Thread: Minimizing Through-Hulls / Seacocks
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Peggie Hall Peggie Hall is offline
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First recorded activity by BoatBanter: May 2007
Posts: 43
Default Minimizing Through-Hulls / Seacocks
wrote:
I'm about to begin the installation of plumbing components on a 30 ft
sailing cutter (new, "holeless" hull) with a basic complement of
fixtures which require through-hulls & seacocks:

Galley Sink Drain
Galley Salt Water Foot Pump
Engine Raw Water Intake
Head Vanity Sink Drain
Head Toilet Raw Water Intake
Head Overboard Discharge pre Holding Tank
Head Overboard Discharge post Holding Tank

My basic questions a

Which - if any - of these fixtures can share a common seacock, and
what are the standard or typical hose sizes for each of these
functions?

Toilet intake and vanity sink drain can share a thru-hull...just be sure
that thru-hull is forward of any toilet or tank discharge thru-hull.

If you plan to spend most of your time offshore beyond the "3 mile
limit," where you can flush the toilet directly overboard, put a y-valve
in the head discharge line that allows a choice of going overboard or
into the tank. But if you'll spend most of your time in coastal waters,
almost all SoCal waters are "no discharge"...in which case, send
everything to the tank.

I would eliminate any y-valve in the tank discharge line by spec'ing TWO
discharge ports in the tank...one directly to the deck pumpout fitting,
the other directly to an overboard discharge pump and thru-hull. You
should be able to tee the tank discharge into toilet direct overboard
thru-hull.

Toilet intake and sink drain lines are both 3/4" ID. Holding tank
discharge is 1.5" ID unless you plan to use a macerator pump...macerator
pumps are 1.5" in, 1" out. Manual pumps and electric diaphragm pumps are
1.5" in and out.

We prob'ly should talk a bit about where to locate the tank, venting it,
where to put fittings, where to put vented loops, toilets etc. in more
detail than is practical in open forum. If you'd like to do that, you
can email me at (myfirstname dot mylastname)at gmail dot com. I'll be
glad to help you.


--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/boat_odors/
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