Whale Gusher Pump Question

harbin2 · #1 (**permalink**) 10-26-2008

The simple question is: Is the Gusher 8, Mk 111 manual pump designed so you can suck water through it from it’s discharge but not allow water to flow in the opposite direction?

I recently purchased an Islander 30 that has had a Y valve added to the original waste tank design. The Y valve lines up the head to pump either to the holding tank or to the overboard seacock (which is closed). When I go to my local pump out, the pump out seems to work fine but when I try to add fresh water to the waste tank deck fitting (to flush out the waste tank), the water backs up. The Whale gusher pump is acting like a check valve. Is that how it is designed? It kind of makes sense because when you hand pump, it draws from the waste tank and discharges to the outlet of the pump. If this is the case, then it appears the only way to get fresh water into the holding tank is to pump it through the head. Make sense?

Thanks, Ron

sailingdog · #2 (**permalink**) 10-26-2008

Harbin-

Almost all diaphragm pumps work as pass through pumps, because they use a joker or check valve at the outlet. If there is any vacuum on the outlet side, the water will push through. However, water can't flow back through the pump... so yes, a diaphragm pump will act as a check valve... because that is effectively how it works... it is two check valves with a bellows between them. Open the bellows, the outlet hose valve closes and water fills it...compress the bellows, the inlet side closes and the water rushes out the outlet valve...

What they should have done is put the Whale Gusher in the line going to the seacock and through-hull discharge, not in the common line coming up from the holding tank pumpout fitting. That way, if you have the y-valve pointed to the deck fill, you can pour water in via the deck fill.

I would highly recommend that you make this change ASAP... It will make your life easier and it will put less wear and tear on the pump itself.

So the setup should end up like this

Tank pump out fitting ====> y-diverter =====> to deck pumpout fitting
...............................................val ve =====> Whale Gusher Pump ====> seacock/through-hull.

harbin2 · #3 (**permalink**) 10-26-2008

Thanks a bunch. I made a sketch that I'll scan and post here. I think the current set up is probably OK - I'm just not doing a good job of describing it. If you are correct, this can be a "fun" winter project.

One other question. The last time I pumped out the holding tank, I heard a fairly loud noise from inside the boat - like something being sucked dry. Now that I understand the current configuration, I'm sure it was air being sucked into the toilet (via the gusher, the holding tank, and the Y valve). I'm wondering if I should be setting the Y valve to mid position (closed in both directions) so I'm not sucking air through the head. I wouldn't want to ruin any of the plumbing in it. One note - when I first realized I had a "problem" (being unable to fill the holding tank from the deck thru hull), the guy at the marina suggested my vent was clogged. I had to remove it from the hull to clean it out - it was very clogged. But, now that it's unclogged, I'm still not sure it could pass enough air to keep from collapsing the holding tank if I had the Y valve closed. Your thoughts are appreciated.
Ron

sailingdog · #4 (**permalink**) 10-26-2008

After re-reading your opening post... which head do you have? Sounds like a Lavac. Correct me if I'm wrong but the head connects to the WHALE GUSHER, which then goes to a diverter valve—which either goes to the head or the seacock, yes? The holding tank only discharges to the deck fitting, right?

In that case, the Whale is on the wrong side of the holding tank to be acting as a check valve for pouring water into the tank via the deck fitting. There shouldn't be anything preventing you from pouring water into the head via the deck fitting. A clogged vent would cause that as a symptom, since you have to let air out to let the water in...and the air can't go out the holding tank inlet hose... it has to leave via the vent line.

One thing I would highly recommend is changing the setup on your head and holding tank setup, since right now, if your holding tank is full and you're in an area without pumpout facilities, you can't dump the tank.

The way I generally recommend a head be plumbed is to have the head always discharge into the holding tank. Then you have a diverter valve in the holding tank pumpout line. One side of the diverter valve goes up to the pumpout fitting on deck, the other goes to the seacock and through-hull. This gives you the capability of emptying the holding tank when you're sailing out past the three-mile limit, and can save you some hassles when returning from a longer trip....since you can dump the tank and not have to find a pumpout station.

harbin2 · #5 (**permalink**) 10-26-2008

Again, thanks. I believe you are correct that it is plumbed incorrectly. I'm leaving town early in the morning but when I get to my destination, I'll try and scan my sketch so you can see exactly what I have. It sounds like I will be doing a modification though. I'll be back in 48 hours.
Ron

sailingdog · #6 (**permalink**) 10-26-2008

Good enough...

Look forward to seeing the sketch.

harbin2 · #7 (**permalink**) 10-28-2008

[IMG]C:\Documents and Settings\Ron\Desktop\waste1.jpg[/IMG]

harbin2 · #8 (**permalink**) 10-28-2008

Above is my first attempt at posting an image on this fantastic site. Wasn't sure just how (or if) it was going to work.
Anyway, it shows the original and current design where a previous owner added a Y valve. My question is, is the current design a good one (what is the purpose of the Y valve?
Thanks, Ron

sailingdog · #9 (**permalink**) 10-28-2008

Harbin-

Neither of those designs make sense. I'll post a drawing of how it should be setup.

sailingdog · #10 (**permalink**) 10-28-2008

Here's the drawing:

This setup minimizes the plumbing and maximizes the capabilities of the head system. The head always discharges into the holding tank, but the holding tank can be emptied via the through-hull and whale gusher pump when you're out past the three-mile limit, or via the hull deck fitting and a pumpout boat/dock.

It also allows you to fill the holding tank with water to rinse it via the deck pumpout fitting. It also doesn't put any excessive wear on the diaphragm, which would be the case in your two drawings since the pumpout deck fitting requires any pumped out waste to pass through the pump. This setup doesn't require the pumpout system to pull the waste through the pump.