Hallo Jan-Dup,
We have done it end May 12 - I know not recently.
The Bloukrantz crossing was extremely easy - virtually "dry-foot" so to speak - mainly because (very important):
We timed our walk to reach the crossing at least 45 minutes before low tide - we left ourselves 5 hrs 30 mins to get there - we are rather slow walkers to take in everything, otherwise we'll have to "run" - not nice!- we got there in 5 hrs 20 mins.
Blombos?? (not aware of a Blombos on the Otter) - do you actually mean Elandsbos? - not a difficult crossing at all - just make sure you pick up the trail
after the "crossing" at the right place - it is (as you reach the Elandsbos) to the extreme right on the opposite bank from you entered the Elandsbos.
The Lottering crossing this time around was more difficult (although also easy) than the Bloukrantz because of the tide.
Enjoy enjoy enjoy.
Andrè W
PS: To see how dry it really was, check the following link:http://www.flickr.com/photos/34849572@N02/7544553072/in/set-72157627440189722