What is Thoosa? Thoosa is a range of inboard electric propulsion plug and play systems using Lynch motors and Sigma controllers.
What is E-Propulsion? E-Propulsion is a range of well-built, affordable electric out boards designed for the marine environment.
What is Clean eMarine? Clean eMarine is a Danish company that has developed and tested the Thoosa electric systems worldwide. These systems are now manufactured and assembled in the US.
Why electric? Electric motors are simpler, quieter, cleaner, more efficient, and more reliable than internal combustion engines: no oil, quiet running, low maintenance, clean water, clean engine space, and clean air. The batteries can also be charged from renewable sources (solar and wind) and multiple sources such as shore power, regenerative and/or generator. Electric motors are more maneuverable as you can go from forward to reverse with the flick of a switch, and full torque is available at slow RPMs; there is instant power with no warm up.
How fast will it go? As fast as the internal combustion engine will push the boat. Of course, the closer you get to hull speed, you need exponentially more power.
How far will it go? The definitive answer requires accurate numbers on the length, weight, and speed of the boat, and the size of the battery bank. More generally you can say that a standard battery bank will push the boat at 4 knots for 4 hours, and at full power for one hour. The closer you get to hull speed you need exponentially more power to go faster, so the slower you go the farther you go.
How much will it cost? An electric propulsion system with a standard battery bank costs as much as a new diesel engine, and the installation is generally simpler.
What kind of batteries? The best batteries for a drive bank depend a little bit on the use of the boat. If all the electric motor must do is power in and out of the marina, then a thin plate pure lead agm battery bank is acceptable. If the boat will be away from shore power for extended periods, then you need a battery that does not develop a memory as almost all lead acid batteries do. Neither carbon foam core AGM batteries nor lithium batteries will develop a memory. If weight, power loss at high draw, or charge cycle life are important, the best lithium batteries are LiFePo4 (lithium iron phosphate). They do not catch fire, are half the weight of lead acid batteries, do not lose amp hours at high draw, and they are the cheapest battery by the charge cycle.
Where are the electric propulsion systems installed? We install in Seattle, WA. You can install wherever your boat is.
What propeller is best? Because an electric motor has all of its torque available at any RPM, it cannot get bogged down like an internal combustion engine which needs to be able to achieve full RPM to reach full torque. Therefore, the propeller can be as big as possible since it is generally more efficient to turn a larger propeller slower (750 RPM or below) than a smaller propeller faster below planing speeds. The most efficient propeller pitch is generally considered to be 8 to 10- an 8 inch pitch on a 10 inch prop. The space available for the propeller can limit the diameter of the propeller so that there is not enough pitch to achieve the desired speed with 750 RPMs. You can increase the propeller pitch at least up to a square prop where the pitch is equal to the diameter- a 10 inch pitch on a 10 inch diameter prop, for example. This not only helps keep the RPMs down, but can help get more out of power regeneration off the prop when the boat is under sail.
What of my existing system can I use? The old propeller shaft and propeller can be used because the motor can be geared to match the propeller. It is sometimes possible to adapt the engine mounts.