sharing thru-hulls? - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #1  
Old 03-28-2012
Member
 
Join Date: Aug 2011
Posts: 61
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 4
tominny is on a distinguished road
sharing thru-hulls?

I am changing all thru-hulls and seacocks and replacing them with new ones from Groco. In the head, there was a 1 1/4" thru-hull for the head intake and a 1/2" thruhull for the sink drain.
The old 1 1/4" thru-hull flange had an unusual shape on the outside of the hull that was put in flush with the hull. When we took it off, the new thru-hull did not fit in. So we decided to close both holes with fiberglass mat and barrier coat. The 1/2" hole was right next to it and needed to be enlarged to 3/4" anyway (Groco's smallest size).

NOW, I am wondering if it makes sense to drill two holes again, or if the head intake thru-hull can be shared with the sink drain, i.e. only requiring one hole? I was thinking to put a V-valve after the seacock with one end going to the head and the other to the sink. The end with the sink has a stop ball valve that is shut when the sink is not being drained.

Will that work? Any potential trouble down the road? What do people think?
__________________
Thomas

Tartan 34C
New York City
Reply With Quote Share with Facebook
  #2  
Old 03-28-2012
hellosailor's Avatar
Plausible Deniability
 
Join Date: Apr 2006
Posts: 10,629
Thanks: 2
Thanked 89 Times in 87 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about
Re: sharing thru-hulls?

The head could "suck air" from the sink drain if it doesn't see enough volume from the seacock. But that also means you can hold gray water in the sink line, or use fresh water from the sink, to flush the head.

It CAN work, objectively I'd say try it and if it doesn't work out for you, be prepared to install the second seacock.

The other problem may be valving, i.e. if you have to shut the sink drain in order to let the head work without sucking air from it, guests may simply not get the idea. But guests and head valving are a whole other issue, aren't they?
Reply With Quote Share with Facebook
  #3  
Old 03-28-2012
Senior Member
 
Join Date: Sep 2011
Location: Massachusetts
Posts: 132
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 4
mm2187 is on a distinguished road
Re: sharing thru-hulls?

The whole setup sounds a little odd. I am not sure why you would need a 1 1/4 intake to flush the toilet. Most toilets use only 3/4 intake (the inside diameter of the thru hull). A 1" flush mount thru hull has an outside diameter of 1 1/4" and a 3/4" thru hull has an outside diameter of 1". Are you sure that the 1 1/4 is not 1 1/2 which is the waste pipe out (in which case I could keep it separate)
__________________
Schock - New York 36
Portsmouth, RI
Reply With Quote Share with Facebook
  #4  
Old 03-28-2012
Member
 
Join Date: Aug 2011
Posts: 61
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 4
tominny is on a distinguished road
Re: sharing thru-hulls?

Thanks for the responses. The inner diameter of the big thru-hull is definitely 1 1/4. The outer diameter of the Groco thru-hull fits in well and the backing plate has the same hole size, so it is convenient to stay that size (and I already have the 1 1/4 thruhull and seacock.
On my head set-up, the intake and discharge go through the same 1 1/4 hole, btw. Would it be a bad idea to connect the sink drain to this hole as well?
__________________
Thomas

Tartan 34C
New York City
Reply With Quote Share with Facebook
  #5  
Old 03-28-2012
Senior Member
 
Join Date: Sep 2011
Location: Massachusetts
Posts: 132
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 4
mm2187 is on a distinguished road
Re: sharing thru-hulls?

On my head setup i have a 3/4" intake to flush with. goes through the pump and comes out in a 1 1/2" tubing. The sink in my head shares the same seacock as the sink in the galley.

I would not connect the drain to the sink with the head just in case you get some sort of a clog and gets pushed into your sink, also it could pull air from the sink when trying to pull water through the thru hull.
__________________
Schock - New York 36
Portsmouth, RI
Reply With Quote Share with Facebook
  #6  
Old 03-28-2012
RobGallagher's Avatar
HANUMAN
 
Join Date: Aug 2001
Location: Noank, Connecticut, USA
Posts: 1,329
Thanks: 7
Thanked 15 Times in 14 Posts
Rep Power: 14
RobGallagher is on a distinguished road
Re: sharing thru-hulls?

A couple of quick thoughts to consider:

Consider using fresh water to flush the head.

