Tide Clocks

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prv

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The ones with a hand that goes round slightly slower than once a day - like this one: http://www.marinecompasses.co.uk/Cl...Matt-Chrome/matt-chrome-latch-tide-clock.html

Do they work adequately? Obviously I'm not going to use it to predict to the minute when I should cross some river bar or harbour sill, but as a rough guide? Do the inaccuracies remain about the same, or do they accumulate over time until it's completely wrong and needs to be put back into sync? Will Southampton's slightly unusual tides bugger it up?

I need to buy a new clock and barometer for Ariam as the existing ones are really cheap and nasty (the barometer collapsed inwards into a heap inside its case the first time I touched it) and I thought it might be handy to get a clock with a tide hand as well as the time.

Cheers,

Pete
 
Hi Pete, if it helps any, my parents bought me one for my 50th birthday, still going strong only on its 3rd battery in 8 years, Our tides here in Westernport (Vic Aust) are similar if I remember correctly to those you've queried. I've only reset the clock 4 times. didn't wait till a full moon either, on average it's pretty well spot on but but as recomended I allow for a 30min error, as with our fast tide falls 30 mins can leave you with the "plug pulled out" and nowhere to go for 12 hours, cheers Peter
 
I've got one at home and one on the boat. As a general guide as in, are we roughly on the flood or ebb, nearer low tide or high tide, they work well if set to a standard port - I set mine to Portsmouth. There is an optimum time to set them, I forget when but it will be in the instructions. The accuracy varies to a degree throughout the cycle, going out and then coming back in, I haven't touched mine for a year or more though. Just accept them as a rough guide within an hour or so to show a trend and leave them alone - don't think you can get any improved accuracy by adjusting them all the time.
 
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I have a watch with a 'tide graph' display, which seems fairly consistent over the the 5 years I have had it. It only shows tide state in quarters, but it usually is showing High Tide about the right time. I also have a Tide clock, which although it may be up to an hour out at times, stays remarkably consistent over a longer time, and rarely needs adjusting.
 
l'escargot said:
I've got one at home and one on the boat. As a general guide as in, are we roughly on the flood or ebb, nearer low tide or high tide, they work well if set to a standard port - I set mine to Portsmouth. There is an optimum time to set them, I forget when but it will be in the instructions. The accuracy varies to a degree throughout the cycle, going out and then coming back in, I haven't touched mine for a year or more though. Just accept them as a rough guide within an hour or so to show a trend and leave them alone - don't think you can get any improved accuracy by adjusting them all the time.
Click to expand...

http://www.terrycassell.com/tide-clock-accuracy/
 
I have one which works extremely well and I am very pleased with it.
It keep it set to Dover which makes finding the right page in the tide atlas easy.
It is rare that I have to change the setting but I do check it against the almanac. Experience suggests it is sufficiently accurate for several weeks at a time.
The hand that indicates the tide is a mid blue colour, the hour and minute hands are black. A careful look is necessary in poor light conditions.
 
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l'escargot said:
Just accept them as a rough guide within an hour or so to show a trend and leave them alone.
Click to expand...

Yep, that's the general idea. I have any number of electronic and paper means of getting precise data, just want a general guide on the bulkhead I can glance at.

Glad to hear from a fellow Solent dweller, as Reeds considers our tides to be odd so I wasn't sure if the clock would cope. Don't seem odd to me, but then again they're what I'm used to :)

Pete
 
We have one on the boat as a rough guide and works great for knowing when to turn round and head back in. Obviously isn't any good for predicting tide at a destination if its long way off but for local sailing is perfect for a glance rather than pawing over tide tables.
 
Our boat used to be on a swinging mooring - it was always nice to glance at the clock on the hall wall at home and know which way the boat was facing!
 
prv said:
Yep, that's the general idea. I have any number of electronic and paper means of getting precise data, just want a general guide on the bulkhead I can glance at.

Glad to hear from a fellow Solent dweller, as Reeds considers our tides to be odd so I wasn't sure if the clock would cope. Don't seem odd to me, but then again they're what I'm used to :)

Pete
Click to expand...

Tide clocks track the M2 tidal constituent, which is by far the biggets tidal element for most UK (and many other) ports. Depending on how accurately the clock can tick at 12h32m14.16s (more decimals available on request) it will give an average reading that should not need adjusting.
However:
1. You set it for a port. It needs resetting for another port
2. Neap tides are normally earlier than spring tides (they're not exactly 6 hours apart). The amount depends on the location, but it can easily be half an hour or more.
3. Rise and fall rates are not the same. Dover's last spring (27/5), for example, had a rise time of 4:39 and a fall time of 7:42. Next neap (2/6) will be rise 5:20 and fall 7:08.
4. I expect you'll get very poor results for Southampton (The neap lag is often over an hour, rise time is longer than fall time, at neaps it can be 4 hours longer (8:19 rise, 4:19 fall on 2/6))

For all that, they can be useful for an 'at a glance' guide.
 
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