Improving macerator installation

Dan_Y

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Oct 13, 2008
514
Hunter 36 Hampton
holding tank.jpg

After reading several macerator premature failure threads it seems that many macerator are installed where they stay filled with holding tank waste in between use and the pressure of the tank water against the seals constantly. The factory installation in our boat has the macerator level with the bottom of the holding tank and below the waterline with instructions to open the seacock and start the macerator pump and turn off the macerator as soon as the tank is empty then close the seacock. So in between uses the macerator has seawater in the discharge line and black water in the intake side...a tough life, especially if infrequently used. More frequent use and maintenance may be part of the answer, bit a better installation to help the pump succeed seems to be needed.

We've owned our 2008 h36 for two months and the macerator is shot. Motor won't run (open circuit) and very hard to turn using the motor end shaft slot that made for a screwdriver. It did not show signs of leaking. Note this is a Jabsco self priming macerator 18590-2592.

Based on my interpretation of Peggy's and others comments, I'm proposing to install the new macerator above the waterline to keep salt water out of the discharge and place a loop on the input to keep black water out of the pump in between uses. Comments or improvements appreciated.
Dan
 
Mar 20, 2004
1,729
Hunter 356 and 216 Portland, ME
we did much the same thing on Escape after the jabsco failed - a leak - and it's a great idea. The Jabsco can handle a 4' head, so raising the pump isn't an issue. I also added a Y valve before the pump with a capped line mounted up the side of the tank with a hose fitting. This lets you connect the tank output to the pump or turn the valve and close off the tank and connect the pump to a flush line with clean fresh water (while you are in a discharge zone) to clean the pump. It's worked fine for us for 5 years now. An additional benefit, since we sail in a no discharge zone - the CG requires that the discharge output be locked closed, and there's no easy way to do that with the standard Hunter thru hulls. The Y valves are designed for that and have lock tabs you can tie wrap to meet the requirement.
 
Dec 2, 1997
8,709
- - LIttle Rock
Why not put the macerator pump where you show the top of the loop (you can get away without the loop if the macerator pump is above the tank) and run a straight sloping line to the thru-hull....eliminating the 90 in it.

Waste will always rise in the discharge hose to the level in the tank...so I'd use hard PVC from the tank discharge fitting to the top of the tank...switch to hose to connect to the macetor.

And btw...I don't see any pumpout line coming out of your tank.
 

Rick D

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Jun 14, 2008
7,132
Hunter Legend 40.5 Shoreline Marina Long Beach CA
When I had my 40.5 recommissioned seventeen years ago, the shop modified the macerator install by going up from the tank higher than the tank (maybe 8-12 inches) and then downhill to the through hull. Never had an issue with standing waste or seawater, and I have repaired or replaced the macerator about a half dozen times. It gets frequent use on our boat. Good luck on your mod.
 
Feb 10, 2004
3,919
Hunter 40.5 Warwick, RI
When I had my 40.5 recommissioned seventeen years ago, the shop modified the macerator install by going up from the tank higher than the tank (maybe 8-12 inches) and then downhill to the through hull. Never had an issue with standing waste or seawater, and I have repaired or replaced the macerator about a half dozen times. It gets frequent use on our boat. Good luck on your mod.
Ditto what Rick D said.
 
Jan 25, 2011
2,391
S2 11.0A Anacortes, WA
I hear about so many macerator failures..why not a manual pump? I havent figured out where to mount mine yet but short term, it will be used on deck when needed. For me, usage would be rare anyway as British Columbia doesnt really care about the issue which is where we cruise most of the time.
 

Dan_Y

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Oct 13, 2008
514
Hunter 36 Hampton
Peggy (and Rick D)....Ohhhhhhhhhhh That's an even better idea to locate the macerator above the tank and eliminate the loop. Hard PVC from the tank outlet to the macerator makes sense as does eliminating the elbows from the discharge side to the seacock. Access to the macerator is a bit more difficult up there but the benefit is worth the trouble.

I do have a pump out and vent, I just got lazy in my drawing. I probably need a larger vent opening because Hunter used a fuel vent fitting to vent the holding tank through the hull. I either read about needing a large vent for air exchange in the tank in your book or in this forum. Makes sense. Unfortunately, I have to remove the inside of the LPG locker to get at both the pumpuot vent fittings or to change those hoses.

Per Mark's comment...Our '91 h30 had a whale gusher manual pump instead of the macerator in essentially the same configuration. That is a tempting idea, but I think about when I sell the boat (to upgrade of course) and want to keep the "modern" conveniences intact.

