Need Help on Pump out Design

T

thompsdw

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So I have a boat on a rual lake. I do not have access to any waste pump out stations. When I have tried to get someone to pump out - its a disaster because they don't normally do that. Oh, wait - here is the final nail - my head only had a 5 gallon holding tank.

Yep, a PITA. So here is what I have resolved myself to ..... I installed PVC pipe and fittings that go below deck and back above deck to a macerator pump. I basically use that pump to pump out the small tank into a 5 gallon bucket and then dispose of that at a marine porta-pot. Yuck - but you gotta do what you gotta do.

So here is the problem I need help on. The macerator is self priming but only when liquid is present. The fact that the plumbing goes below deck and comes back above pretty much ensures that the pump is only exposed to air when I hit the pump button. So I am having to prime with water every time to get the pump to prime.

The steam is mostly water with limited solids. I have thought about installing valves to hold the liquid head to improve priming. Is there a different pump or solution that I should be thinking about?? Be nice to just pump and be done - this is yucky enough to start without having to prime. Any help is appreciated.
 
Just instal the macerator next to the tank so it will prime right away
Avoid PVC as it can crack unless thicker walled. I d use sanitation hose to a pump out fitting on deck. When ready to pump screw in a hose adapter with cam locks and attach a short hose from that to your bucket (hopefully a covered bucket)

Be careful with crappy jabsco style macerator they can't run dry. The sea land bellow pump is more $ but more reliable
 
You might want to think about this again. The ability to pump raw stuff overboard is frowned upon (as in a hefty fine) without some way to prevent it from happening. Most require a positive lockout to avoid fines from officials.

Bob
 
I am aware of that, but I really have no choice. I am using an enclosed bucket and there is no spillage. I just would like to have as "clean" a transfer as possible. Is the SeaLand more likely to prime with some air present?
 
quote:
Originally posted by PascalG

Be careful with crappy jabsco style macerator they can't run dry.

Click to expand...


???

One of our original Jabsco 18950 macerators lasted for 14 years (needs a new impeller), and the other for about 11 years (finally locked, likely from lack of use).

The first I mentioned was on the fishbox, so always had to prime itself, no issues...

Not a recommendation, just an observation.

-Chris
 
http://www.walmart.com/ip/Global-Passport-4.8-Gallon-18-Liter-Portable-Toilet/12321234?action=product_interest&action_type=title&item_id=12321234&placement_id=irs-106-t1&strategy=PWVUB&visitor_id&category=&client_guid=3021d9c3-54a6-47bf-8368-28ce369cb039&customer_id_enc&config_id=106&parent_item_id=22084113&parent_anchor_item_id=22084113&guid=6c2426fa-435d-4a1a-a529-3e4b6462ac2c&bucket_id=irsbucketdefault&beacon_version=1.0.1&findingMethod=p13n get one of these
 
quote:
Originally posted by Salvatore356

http://www.walmart.com/ip/Global-Pa...fault&beacon_version=1.0.1&findingMethod=p13n get one of these

Click to expand...


The KISS principle. If you can carry 5 gals. out in a bucket, you can carry it out in this, and cut out all the pumps and plumbing you need to transfer it from one container to another. The Dometic 'Sealand' 976 has the same features/capacity for about the same price.

(my 24' Chris Craft had the same design as the Op's, but mine only held 2.5 gals! Some moron at CC decided it was a good idea to hard-plumb a porta-potti and call it an MSD, so it required a pump-out station to empty)

My .02
 
Maybe another tack - if the existing 5 gallon waste holding tank is OEM, then it should be a Type III Marine Sanitation Device (type III MSD) and has a dewatering connection - which is basically a long pipe into the tank so a vacuum system connected to the pipe would suck the muck out of the tank. . ..

You mentioned that when someone tried to pump it out it was a disaster. Why? Did that person not have the proper connection?? if that was the problem, you may be better off buying the proper fittings to adapt the MDS's discharge port to the contractor's system.

If that's an option, it's certainly cheaper - and safer - than adding pumps, piping, wiring switches, valves . . . you get the idea.
 
How about using a whale gulper diaphragm pump. Reliable, self priming and no winterizing,
 
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