Don't even plumb the water intake to the head, simply use the hand held shower nozzle to fill then flush the bowl as you pump. Leave the head leaver in the "flush" position.

Much of the odor from a salt water flushed toilet may actually be the low tide smell from dead marine organisms in the bowl and plumbing.

Good luck.
Reply With Quote Share with Facebook
  #7  
Old 03-28-2012
Faster's Avatar
Just another Moderator
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 14,704
Thanks: 69
Thanked 197 Times in 189 Posts
Rep Power: 10
Faster has a spectacular aura about Faster has a spectacular aura about Faster has a spectacular aura about
Re: sharing thru-hulls?

Quote:
Originally Posted by RobGallagher View Post
A couple of quick thoughts to consider:

Consider using fresh water to flush the head.

Don't even plumb the water intake to the head, simply use the hand held shower nozzle to fill then flush the bowl as you pump. Leave the head leaver in the "flush" position.

Much of the odor from a salt water flushed toilet may actually be the low tide smell from dead marine organisms in the bowl and plumbing.

Good luck.
I suspect you're right about the odour issues vs fresh water.. but I wonder how many will want to give up fresh water reserves for flushing? Plenty of boats have close to inadequate water storage as it is.
__________________
Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
Reply With Quote Share with Facebook
  #8  
Old 03-28-2012
RobGallagher's Avatar
HANUMAN
 
Join Date: Aug 2001
Location: Noank, Connecticut, USA
Posts: 1,329
Thanks: 7
Thanked 15 Times in 14 Posts
Rep Power: 14
RobGallagher is on a distinguished road
Re: sharing thru-hulls?

Quote:
Originally Posted by Faster View Post
I suspect you're right about the odour issues vs fresh water.. but I wonder how many will want to give up fresh water reserves for flushing? Plenty of boats have close to inadequate water storage as it is.
I guess it all boils down to how much access one has to filling up their tanks.

I'm on a mooring but have access to a dock with a hose.

When I take my vacation cruises it's ironic that I'd rather wash dishes in salt water and flush my toilet with fresh. You couldn't pay me to drink that stuff in my old tanks
Reply With Quote Share with Facebook
  #9  
Old 03-28-2012
Faster's Avatar
Just another Moderator
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 14,704
Thanks: 69
Thanked 197 Times in 189 Posts
Rep Power: 10
Faster has a spectacular aura about Faster has a spectacular aura about Faster has a spectacular aura about
Re: sharing thru-hulls?

Quote:
Originally Posted by RobGallagher View Post
I guess it all boils down to how much access one has to filling up their tanks.

I'm on a mooring but have access to a dock with a hose.

When I take my vacation cruises it's ironic that I'd rather wash dishes in salt water and flush my toilet with fresh. You couldn't pay me to drink that stuff in my old tanks
True.. in other areas access to fresh water can be far and few between. btw we have installed a Brita faucet filter in our galley.. so we only filter drinking water selectively.. it's amazingly effective. In our northern areas here you could end up many days between water fills (unless we get one of those rare rainy days )
__________________
Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
Reply With Quote Share with Facebook
  #10  
Old 03-28-2012
RobGallagher's Avatar
HANUMAN
 
Join Date: Aug 2001
Location: Noank, Connecticut, USA
Posts: 1,329
Thanks: 7
Thanked 15 Times in 14 Posts
Rep Power: 14
RobGallagher is on a distinguished road
Re: sharing thru-hulls?

Quote:
Originally Posted by Faster View Post
True.. in other areas access to fresh water can be far and few between. btw we have installed a Brita faucet filter in our galley.. so we only filter drinking water selectively.. it's amazingly effective. In our northern areas here you could end up many days between water fills (unless we get one of those rare rainy days )
You probably did your research, and I don't mean to sound like a know-it-all... as I have no idea where you get your water or the condition of you tanks and lines...

...Just be careful when assuming what and what NOT that Brita faucet filter is actually filtering as not all filters where created equal.

Regards, Rob
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sharing a boat ekhar Boat Review and Purchase Forum 42 05-16-2011 05:06 PM
Sharing the Stoke DBboat General Discussion (sailing related) 8 10-22-2008 12:39 PM
Sharing a crewed charter exwindjammer Chartering 13 09-29-2008 11:23 AM
Sharing the Waters Bruce Caldwell Learning to Sail Articles 0 05-23-2002 08:00 PM


All times are GMT -4. The time now is 08:38 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.