Someone asked on Flickr how you get waterblur in your photographs.
You can go into aperture priority stick and stop down to f/22 to get waterblur, but you are hitting the diffraction limits of the lens and losing sharpness. (Remember, if you have a polarizer hanging around, it doubles as an 2-stop ND filter. If you have a pocket digital camera, your sunglasses can be a filter in a pinch.)

3 exposures (2.5″, 0.6″, 1/6″) (Nikon D70) ƒ22, iso 200, 12mm (18mm), 81A + polarizer, tripod
ND filters and a tripod are your best bet. A neutral-density (ND) filter allows you to experiment with waterblur on a sunny day:

3 exposures (3″, 1.3″, 1/4″) (Nikon D70) ƒ16. iso 200, 12mm (18mm), vari-ND, tripod