My bow thruster will not leak to an exit to the bilge. It will be stopped at the forward head where it must be dealt with manually. If you have a situation where seawater has a direct path to the the engine room bilge (other than the anchor locker), I would say that it's not original (or I didn't read your statement correctly). ..
Having a water alarm next to the rudder quadrant is a great idea. I just have to hoist the bed once a month while we're parked, once a day while we are underway.
SM 209, Adagio