ditchcrawler
Well-known member
Although Shmoo has answered Moodysabre has the same boat as me (M31) & I know to my cost that although the official draught is 1.52m with full tanks I have scrunched the cill at Tidemill when the gauge was reading 1.6 and a bit.I now allow 1.7m on the gauge.Shmoos predictions are good except that you have to watch out for northerlies which can hold the water back a bit & obviously high pressure can make a substantial difference.I have spent some time watching the Tidemill gauge via the webcam(sad git) & often the 2nd high tide of the day is lower in terms of depth over the cill than predicted.There are tides when I cannot get back into the Tidemill in the late evening at springs.As another rule of thumb take 1.5m off the high tide at Harwich & this gives the rough max water over the cill at Tidemill.
My understanding is that one millibar increase in pressure from "normal pressure"
which is 1012/1013 reduces the depth by one centimetre.I.E if pressure is say 1018 then depth reduced by circa 6cm or a bit over 2 inches.
A good site to look at to check current effects is www.pol.ac.uk/ntslf/ which gives the actual real time levels for various places compared to predictions.
My understanding is that one millibar increase in pressure from "normal pressure"
which is 1012/1013 reduces the depth by one centimetre.I.E if pressure is say 1018 then depth reduced by circa 6cm or a bit over 2 inches.
A good site to look at to check current effects is www.pol.ac.uk/ntslf/ which gives the actual real time levels for various places compared to predictions.