I may have an opportunity to go and play out of Lymington next week on Thursday so was doing a bit of prep and calculating tides. Usually, I'm pretty good at working out secondary tides etc, but this one has me baffled!
I have the following for Portsmouth for the day (which is the referenced Standard Port):
(all UTC, so still need converting to BST)
From the almanac, I calculated the HW offset for Lymington as -0085, giving me a HW time of 0914 UTC, or 1014 BST. I also calculated HW as 2.9m.
I was happy at this point, until I decided to verify my calculations!
EasyTide gives HW 1316 BST (2.9m)
VisitMyHarbour gives HW 1217BST (2.73m)
TidesPLanner App gives HW 1310 BST (3.0m)
Berthon Marina gives HW 1111 BST (3.0m)
I accept that tides are not precise calculations and I'm used to being out by a few minutes, but I'm seeing a difference of 1-3 hours here, which is potentially dangerous!
I've tripled checked my figures and calculations and have also checked for corrections to the Almanac, but keep coming back to the same times!
Can anyone help me to understand:
a) What the tide times will REALLY be on Thursday next week?
b) Where I've gone wrong with my calculations?
c) Why the information available online varies so much?
I've attached a scan of my secondary port calculation, in case the error is really obvious!