4 ms·

They use so little because the use the (steel) cable for traction (as I understand it) and not water. If they had to use a propeller in the water to cross a riv

They use so little because the use the (steel) cable for traction (as I understand it) and not water. If they had to use a propeller in the water to cross a river, the consumption would be much more. So in essence, there's symbiosis between electricity and running a cable-guided ferry. Otherwise you'd need more energy, therefore bigger batteries, etc.

algo_trader 4y ago
I really dont think so. There are just crossing 500m at 2-3 knots several times a day. This is basically less than a semi rolling resistance which is maybe 1/5kwh/km? EDIT: even so, x10 batteries 2mwh are still very reasonable for a boat which cycle daily
rz2k 4y ago
When he mentioned the steel cable, I wondered why they don't use an arrangement more like cable cars. It sounded like it is in case they break loose during a storm or emergency, so it useful to have the engine on board along with the back up generators. Are the cables actually used for traction, or just a countermeasure against having to fight the cross current?
- ok_dad 4y ago
  Yea, they pull themselves along the cable. The commenter above you was correct, it is way more efficient than props, plus it's way more efficient for high currents like this river. My comment was simply that they could have used batteries, but for this particular application a cable was perfect. I was reinforcing that this was a great confluence of constraints that enabled this.
- ricksunny 4y ago
  I was also wondering this, you beat me to asking. If there is precedent for two cables why not connect them to make a long narrow loop of them like on a ski-lift; place an electric-powered winch on one end and an idler on the other? Was neat to see the video, and I’m sure they have their reasons.
  - matsemann 4y ago
    One reason may be that the cable sinks to the ground, which makes it possible for other boats to cross. If it was like a ski lift, the cable had to be more tensioned I guess, thus obstructing?

algo_trader 4y ago

I really dont think so. There are just crossing 500m at 2-3 knots several times a day. This is basically less than a semi rolling resistance which is maybe 1/5kwh/km? EDIT: even so, x10 batteries 2mwh are still very reasonable for a boat which cycle daily

rz2k 4y ago

When he mentioned the steel cable, I wondered why they don't use an arrangement more like cable cars. It sounded like it is in case they break loose during a storm or emergency, so it useful to have the engine on board along with the back up generators. Are the cables actually used for traction, or just a countermeasure against having to fight the cross current?

ok_dad 4y ago
Yea, they pull themselves along the cable. The commenter above you was correct, it is way more efficient than props, plus it's way more efficient for high currents like this river. My comment was simply that they could have used batteries, but for this particular application a cable was perfect. I was reinforcing that this was a great confluence of constraints that enabled this.
ricksunny 4y ago
I was also wondering this, you beat me to asking. If there is precedent for two cables why not connect them to make a long narrow loop of them like on a ski-lift; place an electric-powered winch on one end and an idler on the other? Was neat to see the video, and I’m sure they have their reasons.
- matsemann 4y ago
  One reason may be that the cable sinks to the ground, which makes it possible for other boats to cross. If it was like a ski lift, the cable had to be more tensioned I guess, thus obstructing?