Marine head question

[Legend]

Sailfish Head system question. Yesterday i was checking the holding tank level and the light signaled it was 3/4 full. I planned on emptying the tank when I got offshore. When I checked the tank level off shore it was showing no light which signifies low volume. I noticed that I did not close the thru hull valve the last time I used it. Is is possible that the tank could have drained thorugh the valve when the boat was in motion. I checked the holding tank gauges by filling with water and they worked fine.
Hoping I dont have a leak in tank? Any help appreciated. - Thanks

 

[Sean O'Grady]

Sounds to me like you drained the tank while in motion.
Next time make sure the valve is closed and secured closed with a wire tie.
Big fine if you're stopped for an inspection and the holding tank sea cock is found not to be secured in the closed position.