When I removed the macerator today, its inlet was filled with tank sediment. It appears I have more tank cleaning to do because I can see sediment lines at several levels (white poly tank material) in the tank where it must have sat partially filled for long periods. There is an access port in the tank top for that purpose I imagine. Fortunately our new slip is on the dock with the pump out station and fresh water hose and we can stop at the pump out station on our way back to the slip.

Again, thanks for the ideas and comments.
 
Dec 2, 1997
8,709
- - LIttle Rock
It appears I have more tank cleaning to do because I can see sediment lines at several levels (white poly tank material) in the tank where it must have sat partially filled for long periods. There is an access port in the tank top for that purpose I imagine.

There's a MUCH easier way: pump out the tank, then put enough water into it via the deck pumpout fitting ('cuz that sends the water into the tank at the bottom to stir up any sludge) to cover the bottom to a depth of at least 4"...pump that out. Repeat...repeat...till you're pumping out clean water. Last step: put the same amount of water in the tank and turn on the macerator pump to rinse it out (Since no one will believe that you're only discharging clean water, best to kist add the water while at the dock and wait till you're away from it to turn on the macerator pump).

This should be done at least 2-3 x season and especially in preparation for winter or other extended layup.

If there's a buildup of animals fats on the tank walls, fill the tank with clean water and add a couple of gallons of liquid detergent...engine degreaser works great for this. Put about 10 lbs of ice in the tank--use icemaker ice...it's bigger and harder than bagged ice...go sailing and tack a lot. Let the solution remain in the tank for up to 24 hours if possible...then pump out and thoroughly rinse the tank.
 

Dan_Y

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Oct 13, 2008
514
Hunter 36 Hampton
Your way appeals to me much more than what I was considering when using the tank access port! Degreaser, ice, and sailing - an unlikely but useful combination! Thanks Peggy!
 
Jan 25, 2011
2,391
S2 11.0A Anacortes, WA
I think i would still use the manual pump especially if it was there in the beginning. When u sell the boat, then put the macerator in. Where I want to cruise in northern parts of BC, i can just picture myself not being able to empty my tank because of a macerator issue and no pumpouts available. Even though BC doesnt seem to care, there are areas where i dont want to directly discharge overboard.....and it would save battery power.
 

Meeka

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Oct 10, 2015
5
Hunter 36 Queensland
image.jpeg
Check your skin fitting from holding tank discharge. This is what we recently (and concerning)found on our 2009 Hunter 36.
 

Dan_Y

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Oct 13, 2008
514
Hunter 36 Hampton
Meeka - How could that happen??? Is that fitting as cheap as I think it is? OMG. You were able to pull that off from the outside- did the hose clamps pull thru the hull or did you have to loosen them from inside. If the latter, how did you do it???
 
May 16, 2007
1,509
Boatless ! 26 Ottawa, Ontario
View attachment 115586 Check your skin fitting from holding tank discharge. This is what we recently (and concerning)found on our 2009 Hunter 36.
Meeka, I'm not sure what I'm looking at from your explanation. I think it is the through-hull fitting for the macerator discharge ? If so could that be an electrolysis issue ?

Our boat is a 2003. It had the original Jabsco macerator pump in it until last year. The boat has only been in salt water about 5 years. It started to get noisy so I changed it out. It was very hard to get at. I replaced all the hoses and added a shut off valve between the pump and the tank. It can be accessed from the panel in the aft berth. The hose was then extended so the pump could be mounted in the port swim platform locker on the brace for the rudder post. That way if the pump fails with a full tank it can be isolated and replaced without the tank draining into the bilge.

We have not had any sludge build up. We try to keep it well flushed out especially before a lay up.

Bob
 

Meeka

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Oct 10, 2015
5
Hunter 36 Queensland
We have only recently acquired our H36. We are not as young, slim and as agile as we once were, but even then, getting access to carry out repairs to holding tank discharge system is very difficult, if not impossible, to some things. We managed to tip the boat over enough (in the marina) to change this thru hull fitting in the water. The rest of the skin fittings will be changed when next we haul out. It will be interesting (and dangerous) if they are in a similar state.
The hose from maserator to thru hull fitting and valve was rather clogged, but too difficult to change. I am dreading maserator failure. I know the maserator is allowing waste through if the valve is open. I know our Y valve is bypassing, but have put that in the 'too hard' basket in the mean time, because I'd like to replace all the hoses when we replace it.
I hope the holding tank NEVER needs replacing. The gas locker above it seems unable to be removed without damage.

