Not the sort you smoke, but the wet, green stuff is making its presence felt, particularly in the approach to Hoorn in the Markermeer.
Boats have reported picking up great lumps of sea weed on their propellers, only noticing the problem when their speed through the water was severely reduced or the propellers were juddering. This has also been reported as being problematical in the approach to Edam, Volendam and Marken. The problem seems to be an ongoing one with numerous boat reporting similar issues in 2017 and 2018 and the harbour at Hoorn closed to boat movements on occasion whilst the weed was cleared from the entrance.
Some boats have managed to clear it whilst underway by going sharply astern for a short burst, whilst others have had to resort to donning a wetsuit and investigating underwater.
You have been warned!
Many thanks to but4thegrace.blog for the photo