This in from Wightlink, in their own words. Ed
Please be advised that unusually low tides are expected between 19-22 March which may result in disruption to the Lymington / Yarmouth car ferry service.
These extreme conditions only occur every 20 years and coupled with atmospheric weather conditions – which results in even lower tides than normal – we anticipate that the service will be disrupted specifically around one hour before and one hour after the low water times.
No disruption is anticipated on the Portsmouth – Fishbourne / Portsmouth – Ryde routes
Wightlink would like to apologise for any inconvenience this may cause.