Thru hull bait tank drain question - yes another one!

Modot66

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Jul 17, 2017
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San Diego
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Matt
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Triton
i have searched and read tons of posts regarding bait tank installs, but had a specific question regarding drain capacity that i haven't seen answered anywhere.

i am installing a 30(ish) gallon bluewater deck-mounted bait tank to my 22' triton center console and had a question on the drain plumbing. the 1-1/2" bait tank drain line will have to exit below the water line as there just is no way to have it exit above. i currently have two existing 1-1/2" thru-hull drains plumbed into the transom, both are below waterline and are connected to the deck drains. both of these already have proper seacocks on them. they sit about 4" below waterline.

my plan was to plumb the bait tank drain into one of the existing thru-hull drains using a y-connector, thinking this would avoid another below the waterline hole.

my question is this: do i need to worry about overcapacity in the drain if i have both the bait tank and the deck drain plumbed together? my deck is normally dry unless i hose it down. so i would think the existing hose can handle both duties. however this is new territory for me so not sure.

thoughts?
 
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Fishbones

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Nov 7, 2005
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Chula Vista
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Rich
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One Off 28' Custom Built Skipjack (SOUTHWESTERN) & 18' Sylvan (Short Runs)
Why not tie the deck drains together and have a separate bait tank drain
 
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Dragon

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May 24, 2006
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Paul
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22' Pro Sport CC / 20' Skipjack Open
Same Thing...I would leave the drains separate and add another 1-1/2' hole below the waterline. All my through hulls are below the waterline. Deck drains, box drains, and bait tank. They drain fine...

Trans. Drains.jpg
 
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downtime

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Sep 12, 2006
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Ronson
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26 Skipjack "Reel Hard"
Saw this done and it didn’t work. The water from the tank ended up on the deck of the boat.
 
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MYNomad

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Dec 12, 2007
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Yes
I suspect that your existing through hulls could easily handle the flow of your bait tank but you need to tie it together properly so that the straightest path for the water to follow is straight through the through hulls, or some of that water may back up onto the deck. Basically, you need "Y" fittings, not sideways "T" fittings.

But it would be a really bad idea to use those existing through hulls since you will be diminishing the capacity available to drain your deck (at least while your bait tank is running). That is a safety issue. Even though your deck is normally dry, if you were to take a big wave over the transom (etc.), you want that water to drain out asap -- the longer your deck is swamped the more at risk to a second wave you will be, and the more water . And even two 1-1/2" through hulls won't drain all that fast, you should not be diminishing their capacity. Much better to install a new through hull.
 
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Modot66

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Jul 17, 2017
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San Diego
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Matt
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Triton
thanks for the feedback everyone, all good points, especially the one about reducing the self-bailing deck capacity. just ordered another seacock and will add another thru-hull just for the bait tank drain.

thanks again!
 
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