There is certainly no evidence of 'non-UKHO' TSDPs in Navionics for the area of the Thames Estuary that I can see. But 'other sources' will only be very localised and I think it is only the National Authorities that Navionics could practically approach. I understand that the UKHO 'hope' that such data is shared with them. For the past year, work has been undertaken to collect data for preparation for the New Nuclear Power Station on the Dengie Penisula, the Port of London Authority has oudles of data about the Thames and the Estuary and we can be sure the Wind Farm peeps collected data. There are sources of other tidal stream data. It was obvious that no funding could be available to answer the question. I won't bore you with the reason for the question but the answer was ' there is no data for that area'. I also had an email conversation with the UKHO about tidal stream data: I asked whether there was data for a particular location where currently there was no diamond. The UKHO passed on the query to the French but I got no reply. I queried data in a diamond in the English Channel and the UKHO responded saying the data originated from the French. But not all diamonds on an Admiralty chart are sourced by the UKHO. Other positions must have been subject to specific research many, many years ago. So I reckon we can guess where that data was collected. For example in the Thames Estuary the position of many of the tidal diamonds coincide where Trinity House used to have Lightships. I have a small library of old charts, pilot books etc so you can get an idea of where the data goes from. Not that anything about that is relevant.īut I reckon the answer to your question about TSDPs is 'probably most from the UKHO from the time Navionics started'. I always used the term 'Tide Diamonds' but I just looked up the UKHO technical term - "Tide stream data position". Tide stream data not tide table data so we wasn't thinking about the right thing. You can contact us for more information on Queensland tides.Ah.