The dog returns.....

So Alba was very spoiled today and was treated to a morning at the beach.....aperture and action shots was the aim and I got a few that I was happy with.
Someone in the know may be able to help me...I was wanting to get a movement shot of the water ( extended time of the shutter speed being open) however I couldn't get the aperture to play the part and everything was over exposed....does this mean I need a filter? ie sunglasses for my camera??!
TIA!