Tides are funny things.
Us salty seadogs pore over the tide tables and do complex sums (or cheat and use an app!) to determine whether there will be enough water to go where we want to go when we want to go. The trouble is, Old Mother Nature doesn't read the tide tables!
Any number of factors can affect just how high (or low) a tide actually gets on the day and the predictions are not by any stretch of the imagination infallible
Right now I really need to get Pagan back onto her mud berth on this cycle of spring tides* which starts to tail off tomorrow. We need at least 5.0m of tide, preferably over 5.1 to be sure of getting on or off our berth. Any less and the keel will be in the mud which would be fraught with all sorts of undesirable possibilities
Yesterday afternoon the tide was predicted to be 5.1m. However, a combination of relatively high atmospheric pressure (tide tables are generated assuming a pressure of 1013, we had 1025 yesterday which will depress the tide by several inches) and a stiff Westerly wind keeping the tide back meant we came up several inches short of enough water
With a couple of hours to go today it very much looks as though the same thing is going to happen again. And tomorrow the predicted high tide is 0.1m lower and drops day by day from then on
It's not a total disaster if we can't get on our berth on this tide cycle. We'll just have to stay on the river pontoon for a couple of weeks. I prefer to avoid that though, as we're occupying space that could be used by visitors and swinging moorers, but needs must
* This is a particularly bad cycle for us which doesn't help. The height of spring tides varies cyclically with the second spring tides of each month tending to be significantly higher than the first. They also vary annually and seasonally in a complex way which I don't propose to explain (mainly 'cos I've never really got my head around it all!). Suffice it to say that this set of springs, amongst the lowest we see at Fambridge, is only just high enough if as predicted and it doesn't take much to knock those vital few inches off the tide on the day
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