water tank installation

Here is something I should know, but don't. And I can almost see a picture someone posted, but can't find it. I have port and starboard water tanks under the main cabin settees, made of plastic . They are kept down with the screwed down settee platforms. Is there part of the IGU that holds them in place athwartships? If not, what holds them in place? And, on the starboard side, if I took off the cheap plywood facing wood just above the cabin sole that forms the front of the seat platform what would I encounter? I know there is a wire race at the bottom of the settee face just inside the plywood facing piece. Thanks.

Morning Terry, both water tanks sit in a full cradle formed by the IGU. The only portion you need to hold down is the cover. Like you I have taken off both side covers to do various work and found a raceway that could handle pipes and wire.This is a picture I took of the port side when I had the plywood off. Starboard side is the same.