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> That terminology is borrowed from the original practice of having mules haul barges along canals The Panama Canal has mechanical mules, but they are only use

> That terminology is borrowed from the original practice of having mules haul barges along canals The Panama Canal has mechanical mules, but they are only used to keep ships on course, not to propel ships (https://en.wikipedia.org/wiki/Panama_Canal_locks#Mules https://en.wikipedia.org/wiki/Panama_Canal_locks#Mules) Disadvantages of towing are that it requires a towpath alongside the water, that overtaking is difficult, and that making tight turns can be difficult (the puller always pulls the ship closer to the canal or river shore, requiring the use of the ship’s rudder to keep it on track. In tight turns, the pull direction is closer to orthogonal to the shore, requiring more rudder) Because of these, I think battery-powered ships with container-sized batteries that can easily be swapped may be a better solution.

usrusr 4y ago
If you could supply the mules like electric trains are supplied, you might just as well replace the powerful mules with lightweight power pickup runners that the boats connect to with a cord. Boats would only need a few minutes of battery power for situations that aren't as easy as running straight along the canal.
- taneq 4y ago
  At that stage, just have overhead power lines for the boats… might spoil the scenery a bit though.
  - cjrp 4y ago
    Exactly, chuck a pantograph on the boat and it’s job done!
    - usrusr 4y ago
      The difficulty I think is that there aren't many board purpose-built for canals: they are purpose-built for canals and rivers and many navigable rivers are to canals like oceans to the rivers, much wider and unpredictable environment. That also makes that "pickup runner" idea I posted much harder than I first thought, and pulling mules (modern as well as actual). Historical pictures of badge towing show astonishingly long lines, I believe that this is because rivers tend to have wide shallow waters between the part that is deep enough for navigation and the part that is dry enough for a tow-path. The good news is that multimodal boats should work just fine, might even be easy to make the electrified parts support enough autopilot to allow the time to be used below deck for engine maintenance and the like. Barge operation is mostly waiting anyways and getting rid of the last instances of unscheduled interactivity might be really easy (if it hasn't been achieved yet? Primary obstacle is that the market just isn't very big)
  - twic 4y ago
    My guess would be that a wheel on a rail turns torque into force more efficiently than a propeller in water.
WalterBright 4y ago
The mule can travel on an overhead rail, or have mules on each side.
- dredmorbius 4y ago
  Mules on each side compounds the already somewhat problematic passing problem, unless a canal consists of independent channels for each direction of traffic. That's only possible in some cases. For large shipping canals with locks, there may be distinct channels for a portion of the trip. In most cases though canals integrate with river, lake, and sea-based segments which would make that more complex. River-based mule tows would already be quite challenging in most cases.
  - nico_h 4y ago
    "just" install vertical pairs of rails along both side of the canals. top rails goes south. bottom rails goes north. Pulling engine attached to the rail. Have a rule that the bottom rail tethered ship disconnects before crossing incoming vessels. The crew then reconnects to the trucks after passing. Make sure the cable are high enough that other ship can pass under. Or both ships disconnect. Or top rails ship has an arm that lift the slacked cables during the crossing, and the bottom rail ship has an arm that dunks the other cable bellow the incoming ship during the passing. Rail or battery rail powered rail cars (basically an engine and a hooking system) on the rails pull the ship, positioned on the canal. The rail trucks can have big V shape receivers for the crew to throw the tether ends to reconnect without having to stop and come ashore. Of courses you then have to look at the cost and general burden of installing all this infrastructure, maintaining it, ensuring the safety of having the trucks not crushing anything, making sure the boat arms can ensure trouble free crossing. But yay, you save a lot of fuel and it might be more efficient than the boats propelling themselves.
nico_h 4y ago
Or maybe for inland barges have some medium sized batteries, recharged at each lock, where you already have infrastructure, possibly with pantograph. There are already a bunch of these type of projects for buses with quick charge at multiple bus stops across their routes. No need to install thousand of miles of pantographe cables above every canal. If the locks are too far, you can install the overhead lines every 10s of miles, on long straight with clear rules of passing.

usrusr 4y ago

If you could supply the mules like electric trains are supplied, you might just as well replace the powerful mules with lightweight power pickup runners that the boats connect to with a cord. Boats would only need a few minutes of battery power for situations that aren't as easy as running straight along the canal.

taneq 4y ago
At that stage, just have overhead power lines for the boats… might spoil the scenery a bit though.
- cjrp 4y ago
  Exactly, chuck a pantograph on the boat and it’s job done!
  - usrusr 4y ago
    The difficulty I think is that there aren't many board purpose-built for canals: they are purpose-built for canals and rivers and many navigable rivers are to canals like oceans to the rivers, much wider and unpredictable environment. That also makes that "pickup runner" idea I posted much harder than I first thought, and pulling mules (modern as well as actual). Historical pictures of badge towing show astonishingly long lines, I believe that this is because rivers tend to have wide shallow waters between the part that is deep enough for navigation and the part that is dry enough for a tow-path. The good news is that multimodal boats should work just fine, might even be easy to make the electrified parts support enough autopilot to allow the time to be used below deck for engine maintenance and the like. Barge operation is mostly waiting anyways and getting rid of the last instances of unscheduled interactivity might be really easy (if it hasn't been achieved yet? Primary obstacle is that the market just isn't very big)
- twic 4y ago
  My guess would be that a wheel on a rail turns torque into force more efficiently than a propeller in water.

WalterBright 4y ago

The mule can travel on an overhead rail, or have mules on each side.

dredmorbius 4y ago
Mules on each side compounds the already somewhat problematic passing problem, unless a canal consists of independent channels for each direction of traffic. That's only possible in some cases. For large shipping canals with locks, there may be distinct channels for a portion of the trip. In most cases though canals integrate with river, lake, and sea-based segments which would make that more complex. River-based mule tows would already be quite challenging in most cases.
- nico_h 4y ago
  "just" install vertical pairs of rails along both side of the canals. top rails goes south. bottom rails goes north. Pulling engine attached to the rail. Have a rule that the bottom rail tethered ship disconnects before crossing incoming vessels. The crew then reconnects to the trucks after passing. Make sure the cable are high enough that other ship can pass under. Or both ships disconnect. Or top rails ship has an arm that lift the slacked cables during the crossing, and the bottom rail ship has an arm that dunks the other cable bellow the incoming ship during the passing. Rail or battery rail powered rail cars (basically an engine and a hooking system) on the rails pull the ship, positioned on the canal. The rail trucks can have big V shape receivers for the crew to throw the tether ends to reconnect without having to stop and come ashore. Of courses you then have to look at the cost and general burden of installing all this infrastructure, maintaining it, ensuring the safety of having the trucks not crushing anything, making sure the boat arms can ensure trouble free crossing. But yay, you save a lot of fuel and it might be more efficient than the boats propelling themselves.

nico_h 4y ago

Or maybe for inland barges have some medium sized batteries, recharged at each lock, where you already have infrastructure, possibly with pantograph. There are already a bunch of these type of projects for buses with quick charge at multiple bus stops across their routes. No need to install thousand of miles of pantographe cables above every canal. If the locks are too far, you can install the overhead lines every 10s of miles, on long straight with clear rules of passing.