Considering an electric outboard motor for your sailboat? On the HOME page introduction, we presented some important principles for a better understanding of outboard motors and what to expect. This is the first of three pages in our step-by-step discussion of how to choose and install the best electric outboard motor for your sailboat.
How to Choose the best
Electric Outboard Motor
As sailors, we enjoy sailing, so boat motors are a convenience to be used when necessary to avoid dangers or to easily leave and return to the dock. Recent improvements in electric outboards provide a welcome alternative to combustion engines. Originally designed as trolling motors for fishing boats, electric outboards are becoming popular for sailboat owners who want clean instant power with less noise and no exhaust fumes.
We strive to provide accurate information about the equipment and how to choose the right motor for your boat and situation. We only recommend products that meet our exacting standards and have a reputation for quality, reliability, and applicability, but please take time to read customer reviews and seller-published specifications. Throughout this site, product links are provided for suggested equipment and clicking on the product image or name-link will give you an opportunity to read customer reviews, ratings, and pricing so you can decide what is best for you*. This site is focused on electric outboard motors for sailboats up to 27ft, and up to 5,000 lb. displacement.
Which motor for my boat?
As previously discussed, boat speed is directly affected by boat hull design, displacement weight, wind, waves, and boat motor power. When it comes to motor power, diesel and gas-powered engines provide their rated horsepower only at a specific and very narrow rpm range. That’s why gasoline engines have multiple gears: to keep the motor running in the optimum rpm range where it can provide the rated power. On the other hand, electric motors can provide roughly the same power throughout the rpm range from very slow to fast. Gas and diesel engines measure power in horsepower (rated at a specific rpm), but electric outboards are usually rated in pounds of thrust, or simply "thrust". There is not a simple direct comparison between horsepower and pounds of thrust. Electric outboard motor manufacturers each have a slightly different comparison based on motor efficiency and prop design.
How much power do I need
West Marine, in a West Advisor article by Tom Burden, "Get the Right Size Trolling Motor", recommends five pounds of thrust for every 200 pounds of a vessel’s gross weight1. Minn Kota says, on their website, “...at least 2 lbs of thrust for every 100 lbs of boat weight when fully loaded.”2 So, assume for a 2000-pound boat, fully loaded, the minimum motor power rating would be a conservative 50 lb/thrust. When in doubt, more power is better. Here are our minimum motor thrust suggestions for some boat displacement sizes:
16 ft, 1500 lb disp 40 lb/thrust
18 ft, 2200 lb disp 55 lb/thrust
20 ft, 2400 lb disp 60 lb/thrust
22 ft, 3200 lb disp 80 lb/thrust
24 ft, 4000 lb disp 100 lb/thrust
26 ft, 5000 lb disp 125 lb/thrust
Another consideration is motor shaft length. When under way, the prop should be at least ten inches below the water line. Measure the distance from the water line up to where the motor shaft starts (just below the motor "head") and add 12 inches to get your recommended minimum shaft length. Along with motor shaft length, consider how you will mount the motor: directly on the transom or with a movable motor mount that lets you to raise and lower the motor. My Minn Kota Riptide Rt80/s has a 42" shaft and works well with my Laguna Windrose 18 (25 inch sitting freeboard) as it did with my Chrysler 22. With both boats, I used a motor mount that lowered the motor into the water by ten inches. Get a motor mount with plenty of vertical lift range. Consider the Garelick/EEz-In Motor Bracket.
Popular Electric Outboard Motors
|find on Amazon*
|45||12||42 /50||36||23||Minn Kota Endura MAX 45|
|45||12||42 /50||36||24||Minn Kota Riptide 45/SC/T|
|46||12||40 /50||30||20||Newport Vessels NV-Series 46lb|
|55||12||52 /60||30||23||Newport Vessels 55|
|55||12||50 /60||42||27||Minn Kota Riptide 55/T|
|55||12||50 /60||42||Minn Kota Traxxis 55 SC|
|80||24||56 /60||42||41||Minn Kota Traxxis 80|
|86||24||48 /50||40||26||Newport Vessels 86|
|1 hp||24||45 /50||36||38||Minn Kota EO Electric 1-HP Outboard|
|112||36||52 /60||52||62||Minn Kota Riptide 112/ST|
|115||24||84 /90||24.6||34||Torqeedo Cruise 2.0 RS|
|189||48||84 /90||24.6||36||Torqeedo Cruise 4.0 RS|
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Motors Page ReviewThis page presented some guidelines to help you choose an electric outboard motor that delivers your desired "pounds of thrust" for your specific boat. Electric motors have power requirements such as volts and current (amperes) so on the next page we will help you choose the right battery for your motor and sailing style.
After considering numerous postings by sailors sharing their experiences, as well as my own experience, I offer the following observations:
1.) There is no single rule or equation that clearly and accurately compares electric outboard motor "pounds of thrust" equivalents to gas or diesel motor horsepower ratings. Therefore, we rely on the experience and advice of other sailors, but more power is almost always better.
2.) More power is a trade-off due to increased weight of the more powerful motor and the batteries required.
3.) Buy a motor rated for saltwater use, even if you don't plan on using it in the sea. It will be more resistant to corrosion and you never know when you might take it to the ocean.