In the middle of the ocean the sedimentation rate is as slow as 0.5 - 1 cm because the sediments are only from the wind, that was blown. then in continental margins, sedimentation rate is very fast at about 2-4 m per 1000 yr. so in deep ocean, sedimentation rate is about 2 - 5 cm per 1000 years.
My guesses are either Portugal or Spain, but I think the country that does provide the best harbor is Portugal
