Water inside the board

[valentine]

I have always sailed with closed vent. When I check the wait of my slalom board it was7.7 dry. The balance mows to the nose.No visible damage. I tried to leve the board on the sun for 5 ours with opened vent and up side down position,but no water, even the vent hole is dry. Could anyone give my an advise ,how to get rid the water ,and find the damage? I like my board, and want to fix it. Sorry my English .Waitihg for help.