I down-loaded 7 mods today. This is one of 3 that actually worked, however, it is driving me crazy trying to find a key in the water. It might just as well be a needle in a haystack. The textures make it hard for me to see underwater and it is suposed to be near the dock, but there are 3 docks
can anyone help with this please ?

Open the mod in the CS and see if you can find it? Usually the items that has been changed by the mod has an asterisk behind it, thats generally how I deal with mods that drive me up the wall
Or use the console to open the chest or door.