Candela already builds one of the wildest, transformer-iest speed boats we’ve ever seen, and we’re huge fans. So, when the company reached out to us a few days ago with pictures of a thing that looked like a cross between a Mark 48 torpedo and a Tomahawk cruise missile, we were definitely interested. Meet the Candela C-Pod, the most efficient marine outboard ever made. And — of course! — it’s 100% electric.
“In other boat motors, be it electric or fossil fuel, the motor is typically situated in a box above the waterline, transferring thrust to the propeller through a complicated set of shafts, bearings and gears,” explains Gustav Hasselskog, Candela’s Founder and CEO. “The Candela C-POD gets rid of the gears altogether. Two ultra-compact yet very powerful electric motors … coupled directly to a propeller, which minimizes friction losses. Contra rotating propellers add the benefit of very high propeller efficiency.”
The primary engineering challenge for Candela was in getting powerful enough motors compact enough to make the C-Pod practical. The solution required a re-think of conventional EV motor design, wherein motor volume is driven by torque, rather than power. “Candela opted to increase the rpm and lower the torque to boost the Candela C-pod’s power density,” reads the official, dense press release. “The best way was to split the thrust needed on two propellers. The reason is that the maximum rpm is limited by the speed of the propeller tip moving through water. At around 45 m/s propeller speed, the pressure in the flow around the propeller reaches vacuum and starts to boil … so splitting load on two propellers allows for propellers with smaller diameter and thereby higher rpm – and in turn smaller motors.”
The dummy version is that, if you spin the props too fast, the water around them gets too hot and boils, turning to steam. In order to move a boat forward, though, you need water, not steam, so they figured out the max speed they could spin their prop at and built backwards from there, eventually settling on two counter-rotating propellers that make the boat go fast. As a bonus, the long, narrow EV motor design sort of lent itself to this torpedo look, which is just awesome to see.
So, we know it’s fast, but one other benefit from the Candela C-Pod is its nearly silent operation, even at 30 knots. That means you can now positively blast across the lake in relative quiet and without waking up the neighbors (even if you are “that guy”).
Even with all the fancy engineering and stealthy, go-fast goodness, you’re probably repeating that old bromide about boat ownership to yourself as you read this. The one that goes, “The two best days of boat ownership are the day you buy your boat, and the day you sell your boat.” Not so with the Candela — at least, that’s the promise made by a line in the press release that reads, “Freed from gears and with very few moving parts, the Candela C-POD will last several thousand hours without any maintenance whatsoever.”
As my buddy, Neil, might say: interesting, if true.
What do you guys think? Does the promise of zero maintenance combined with high power make this latest product from Candela a must-buy, or are you looking for something a bit more conventionally shaped from your electric boats and personal watercraft? Better yet, anyone see this and start drawing up an underwater jetpack deal? Let us know in the comments!
Source | Images: Candela.