Products - Electric Outboards

Ahoy, fellow boaters

Sustainable electric propulsion is the core value of electric propulsion systems and protecting our fragile water eco-environment is paramount.

So you think you want to buy an electric outboard. Here are the four steps you need to make to live the dream of silent, clean running.

Decide your Shaft Length - follow step 1
Decide whether you want traditional prop or Rim Drive prop.
Decide how much motor you need to do what you want to do.
Decide how much battery capacity ( range ) you need and want.

STEP 1:

The first step in buying one is to figure what Shaft Length you need. Electric Propulsion systems differ from traditional outboards. here is some help in getting to the right size motor based upon several of the popular items that are out there.

Finding the Perfect Shaft Length: A Boater's Precision Guide

When outfitting your vessel with an electric outboard, the importance of selecting the correct shaft length cannot be overstated. Precision here is paramount, ensuring optimal performance and safeguarding against unwanted mishaps. A shaft too long might still function, but at the cost of performance, with increased risk of striking bottom or submerged hazards like treacherous rocks. Conversely, a shaft too short spells disaster, as cavitation is almost a certainty and dramatically effects range.

Understanding Shaft Length Measurements

Be aware, every manufacturer has a different length for their units and measures shaft lengths differently from gas-powered outboards. For electric outboards, the shaft length is gauged from the top of the clamp bracket to the center or bottom of the propeller. In contrast, gas outboards are measured from the top of the clamp bracket to the anti-ventilation plate.

Comparison with Mercury Outboards:

E-Propulsion XS is akin to Mercury's S, S is comparable to Mercury's L, and the L exceeds Mercury's L in length.

Steps to Determine the Appropriate Shaft Length

Measure the Transom Height: Begin by measuring from the top of the boat transom to the bottom of the boat, as depicted below.

Calculate Minimum Shaft Length: Add the radius of the propeller (found in your user manual and technical drawing) to the transom height to ascertain the minimum shaft length required.
Ensure Adequate Clearance: Add an additional 10 cm (4 inches) to your previous calculation to determine the ideal shaft length, guaranteeing sufficient water flow beneath the boat.

Example Calculation: For the Spirit 1.0 Evo Remote with a propeller radius of 5.5 inches, and a 1964 16’ Starcraft aluminum boat with a transom height of 21 inches, the calculation would be as follows: $21" + 5.5" + 4" = 30.5"$ Thus, a long shaft outboard motor is the optimal choice.

ePropulsion Shaft Length Options:

Spirit Series:

XS: 52.5 cm / 20.7 inches
S: 62.5 cm / 24.6 inches
L: 75 cm / 29.5 inches

Navy Series:

S: 63.4 cm / 25 inches
L: 75.9 cm / 29.9 inches

Shaft Length Recommendations:

Transom Height	Shaft Length
30 cm / 11.8 inches – 40 cm / 15.7 inches	Extra Short*
40 cm / 15.7 inches – 50 cm / 19.7 inches	Short
Higher than 50 cm / 19.7 inches	Long
*Extra short available for Spirit series only.

This chart serves as a general reference to match ePropulsion outboard shaft length with your boat's transom height. For utmost accuracy, follow the three-step calculation method.

Additional Tips for Specific Boats:

For small dinghies and aluminum boats under 15ft or 4.5m, choose between extra short or short shafts based on whether the transom height exceeds 40 cm / 15.7 inches.

For boats with transom heights over 50 cm / 19.7 inches, opt for a long shaft version.

Sailing Boats and Daysailers:

For daysailers and short one-design racing sailboats, the outboard mount's position is crucial. The Spirit 1.0's XS shaft works well if the mount is positioned low.
For sport boats and other sailing vessels, measure the distance from the waterline to the top of your outboard mount.

Always consult your local dealer for recommendations tailored to your boat and local conditions. Should you have further queries regarding shaft length, do not hesitate to reach out on our official Facebook page.

Download the technical drawings for ePropulsion outboards here:

Spirit 1.0 Plus
Spirit 1.0R
Navy 3.0
Navy 6.0

Download the technical drawings for Rim Drive outboards here:

Browse our selection of various electric outboard motors today, and make that electric outboard an essential part of your boating experience.

STEP 2. Choose your propulsion propeller type.

There is a cost-benefit analysis that one must do to determine whether a rim drive or traditional is best for your needs.

	RIM-DRIVE	Center Prop - PLASTIC	Center-Prop METAL
Advantages	Highest Thrust	Lowest Thrust	Medium Thrust
MAINTENANCE	Least Maintenance	Low Maintenance	Low Maintenance
DEBRIS	Good in Icy/Debris filled waters	Worst in Debris/Icy waters	Best in icy/debris filled waters
KELP	Best if lots of kelp or fishing lines
Disadvantages	More Expensive	Less Expensive	More Expensive
OVERPROP	Cannot Over/under prop	Cannot Over/Under prop	Can over/under prop
POWER NEEDED	Most Ffficient	Efficient	More Battery needed
LOCAL SUPPORT	MEDIUM	BEST	POOR

*The choices are not always clear. With the traditional propeller type - center axis, there are now several choices of prop materials. The plastic probs, most common, are fine but do not last as long as metal ones.

STEP 3: HOW MUCH MOTOR DO YOU NEED?

Speed vs range is always a tradeoff in boats, and electric boats are no different, in fact, the trade-off is much greater depending on the design configuration of the boat, sea state, tide and many other factors.

STEP 4: HOW MUCH BATTERY CAPACITY do you have space and budget for?

The good news is you can recharge your batteries for pennies on the dollar at home or at a marina. This means your total cost of running your boat is much less than traditional gas or diesel motors.

The bad news, is you cannot take a jerry can and fill it up with kilowatts. This means your range is fixed at the time of the start of the voyage unless you are like us and bring extra batteries with you. We provide a whole range of range-extension batteries for every electric motor out there.

This means you need to think about how far you are going to want to go at what speed so you can size your batteries appropriately.

STEP 5: ONE VENDOR SOURCE or MIX & MATCH

Now with the above 4 decided, the most difficult step is next. Whether to choose to go with a one vendor solution with the inherent peculiarities of that vendor or mix and match vendors and take the risk that everything does not work together.

For sure single source is always safer, but almost always more expensive and may not have all the features you want all from one vendor. Usually vendor who sell the complete system stand behind their system offer, and hence commercially are easier to troubleshoot and carry less risk.

Please see complete single-vendor solutions here to get an idea of what they cost if purchased as complete turn-key systems. Our experience is about 1/2 the electric propulsion systems installed are sole source, and the other half are mixed vendors.

step 5b: If for any reason, budget or feature, you choose to go with a mixed vendor solution, the issue is just making sure that all the units work together. We have a strong experience doing this, and we only recommend systems that we know have a history of happily working together.