopilot, radar, lights—whose power typically comes from a tank of fossil fuel. And today’s cruising sailors are accustomed to using diesel auxiliary power to motor through lulls or punch into headwinds and seas.

Starting about 15 years ago, we saw a wave of diesel-electric and hybrid propulsion systems on production and custom cruising boats ( see “Perpetuated Motion,” CW , March 2005 ). Both of those systems ultimately start with an onboard internal-combustion engine. A diesel-electric propulsion system relies on a running genset to directly power the electric motor that turns the propeller. A hybrid system relies on batteries to power the electric motor, plus an internal-combustion genset to recharge the batteries. One of the promises of a hybrid system is the ability to regenerate electrical power. Regeneration means using boatspeed under sail to turn the propeller, whose spinning shaft sends electrons from the electric motor back through an electronic controller to recharge the batteries. In such a system, the boat’s propeller is both an electrical load (when running under power) and a charging source (when sailing in regeneration mode).

The Arcona 435Z was different from both of these systems: It incorporates no onboard fossil-fuel engine at all. Instead, it has a bank of lithium batteries, several solar panels, and a proprietary propulsion leg that looks like a saildrive. “This boat,” Balch said, “has the very first production unit in the world of Oceanvolt’s newest electric propulsion system, called the ServoProp.”

For our sea trial, Balch was joined by Derek Rupe, CEO of Oceanvolt USA. “If you can sail the boat and you have some solar, you can go anywhere in the world, and you can make all your power underway while you go,” Rupe said. When we spoke in October 2020, he touted three high-profile sailors who were using the Oceanvolt electric propulsion system: Alex Thomson, for his Hugo Boss Open 60 Vendée Globe program; Jimmy Cornell, for his Elcano 500 expedition; and Riley Whitelum and Elayna Carausu, who had been teasing their new boat for months on their popular Sailing La Vagabonde YouTube channel.

The efficiency of Oceanvolt’s ServoProp and the regeneration from it is the promised game-changer in each of these boats. The ServoProp is a leg with a ­feathering propeller that can be set for optimal pitch in three modes: forward, reverse and regeneration.

“You don’t need fuel,” Rupe said. “You don’t need to dock; you can go anywhere you want to go and always have the power for living and propulsion.”

That’s the promise. But are there also pitfalls?

Innovation and Risk

Marine electric propulsion is an emerging technology. Compared with the mature and settled technology of diesel engines and lead-acid batteries, electric-propulsion systems—with their electronic controllers and lithium batteries—are in a stage of development best described as adolescent. Every sailor has his or her own tolerance for technical innovation. For the promise of fewer ­seconds per mile, grand-prix-racing sailors willingly trade a high risk of expensive damage to the sails, rig or the boat’s structure itself; cruising sailors, by contrast, tend to favor yearslong reliability in their equipment as they seek miles per day.

Folks who identify as early adopters take special joy in the first-wave discoveries of a new technology; if they’re clear-eyed about supporting an ongoing experiment, they see themselves as partners with the developers, accepting failures as opportunities for learning. Sailors motivated primarily by changing the trajectory of climate change might be especially willing to modify their behavior to limit their own output of greenhouse gases. Investing in any emerging technology asks you to start with a clear assessment of your own risk tolerance. We’ll return to this theme with one or two real-life examples.

The American Boat and Yacht Council, founded in 1954, sets recommended standards for systems installed on recreational boats. For decades, ABYC has published standards related to installations of diesel and gasoline engines, as well as electrical systems based around lead-acid batteries. By contrast, it was only three years ago that ABYC came out with its first electric-propulsion standard (revised July 2021). And only last year it published its first technical-information report on lithium batteries (a technical-information report is an early step toward a future standard). The takeaway is that if you need help servicing your diesel engine or electrical system built around lead-acid batteries, you can pull into any reasonable-size port and find competent technicians to help you. With electric propulsion and lithium batteries, that pool of skilled talent is significantly scarcer.

To say that a technology is mature simply means that we’ve learned to live with it, warts and all, but that it holds few remaining surprises. Certainly, diesel-propulsion and lead-acid-battery technologies each leave plenty of room for improvement. When a charge of fuel ignites in the combustion ­chamber of a diesel engine, some three-quarters of the energy is lost in heat and the mechanical inefficiencies of converting reciprocating motion to rotation. Lead-acid batteries become damaged if we routinely discharge more than half of their capacity. During charging, they’re slow to take the electrons we could deliver.

