This has been a huge issue for me. I think using some of the products listed by Sue might help.
If you are paddling on flat water with no waves, a little fog can be easily wiped with a dry lense cloth.
The problems arise in bumpy conditions when you don't have the stability or time to be wiping and fussing. Also, in bumpy conditions, there is a constant spray of water, so even as you're taking a picture, the lense can get wet.
I was just checking out Justine Curgenvens Blog as she is currently doing the Tierra del Fuego circumnav (the same as Marcus Demuth)
www.cackletv.com/justines-blog/
And she has a photo on there with some water blurring and she knows her stuff!!!!
So there is no easy answer, though in your case there is room for some improvement
It is very disheartening when your pictures are lost like that, as so many of mine have.
I have some examples on the home page here, they aren't perfect by any means but with practise they are improving. There are a lot of things to be thinking about in rough water, your balance, usually a moving subject and of course, camera shake.
But I'll keep on clicking away!!!
Good luck!