Water tank fill without overflow

Do you have water tanks without a deck fill access? If you have one like mine, then just inserting a hose to fill results in constant attention to avoid water spilling into my lazarette:

I solved this by making a adapter to connect the hose to the tank 1.5 inch pipe thread:

Now, the tank can be filled until water flows overboard through the vent. With my 3 tank setup, the vents are connected and all three tanks fill prior to water going overboard!

This design includes a rotating connection for the hose and an on/off value to make attaching and starting/stopping the water flow easy.