Floating trees...............and killer wales?

1847 As we set off this morning at 0900, we instantly got caught up in something and had to work the prop in forward & reverse to clear it. We were off to a flying start again in the still fast flowing river which swept us along under the bridges we struggled to pass yesterday coming upstream. I'd cleared some weed & twigs from the engine cooling water strainer before we set off which somehow caused the breathers on the shaft seals to pump loads of water out, filling their little containers and flooding the bedroom floors, as when I tightened the strainer a bit more it stopped. Normally the boat sails along in a fairly straight line, just needing small inputs to keep on course, but in this river it continually tries to go sideways and it's a real effort to keep on track - as well as dodging the trees & logs all floating along with you. At one point I saw a big black fin sticking out of the water coming straight at me with a "v" shaped turbulance streaking out behind it. Just as I thought we were being attacked by a killer whale, the big red body of the channel marker with a black fin shaped radar reflector popped up for a second and then was dragged back under and I realised it was chained to the bottom and it was me heading for it. We swerved just in time! We passed about ten boats coming up stream through the day, all fairly big power boats and all except the two that were planing at about 30mph made gestures how slow the progress was for them. Towards dinner something became wrapped around the port prop that we couldn't shake off, so we swapped to the starboard side, still making over 7kts at 1600rpm. A couple of ports that we passed were full so we pulled into the port de pleasance in Macon at 1415 and took a bows too mooring, threading our own line through the floating mooring buoy after floating about for a few minutes thinking how it was all going to work without one of our motors. As it happened, I tried the port motor very slowly and it worked. A few minutes later the wet suit was on and I went under for a look - there were remenants of reed but it must have untangled itself as the prop was clear. The rope cutter worked when I spun the prop with my finger in the wrong place. I checked the rest of the hull which was fine and really clean considering we had long grass growing off us when we left Dover. I think the salt water things must just die off in the fresh water.