Blowing the locks

Philip Stanley wrote:I have another question regarding the lock system that might be introduced here:
To wit, what were the pumps for? I've read descriptions of canal locks and systems in the real world, in the USA, Britain, Panama, etc., and none of them used pumps. In all cases, the lock is filled and emptied by opening valves; filled by opening a valve to the upper water level, and emptied by opening a valve to the lower water level. In no case is any pump involved.
Can anyone explain RWC's reference to pumps?
Philip Stanley

the water flowing out of the higher level section must be replaced eventually or that level dries up. Pumps are not necessary if there is a sources of water that flows into that higher level section. If the only water available is at a lower level than that section, it must be pumped in.

At least that has been my understanding.

Everything I've read about canals is pretty clear that they didn't use pumps, but depended upon naturally occurring rivers and lakes at a higher level. Sometimes, as in the case of the Erie Canal, water was brought by aqueducts from miles away th replenish the water in the upper level.
The pumps available on Safehold would have been inadequate to move the large volumes of water constantly being withdrawn from the upper level and transferred to the lower. The available pumps would have been wind-powered or animal-powered, neither of which would have had adequate water-moving power.
So, again, what were the pumps associated with the locks for?
Did RFC just assume that if there was water, there must have been pumps, without really understanding the full dynamics of canals/locks?
Philip Stanley

In RFC's case, that would be atypical.

It may be as simple as the pumps are for the hydrolic opening and closing of large gates and valves.

Blow the what serves for caps on the fill lines and you will drain the upper water slowly. Since flowing water is one of the most destructive things known you could blow all but the top damn segments on the highest set of locks and blow the capping system (or pumps), it would eventually flow all the water from the higher segment out, but would give the ironclads plenty of time to get to the next lock set.

Philip Stanley wrote:Everything I've read about canals is pretty clear that they didn't use pumps, but depended upon naturally occurring rivers and lakes at a higher level. Sometimes, as in the case of the Erie Canal, water was brought by aqueducts from miles away th replenish the water in the upper level.
The pumps available on Safehold would have been inadequate to move the large volumes of water constantly being withdrawn from the upper level and transferred to the lower. The available pumps would have been wind-powered or animal-powered, neither of which would have had adequate water-moving power.
So, again, what were the pumps associated with the locks for?
Did RFC just assume that if there was water, there must have been pumps, without really understanding the full dynamics of canals/locks?

Philip Stanley

On the Miami-Erie in Ohio, the locks used sluice gates in the Doors to raise and lower the water and The whole system was "pressurized" by building a damned lake (Lake St. Mary's - the largest man made lake in the world when built) at the highest point to provide water for the whole system without the need of local pumps to top off individual sections from local water supplies. (The 2nd Northern-most side cut of the Miami-Erie system is 100 feet from my office, and I grew up playing in the locks in Maumee, Waterville and Providence.)

The port that they managed to hold out at, that they eventually evacuated. How damaged are the locks and canals there. From the land advance front, the canals are damaged and take time to repaire, so reaching hte lakes the church are based from will be tricky. So if they plan to retake the ort, to give them a closer position to go after the lakes, while their main army advances along the canal as they secure and fortify it.

You are probably both overestimating the traffic on some canals and underestimating the efficiency of Safehold waterworks and their motive sources. The biggest issue in any canal system is the upstream water supply - too much, BTW, can be as serious as too little - and even partial reuse of the water run through the locks can make an enormous difference. The pumping station needn't have the capacity to operate the locks in real time, it only has to be able to move water uphill as fast as it runs down over the length of a day, say, or even, with enough storage upstream and highly seasonal traffic patterns [which we know to be the case on many of these systems]. In the places where pumps are actually needed, flows of tens of gallons per minute will often do the job - and I know no reason to think that Safehold equipment can't meet or exceed that easily. This is not Predynastic Egypt we're talking about, after all.

