Adding thru hole option for toilet line

[Will10MNT]

I've got two heads on my boat. And I'm looking to add a thru hole option to one of them for offshore use. Its a vacuflush system and currently goes straight into a holding tank, but as the line comes from the tank to the pump out area it has a y selector right next to an existing thru hole. I dont imagine its as simple as slapping some hosing from the switch to the thru hole, especially with the switch being located after the holding tank. Do I need a pump in the line to empty from the tank to the thru hole, or will their be any issues with water line where it is currently located?

[Ded reckoner]

We have a manual pump downstream of the y-valve and before the seacock.

[chrisr]

our holding tank sits vertically above the w/l, and has a 'dump' valve (pardon the pun.

when we want to, and are in a suitable location, simply open the dump valve and empty the tank

if on passage off-shore, we just leave the valve open all the time.

works well for us

cheers,

[Spot]

Through hull is a skin fitting on a boat. Through hole is a common electronics term used all day long at my day job...

[peghall]

Everyone else has described dumping the tank...I think you want to be able to flush one of your VF toilets directly overboard INSTEAD of into the tank. Easy to do: the suction only gets the flush TO the vacuum pump, which then pushes it the rest of the way to its destination--tank or overboard.

So all you'd need is a y-valve in the line between the vacuum pump and the tank and enough hose to go from the y-valve to the existing thru-hull and a tee or wye fitting to join it to the overboard discharge line from the tank.

You're welcome to contact me directly if you want to discuss in more detail than is practical in a discussion forum.

--Peggie

[Will10MNT]

Thank you very much peggie, this is a lot of what I was curious about. Ive never had a vacuum based head before so I wasn't sure if they could pump straight from the vacuum chamber to a through hull without an additional pump in that line or not. You've saved me a lot of headache, now only if putting in the new duck bill valves fixes the vacuum issues I might actually have a good functioning head in a week or so.

[Will10MNT]

I'll be getting your book too, between the mildew and bildge problems creating smell, the additional issues with the head systems has increased my interest in boat smell measures as of recent.

[Ded reckoner]

Yeah, I think Peggie nailed it. OTherwise, if the four duck bill valves are the source of your problems, then you should notice this in their "calcified" and distorted bills. The four bolts at the base of the pump assembly should be tightened snugly. But, my understanding is, they don’t need to be over-tightened since system vacuum level is not impacted by how tightly these secure the assembly to the tank assembly. Of course, after replacement, apply at least four turns of Teflon tape to all plastic threads and screw-on fittings. The swivel nut needs to be securely tightened to the transition fitting. The transition fitting needs to be securely tightened to the valve adapter. The two hose clamps need to be securely tightened around the hose.

[Ardbeg]

Is there not also a question of Coast Guard and rules? I thought you could not be able to discharge into the water if not offshore? Or is that simply the Great Lakes? If boarded up here, you could be subject to large fine if they find a thru hull that can work. For me I connected to thru hull when going offshore but when I came back I blocked thru hull again. Can't afford the $10,000 fine they warn about.

[Will10MNT]

To my understanding, im ok as long as im atleast 3 miles offshore for my area to utilize any thru hull options.

[peghall]

Thank you for ordering my book! Its title (my publisher's idea) is a bit misleading...'cuz although it does deal with every source of odor on a boat and how to cure, or better yet PREVENT 'em, it's actually a comprehensive "marine toilets and sanitation systems 101" manual that explains the laws, describes all the types of systems and how they work, and will help you learn how to operate and maintain your system to prevent 99% of problems instead of having to cure 'em. 'Cuz you get to do any preventive maintenance on your terms when it's convenient...the need to cure a problem never happens when it is!

I've written piece I call "VacuFlush 101" that you'll also find useful...it's not in my book. It explains how the VF works (an amazing number of owners think they do, but actually don't) and how much water it really needs to keep it working trouble free. I'll be glad to send it to you--and to anyone else who wants it--if you'll send me a PM that includes your EMAIL address...no way to attach anything to a PM.

--Peggie

[Disailor]

To avoid CG issues there needs to be a lock on the y-valve to absolutely disable the possibility of dumping inside 3 mile.

[peghall]

The OP did say "for offshore use."