This is a re-post of what I did years back, I watched in awe seeing both my bilge pumps running like crazy during a heavy 1K rain storm. I had both a 1500gph and a 2500gph pumps both running like like crazy, they are both wired to independent batteries. It lead me to install hatch drains, I realized near 1/2 the rain ended up going into my bilge. The hatch it's self is about 25% of the deck area then add the run off from the cover, add the two together over half the rain is directed into our bilges. That lead to me installing deck drains! With many rack boats it is hard to reach the plug and many forget on the trailer, I know that I do at times but now have very little staying in the bilge.