Philip Stanley wrote:Everything I've read about canals is pretty clear that they didn't use pumps, but depended upon naturally occurring rivers and lakes at a higher level. Sometimes, as in the case of the Erie Canal, water was brought by aqueducts from miles away th replenish the water in the upper level.
The pumps available on Safehold would have been inadequate to move the large volumes of water constantly being withdrawn from the upper level and transferred to the lower. The available pumps would have been wind-powered or animal-powered, neither of which would have had adequate water-moving power.
So, again, what were the pumps associated with the locks for?
Did RFC just assume that if there was water, there must have been pumps, without really understanding the full dynamics of canals/locks?
Philip Stanley

Hi Louis R,

Thanks for the very good points.

If the pumps primed low pressure siphons, possibly using water as a seal, so the pressure was less than the lower water level, water would be returned to the upper level until the pressure in the pump or siphon equalized or was released.

L

Louis R wrote:You are probably both overestimating the traffic on some canals and underestimating the efficiency of Safehold waterworks and their motive sources. The biggest issue in any canal system is the upstream water supply - too much, BTW, can be as serious as too little - and even partial reuse of the water run through the locks can make an enormous difference. The pumping station needn't have the capacity to operate the locks in real time, it only has to be able to move water uphill as fast as it runs down over the length of a day, say, or even, with enough storage upstream and highly seasonal traffic patterns [which we know to be the case on many of these systems]. In the places where pumps are actually needed, flows of tens of gallons per minute will often do the job - and I know no reason to think that Safehold equipment can't meet or exceed that easily. This is not Predynastic Egypt we're talking about, after all.

Philip Stanley wrote:Everything I've read about canals is pretty clear that they didn't use pumps, but depended upon naturally occurring rivers and lakes at a higher level. Sometimes, as in the case of the Erie Canal, water was brought by aqueducts from miles away th replenish the water in the upper level.
The pumps available on Safehold would have been inadequate to move the large volumes of water constantly being withdrawn from the upper level and transferred to the lower. The available pumps would have been wind-powered or animal-powered, neither of which would have had adequate water-moving power.
So, again, what were the pumps associated with the locks for?
Did RFC just assume that if there was water, there must have been pumps, without really understanding the full dynamics of canals/locks?
Philip Stanley

That's one possibility.

It occurs to me that people may be envisioning works on the scale of the Welland or Panama canals - for either of which pumping would indeed be totally impractical even with our current tech - when all it takes to close navigation is a 3-foot shelf of rock in the river bed. Many of the locks could well have lifts of less that 5'. The amount of water involved in cases like this isn't huge.

This is also a system that would lend itself to the installation of lift locks, which actually use only a couple of tons of water for every transit, for the higher steps, although there's nothing in the text to indicate that they are in use. The water requirements for those could easily be met by pumps powered by a water wheel.

PS: my apologies - I notice that I didn't finish the sentence about seasonal traffic patterns in the system, which must have been rather confusing. I was trying to say that if the ponds are available, you can take 6 months to pump the water for 6 weeks of intensive use. Again, the flow rate of the pump is much less than the rate through the lock.

lyonheart wrote:Hi Louis R,

Thanks for the very good points.

If the pumps primed low pressure siphons, possibly using water as a seal, so the pressure was less than the lower water level, water would be returned to the upper level until the pressure in the pump or siphon equalized or was released.

Louis R wrote:You are probably both overestimating the traffic on some canals and underestimating the efficiency of Safehold waterworks and their motive sources. The biggest issue in any canal system is the upstream water supply - too much, BTW, can be as serious as too little - and even partial reuse of the water run through the locks can make an enormous difference. The pumping station needn't have the capacity to operate the locks in real time, it only has to be able to move water uphill as fast as it runs down over the length of a day, say, or even, with enough storage upstream and highly seasonal traffic patterns [which we know to be the case on many of these systems]. In the places where pumps are actually needed, flows of tens of gallons per minute will often do the job - and I know no reason to think that Safehold equipment can't meet or exceed that easily. This is not Predynastic Egypt we're talking about, after all.