Hallo Klaus Riecken,
WISMAR (Wyssemere). this place is mentioned from 1300(s) in the English archives - it was a busy trading port from northern Europe down to South Africa. Also it is/was a strategic port with fortifications. From 1714-17 onwards there were many political negotiations between countries of who should rule the area - the Russians and Prussians were pressing for Denmark to participate in the demolition of the fortification of Wismar.
SHIPS: I cannot find a list of ships which sailed to Wismar except this ship/brig named 'Fortuna' which made many journeys Covering dates 1814-1842, maybe your Kruger sailors were part of the crew:-
The Brig FORTUNA sailed to WISMAR, 1806: General and Medical Staff, Royal Artillery and Engineers, Gunners, Drivers, Civil Branch of Ordnance, Commissariat, Naval Staff, Officers and Seamen, 20th Light Dragoons, 1st, 2nd, 24th, 38th, 54th, 60th, 83rd, 93rd Regiments
Also, the Dutch ships called into Wismar in 1810 :
Ship's names:- Vrouw Lietske; Goede Trouw
Port(s) of departure: St Petersburg; Surabaya Destination(s): Wismar; Bordeaux Type of voyage: Baltic; East Indies Particulars: The Goede Trouw under Captain Taco Bakker sailed from Surabaya in 1810; ship's inventories, signal book, journals, poems, letters
East LONDON:- STEPNEY is on the banks of the river and was a very busy port in the years you mention. This website describes all the nationalities :
http://www.eolfhs.org.uk/parish/st_george.htm it also has a photo of St. George in the East Church and describes the life of the people. Stepney ALSO had a German Lutheran church for a short while as well as other religious places of worship for the Catholics and the Jews.
ST. GEORGE IN THE EAST Church: If you think the pastor/vicar did not write 'Kruger/Krueger' correctly you can look through the full church list: Hugh Wallis's Genealogical Web Sites
click on ENGLAND, which brings you to this page:-
http://freepages.genealogy.rootsweb.com/~hughwallis/IGIBatchNumbers/CountryEngland.htm#PageTitle
Click on LONDON N-Z
On the next page click on "S" and look for "St. George in the East" and/or STEPNEY
Then from the 'M'(marriage) and 'C' (christening) numbers choose the years and click
This will bring up a separate page - do not enter a name - 'Click' on SEARCH. All the marriages/christenings (baptisms) will be listed in alphabetical surname order.
You can cut down the numbers in the list by entering a given name - but if it has been entered incorrectly it will be missed.
SUGAR REFINERIES were in every port: Many German people worked in these places intro - click on LONDON,
then click on "Stepney": Locations
DIRECTORIES: There were some other Kru(e)ger(s) in London who did not live in Stepney - one was a shipping agent and another imported Madeira wine - you can find them on-line using "Keyword" in the LONDON directories from 1800 onwards : http://www.historicaldirectories.org/ (maybe the John Kruger in the directory was a son of the first John Kruger).
WAACK: I did not find this name in the directories - maybe he used a different name for his business. This name would have the spelling "Wark" in Britain and is found in the seaports of England and Scotland.
This website has some history of 1857 which mentions Wismar, unfortunately it is written in old English grammar :- http://www.marxists.org.uk/archive/marx/works/1857/russia/ch02.htm
Maybe another lister knows of a book which will have more information.
Best Wishes,
Rena in England