Drunkskunk
100 GW
What is the most efficent form of motored propulsion for a low speed, light weight boat?
I've been planning an E-Kayak for years, but have limited time, and each year my plan gets revised. Its still just a dream. But one of the things I've been wondering about is the drive.
A trolling motor is the easiest answer. its an electric drive designed for exactly what we need. But the efficancy is way low. And I'm not convenced a spinning prop has the potential to ever be efficent.
I had a friend who was the 2nd owner of what had once been the worlds fastest human powered boat. It was a unique design paddle wheel that folded it's paddles flat for best wind resistance, and moved the padles through the water horizontally so they maintained the same speed regardless of depth. That boat flew over the water with just the two of us pedeling.
The designers had chosen an 8 foot tall paddle over a prop for a reason, and had suceeded.
But that can't be the only or best answer. Surely there has to be a better way
In order for a propultion device to be efficent, it needs to transfer energy to the water without moving the water. You want the boat to move in the water, you don't want the water to move. The more you shove, move, or force water in a new direction, the less you move the boat.
So my theory is that Large, slow moving blades are needed, moving in a linear a fassion along the axis of movement. I think that there is a relationship between the blade's surface area and the thrust needed to move the boat that affects efficancy, though I have no idea how to calculate that.
So any thoughts on this?
I've been planning an E-Kayak for years, but have limited time, and each year my plan gets revised. Its still just a dream. But one of the things I've been wondering about is the drive.
A trolling motor is the easiest answer. its an electric drive designed for exactly what we need. But the efficancy is way low. And I'm not convenced a spinning prop has the potential to ever be efficent.
I had a friend who was the 2nd owner of what had once been the worlds fastest human powered boat. It was a unique design paddle wheel that folded it's paddles flat for best wind resistance, and moved the padles through the water horizontally so they maintained the same speed regardless of depth. That boat flew over the water with just the two of us pedeling.
The designers had chosen an 8 foot tall paddle over a prop for a reason, and had suceeded.
But that can't be the only or best answer. Surely there has to be a better way
In order for a propultion device to be efficent, it needs to transfer energy to the water without moving the water. You want the boat to move in the water, you don't want the water to move. The more you shove, move, or force water in a new direction, the less you move the boat.
So my theory is that Large, slow moving blades are needed, moving in a linear a fassion along the axis of movement. I think that there is a relationship between the blade's surface area and the thrust needed to move the boat that affects efficancy, though I have no idea how to calculate that.
So any thoughts on this?