Lithium batteries are comparatively full of promise. Their power density is far greater than that of lead-acid batteries, meaning they’re much lighter for a given capacity. They’re capable of being deeply discharged, which means you can use far more of the bank’s capacity, not merely the first half. And they accept a charge much more quickly; compare that to several hours a day running an engine to keep the beers iced down.

But the pitfalls? Let’s start with ABYC TE-13, Lithium Ion Batteries. Some of its language is bracing. “Lithium ion batteries are unlike lead-acid batteries in two important respects,” the report says. “1) The electrolyte within most lithium ion batteries is flammable. 2) Under certain fault conditions, lithium ion batteries can enter a condition known as thermal runaway, which results in rapid internal heating. Once initiated, it is a self-perpetuating and exothermic reaction that can be difficult to halt.”

Thermal runaway? Difficult to halt? Self-perpetuating?

“Typically, the best approach is to remove heat as fast as possible, which is most effectively done by flooding the battery with water,” TE-13 continues, “although this may have serious consequences for the boat’s electrical systems, machinery, buoyancy, etc.”

If you were following the news in January 2013, you might remember the ­story of Japan Airlines Flight 008. Shortly after landing at Boston’s Logan Airport, a mechanic opened the aft ­electronic equipment bay of the Boeing 787-8 to find smoke and flames billowing from the auxiliary-power unit. The fire extinguisher he used didn’t put out the flames. Eventually Boston firefighters put out the fire with Halotron, but when removing the still-hissing batteries from the plane, one of the ­firefighters was burned through his ­professional protective gear.

Samsung Galaxy cellphones, MacBook Pro laptops, powered skateboards—in the past decade, these and other devices have been recalled after their lithium batteries burned up. In that period, several high-end custom boats were declared a total loss following failures from lithium batteries. In March 2021, a 78-foot Norwegian hybrid-powered tour boat, built in 2019 with a 790 kW capacity battery bank, experienced thermal runaway that kept firefighters on watch for several days after the crew safely abandoned the ship.

Yes, experts are learning a lot about how to mitigate the risks around lithium batteries. But we’re still on the learning curve.

ABYC’s TE-13 “System Design” section starts, “All lithium-ion battery ­systems should have a battery ­management system (BMS) installed to prevent damage to the battery and provide for battery shutoff if potentially dangerous conditions exist.” It defines a bank’s “safe operating envelope” according to such parameters as high- and low-voltage limits, charging and discharging temperature limits, and charging and ­discharging current limits.

Graham Balch takes these safety recommendations a step further: “To our knowledge, the BMS has to monitor at the cell level. With most batteries, the BMS monitors at the module level.” The difference? “Let’s say you have 24 cells inside the battery module, and three of them stop working. Well, the other 21 have to work harder to compensate for those three. And that’s where thermal events occur.”

Balch followed the story of the Norwegian tour boat this past spring. He believes that the battery installation in that case didn’t meet waterproofing standards: “The hypothesis is that due to water intrusion, there was reverse polarity in one or more of the cells, which is worse than cells simply not working. It means that they’re actively working against the other cells. But if the BMS is monitoring only at the module level, you wouldn’t know it.”

On the Green Yachts website, Graham lists five battery manufacturers whose BMS regimes monitor at the cell level. “If I were sailing on an electric boat, whether it be commercial or recreational, I would feel comfortable with having batteries from these five companies and no other,” he said.

The broader takeaway for today’s sailors is that lithium batteries bring their own sets of problems and solutions, which are different from those of conventional propulsion and power-supply technologies. A reasonably skilled sailor could be expected to change fuel filters or bleed a diesel engine if it shuts down in rough conditions. With lithium-ion batteries aboard, an operator needs to understand the causes and remedies of thermal runaway, and be ready to respond if the BMS shuts down the boat’s power.

Real-World Electric Cruising Boats

When we met Oceanvolt’s Derek Rupe a year ago, he and his wife had taken their all-electric boat to the Bahamas and back the previous season. Before that, he’d been installing electric-propulsion packages for six years on new Alerion 41s and other refit projects. “My real passion is on the technical side of things—installations, really getting that right. That’s half the picture. The technology is there, but it needs to be installed correctly.”

