Dutch or any other locks for that matter

[Daydream believer]

The salt water is at sea level, the fresh water isn't.

Twice a day I doubt that

so presumably that depends on the height of tide at the time
How salt water pushes freshwater back if the fresh water is higher has me bemused- or does that never happen?
If it did not then Holland would jolly soon fill up
I seem to remember when the Veersemere was tidal the water ran out at some thing like 7 Kts in the narrow channels so it must have been lower once
Likewise when one has high tide such that it is higher than the freshwater it will want to flow the other way.
Nothing to do with density me thinks !!!i

 

[Pye_End]

Unless you have to use the commercial locks, big enough to turn around in, reversing out is fun.:encouragement:

+1!

 

[sailorman]

Twice a day I doubt that

so presumably that depends on the height of tide at the time
How salt water pushes freshwater back if the fresh water is higher has me bemused- or does that never happen?
If it did not then Holland would jolly soon fill up
I seem to remember when the Veersemere was tidal the water ran out at some thing like 7 Kts in the narrow channels so it must have been lower once
Likewise when one has high tide such that it is higher than the freshwater it will want to flow the other way.
Nothing to do with density me thinks !!!i

The Dordtsche Kil & Spui are still tidal

 

[AngusMcDoon]

Twice a day I doubt that.

For a very short length of time unless the locks are free flowing for a period, in which case the direction of flow will be determined by what the tide is doing. Free flow is common in a lock going into a restricted harbour basin where the level in the basin can rise and fall, but not so common going into a canal system where the level cannot be allowed to rise and fall.

 

[sailorman]

For a very short length of time unless the locks are free flowing for a period, in which case the direction of flow will be determined by what the tide is doing. Free flow is common in a lock going into a restricted harbour basin where the level in the basin can rise and fall, but not so common going into a canal system where the level cannot be allowed to rise and fall.

The Dutch do not "do" free-flow they control their waterway system

 

[AngusMcDoon]

The Dutch do not "do" free-flow they control their waterway system

I mean when both gates of a lock are open simultaneously. I'm sure the Dutch do not call it free flow, they will call it something in Dutch. However, that doesn't mean they never do it as part of their controlling their waterway system. For controlling their waterways no-one is better at it than them.

 

[Fossil]

Let's not get too carried away by the whys and wherefores of the fresh/salt water management systems - they are operative in only a few places anyway.

From the boatie's point of view, all you have to do is get into the lock when you get the green light, secure the vessel properly and wait until you get the green to go out. The lockmaster will do all the technical work. My point was merely that, if you don't get the green immediately you get to the level, there may be something else going on, so be patient.

And in years of travelling around the Dutch canal and inland water systems, we never encountered a lock where the currents were strong enough to worry about, provided the lines were properly tended. And the rise and fall is nothing to worry about. Usually quite small, and where the locks give out to the sea, where a +- 3m change might be expected, you often get a floating captive pontoon to tie up to. Or cables stretched from top to bottom to hold your lines. As I mentioned before, sailing is a mass-participation sport in Holland and every effort is made to make things easy and simple for its participants. How utterly unlike the UK... but that's another thread, I guess.

 

[AngusMcDoon]

It's a long sail from Paekakariki to Cloglandia. You can't exactly pop over for the weekend. I've never had a strong current in a cloggy lock either. Monster barges scraping past at high speed a couple of feet away is another thing though. Eek! Something else that catches out canal noobs is thwacking the top of the mast on an overhanging tree. You just don't expect a sailing boat's mast to hit trees.