I have experienced an unusually volume of water in my bilge after typical race night
>I would empty the bilge pre-race only to find it half full with dark dirty water / and an impression that it comes from the aft hidden bilge (to be confirmed)
>there is no water accumulation between races when at the dock
>there is no water coming when running the engine (in neutral) at the dock....thought it may be a leaking hose
>there is no apparent oil, anti-freeze nor fuel in the water....but it is much dirtier that lake water / with brown sediment

A normal sail night is 10-15 min motor out / one hour race / motor back

Any thoughts where this water may be coming from?
My next step was to go out and strictly motor around with the engine cover off and make observations

Appreciate any theories

Taras