Deck drains

[Rich L]

How do you guys deal with removing rain water off the deck. My uncle who owned the boat before me placed a small pump with float. That was all good until the float crapped out and got a call from the marina that they had to bail it out. I read a few posts about self bailing decks and I'm not about to leave the valves open on the drains.For now I replaced the float and is working fine.

[Capt. Bob]

CCP correct?

You stated "deck drainage" meaning the area you walk on and can physically see correct or are you talking below deck i.e. the bilge?

Water on the deck will drain to the rear corners and will flow overboard (via displacement).
Water in the bilge is another thing and yes you need a float switch or auto pump to handle that. Unless you have a compromised sealing of the deck or of the deck drain hoses or their corresponding thru hull connections or you left the brass drain plug out :o  you shouldn't be getting enough water in that bilge area to swamp the boat. Water can also enter via the tank coffin cover, hatch openings/deck plates, the fish "coffin box" drain and any and all penetrations (think gunnel rod holders in stern area or raw water/livewell thru hull fittings).

You do not want to plug those corner deck drains when the boat is stored in the water.

If you don't have a CCP, kindly disregard.

[Rich L]

Yes Capt Bob ccp, yes the deck not the bilge. I was told to keep the drain valves closed or water will come in. Sounds like bad info to me.

[Capt. Bob]

The deck drains work on the principle of hydrostatic pressure. That is, as long as the deck elevation is above the water level in which the boat is floating, water at the deck level will move to the lower level (the drain allows the force of gravity to overcome the deck force supporting the water). If you plug those drains and it rains, the water cannot escape and will flood the deck.
There is not a tremendous difference at rest between the two elevations but there is enough for the drain to function. When the water level becomes higher than the deck, then water will enter the drain. That can be caused by excessive weight in the stern area or when launching from a steep ramp.

Bad info, Si