Long Exposure landscape: Lady Bay Auckland

I often marvel at landscape photos from the National Geographic. The waves and clouds in those photos are all so "Dreamy".  I soon learned about the long exposure with Neutral density filters.  I bought one recently, a Cokin ND2-ND400 variable filter.  These photos were from my first attempt at long exposure with a ND filter.  These were shot at just under the maximum filtering capacity of the filter, i reckon i was doing about -7 or -8 stops. Around 10-13 sec exposures.  Ideally i would like a much longer exposure but for that i will need much darker filter.  Anyway, i am quite happy for what i have got considering this is my very first attempt.