When talking to Rupe, I immediately encountered my first learning curve. I posed questions about the Oceanvolt system in amps and amp-hours; he responded in watts and kilowatt-hours. This was yet another example of the different mindset sailors of electric boats need to hold. Why? Because most cruising boats have just one or two electrical systems: DC and AC. The AC system might operate at 110 or 220 volts; the DC side might operate at 12 or 24 volts. On your own boat, that voltage is a given. From there we tend to think in terms of amps needed to power a load, and amp-hours of capacity in our battery banks. Going back to basics, the power formula tells us that power (watts) equals electrical potential (volts) times current (amps). If your boat’s electrical system is 12 volts and you know that your windlass is rated at 400 watts, it follows that the windlass is rated to draw 33 amps.

But an all-electric boat might comprise several systems at different voltages. A single battery bank might supply cabin lights at 12 volts DC; winches and windlasses at 24 volts DC; the propulsion motor at 48 volts DC; and an induction stove, microwave and television at 110 volts AC. A DC-to-DC power converter steps the voltage up or down, and an inverter changes DC to AC. Instead of translating through all those systems, the Oceanvolt monitor (and Derek Rupe) simply reports in watts coming in or going out of the bank.

“We keep all our thoughts in watts,” Rupe said. “Watts count in the AC induction. They count in the DC-to-DC converter. They count the solar in. They count the hydrogeneration in. And the ­power-management systems tracks it that way for shore-power in.

“On a boat like this, maybe I have 500 watts coming in the solar panels,” he continued. “So then I can think: ‘Well, my fridge is using 90 watts. My boat has an electric stove. When I cook a big meal, I can see that for every hour we cook, we lose about 10 to 12 minutes of our cruising range.’”

During his Bahamas cruising season, Rupe observed that on days that they were sailing, the combination of solar panels and hydroregeneration supplied all the power he and his wife needed. “When we weren’t sailing,” he said, “we found that we were losing 8 percent each day, in the difference from what the sun gave us to what we were using for the fridge, lights, charging our laptops, and all that stuff.”

Rupe’s solution? “Twice in Eleuthera and once outside Major’s, we went out and sailed laps for a couple of hours because the batteries were below 30 percent of capacity. It was good sailing, and the wind was coming over the shore, so we didn’t have any sea state. We did a couple of hot laps on nice beam reaches, and generated about 700 watts an hour.”

Of the three sailors Rupe touted in October 2020—Alex Thomson, Jimmy Cornell and the Sailing La Vagabonde couple—only Cornell can report back on his all-electric experiences with Oceanvolt. Alex Thomson ended his circumnavigation abruptly last November, just 20 days after the Vendée Globe start, when Hugo Boss collided with an object in the South Atlantic. And at press time in early fall 2021, Riley and Elayna had just recently announced the build of their new Rapido trimaran; keep an eye on their YouTube channel for more about their experiences with the Oceanvolt propulsion system.

As for Cornell—circumnavigator, World Cruising Routes author, creator of the transoceanic rally, and veteran of some 200,000 ocean miles—he suspended his planned Elcano 500 round-the-world expedition solely because of the Oceanvolt system in his new Outremer catamaran. His Aventura Zero Logs on the Cornell Sailing website, particularly the Electric Shock article posted on December 2, 2020, are essential reading for any sailor interested in sailing an electric boat. “Sailing around the world on an electric boat with zero emissions along the route of the first circumnavigation was such a tempting opportunity to do something meaningful and in tune with our concern for protecting the environment that my family agreed I should do it,” Cornell wrote. “What this passage has shown was that in spite of all our efforts to save energy, we were unable to regenerate sufficient electricity to cover consumption and top up the batteries.”

Cornell’s experience in that article is raw, and his tone in that moment bitterly disappointed. We recommend it as essential reading—not as a final rejection of the electric-boat concept or of Oceanvolt’s system, or even as an endorsement of Cornell’s own decision that the system didn’t work. I suspect that I may have arrived at the same conclusion. Yet given the same boat in the same conditions, one imagines that a new breed of sailor—a Graham Balch or a Derek Rupe—may have responded differently to the constraints imposed by an all-electric boat, as nearly every cruising sailor today habitually responds to the inconvenient constraints of diesel engines and lead-acid batteries.

“If you bring electric winches, electric heads and an induction stove, and then sail into a high-pressure system, you’ll set yourself up for failure,” Balch said. “You have to balance your power inputs and your power outputs.

“Sailing an electric boat is a return to the tradition of sailing that the crutch of a diesel engine has gotten us away from,” he added. “Magellan’s fleet got all the way around the world, and they didn’t have a diesel engine.”

Tim Murphy is a Cruising World editor-at-large and ­longtime Boat of the Year judge.

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