Depth exploration of the Channel before WWII? This's update

[elthesalmon]

Here's a rough quantity result I've counted for the hand-written marks/notes on this chart. They aren't final conclusions and unavoidably double check.
*pictures included:

Late 19c hydrographic map collection

One of my cartography collections this's an interesting antique working hydrographic map/chart of English Channel. Printed on very large paper in late 19c. See section picture below there're pencil marks hand-written by its former owner(s). Not cargo shipping plan or route, private sounding...

www.treasurenet.com

In section1/3 I've given about 20 to 30 then finally I got more then 130 totally excluding those vague, almost faded or damaged with missing pieces. generally they're detected soundings in a quantity of 120+ with notes in phrases to short sentences, unknow cross and extended frames from areas. Earlier I thought they're typical depth recorrects until comparison with historic official-survey samples and working modern charts, many of the "crucial" numbers on this one mismatched shallower.
Perhaps no treasures here but mariners' self-survey events, who knows...? I'll steal time for studying more details. Here if you're interested in viewing closer to the sections you want I have many photos, email me freely or direct message on TN. (I consider you won't send trash! :-))

 

[elthesalmon]

Upd and what to do. compared with UKHO wrecklist, no significant infos found.. what's written beside the single cross remains unknown for now. it's (Log[sounding symbol][sounding number]). it should be a logbook for detailed reference but I'm unlikely to contact with the former owner, no reply.
plus ts we(with my friend)'ve pulled runes & remote-sight to view the events and experiences by the surveyors or users. we got similar even the same results performing a historic " damaged victory". waiting for the test.