Narrowboaters don't need Tesco to tell them people use too many plastic bags. If you look in my 20 Answers post below you'll see these bags are one of my pet hates. People discard them, the wind picks them up and when they land on water they sink slowly, waiting for an unsuspecting propellor to pass, then they leap forth and wrap themselves 20 times round the propellor shaft.
You wouldn't think a plastic bag could do much to slow down a boat with a 40 horsepower engine but you'd be surprised. The engine strains, the boat loses speed and the tiller starts to shake. The only solution is to visit the propellor and remove the offending bag. Most narrowboats have a weedhatch which is basically a hole in the bottom of the boat through which you can reach the propellor.
Now a hole in the bottom of a boat, as you all know, is not generally a good idea, but his one is special. It sits at the bottom of a sealed box whose top is above the waterline, so you can take the lid off and reach down into the water without flooding the boat. So far so good, but when the propellor is turning at speed it can fling umpteen gallons per second out of the top of the box and fill the engine compartment with water. Of you are lucky, you only drown the engine. If you are unlucky you sink the boat.
Herbie's weedhatch lid is held on by a substantial steel clamp which at the moment is not to be trusted. That's why this picture of it is taken on our stairs at home rather than on the boat where it should be. My over zealous tightening of same has stripped the thread on the tightening screw so I can't tighten it properly and until it is fixed we ain't going nowhere.
Call in weedhatchcoverclamprepairman!! Well, my friend Pete who has the tools and the skills to sort it. Hopefully this time next week we'll be safe to move again. In the meantime I've replaced the sealing gasket between the box and the lid, so in future I won't need to overdo the tightening of the lid.