image.jpeg
 
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Dan_Y

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Oct 13, 2008
514
Hunter 36 Hampton
Meeka
I think I understand now this is the thru hull for the 1" macerator discharge line. Did you notice any leaks inside the port transom locker where this macerator discharge seacock is located? I agree with everything you say about access. I just finished replacing all hoses with trident 102 hose and have the bruises to prove it.:cuss:

All of the seacocks (ball valves) on our h36 are mismatched to the thru hulls (macerator discharge, AC inlet and outlet, sink drains and engine cooling water). The thru hulls have straight threads (maybe ground down a few mm at the end) and the sea cocks have tapered threads. This isn't the cause of the corrosion, but something to consider if you haven't. See the article at Mainsail's www.marinehowto.com titled "Seacock and thru-hull primer / pre information. I will be replacing the seacocks next year. But I'll sure give the macerator seacock/thru hull a closer look this weekend. Thanks!
 

Dan_Y

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Oct 13, 2008
514
Hunter 36 Hampton
holding tank.jpg
I found the room to mount the macerator vertically above the tank. This may preserve the motor if the shaft seal leaks and should keep the impeller chamber and cutter blades drained. I can make PVC pipe work for the macerator intake with a stainless steel sleeved rubber coupling between the tank barbed outlet and a barbed outlet on the PVC pipe. I'm hoping it will not permeate, but would be easy to replace. The barbed outlet at the bottom of the tank appears cemented in (not pipe dope like every other fitting) and I'm fearful of doing damage if I tried to replace it with a threaded fitting to the PVC pipe. Sanitation hose is used on the barbed intake to the macerator instead of the threaded fitting to make removal for rebuilding easier.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
View attachment 115634 I found the room to mount the macerator vertically above the tank. This may preserve the motor if the shaft seal leaks and should keep the impeller chamber and cutter blades drained. I can make PVC pipe work for the macerator intake with a stainless steel sleeved rubber coupling between the tank barbed outlet and a barbed outlet on the PVC pipe. I'm hoping it will not permeate, but would be easy to replace. The barbed outlet at the bottom of the tank appears cemented in (not pipe dope like every other fitting) and I'm fearful of doing damage if I tried to replace it with a threaded fitting to the PVC pipe. Sanitation hose is used on the barbed intake to the macerator instead of the threaded fitting to make removal for rebuilding easier.

Dan,

I have been installing macerators this way for a very long time and found that it leads to significantly longer life. This one is well in excess of 10 years now and is still going strong...


If you keep the pump head just above the tank it is not continually bathed in uric acid etc... I have seen this type of macerator corrode and fail in 1 year when installed at the bottom of the tank. This happened on our 2005 Catalina 310 where it was physically threaded into the tank by Catalina Yachts. One of the SS head bolts physically corroded away and the pump began leaking it was replaced just before we sold the boat in late 2006... Our CS-36 also has the macerator above the tank and it has been in service since 2007 and is in perfect working order.... Across the many hundreds of boats I set foot on/work on I have seen a direct correlation between macerator pump location and longevity unfortunately re-location is not always an easy option.....
 

Dan_Y

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Oct 13, 2008
514
Hunter 36 Hampton
Thanks for validating my suspicion with data Mainsail! Also, the PVC valve on the bottom looks like a great way to keep black water from sitting in the trident 101 between pumpouts and eventually permeating the hose. That makes the install easier using flexible trident 101 throughout.
 
Dec 29, 2017
1
Catalac 9m Tampa Bay
holding tank2.jpg
This is a great thread and makes a lot of sense. I have a question about placement and since my setup is very similar and this thread has great info, I thought I would get everyone's two cents. I have a manual pump inside a cabinet and it works well, but my wife wanted something simple, like a switch to drain the tank when we are 60 miles out fishing for a week. I need to decide on where to put my whale gulper diaphragm toilet pump or, at greater expense add another thru hull.


I have the choice to cleanly mount the motor 16" up and 3 ft horizontally sloped away from the toilet or in plain view next to the toilet, but right where I store some stuff behind the toilet. There it would pull up 6" and push up to the 16" level and then horizontally/slope 1/4" per ft for 4' and then down to the sea cock. Will my second clean install work or kill the diaphragm motor prematurely. My hand pump in this location and has no issues. so I will probably have a Y to use either one.


I have a gift certificate to jamestown so I thought I would get the whale gulper toilet pump. I guess I could build a protective starboard box around the pump if it's located next to the toilet, anything above the pump before the horizontal run would be waiting for me to perform maintenance and be a mess, but in the second option waste wouldn't pile up above the toilet as much. I can't run the hose down unless I want people walking on it and under the floor is blocked in this location. I can't mount the pump above 20 inches due to a thin cabinet in the way.
 
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