Head wiring

[sogood]

I'm giving my Wellcraft 250 a bit of a refurb and as part of that, I'm altering the set up on the head/toilet. I've removed the waste holding tank as it's something that I'd never use, being always at sea. I intend to run the waste directly out, via the existing sea ****. At present, the set up has a Par (read Jabsco) flush pump on the toilet pan, which draws the water directly from the outside.


​I then have a Jabsco macerator on the outlet. My plan, now that the holding tank is gone, is to plumb the waste directly from the pan straight to the macerator and out. Can I then wire the "flush" pump and macerator to the same switch, so that both of them operate at the same time, completing the action in one go?

At present there are two switches, one for flush and one for macerator, with the feed looped from one to the other.

I may well be replacing both pumps as they are badly corroded and jammed up, and so want to know the best way to go about this before I just replace like with like.

Thanks in advance.

 

[CV16]

Wow, where I'm from if they catch you taking a leak off the side of the boat you get a hefty fine. I can't even think of what the fine would be for rigging the head like that around me.

 

[Scott Danforth]

want to know the best way to go about this before I just replace like with like.

Thanks in advance.

start reading on marine law on discharging waste

 

[GA_Boater]

So your boat never comes to port for fuel or maintenance? I hope the CG never boards for an inspection.

 

[garbageguy]

My 1998 Wellcraft 240 SE has a holding tank and a macerator - maybe similar to yours? A random CG inspection here in NY, on the Niagara River all went well - in part because the macerator discharge line had a closed, locked, valve on it. Otherwise, it might not have gone so well. Pumping out the tank isn't difficult, and I don't have to worry about random inspections

 

[mjf55]

sogood, where do you boat and keep your boat? We can guve you much better advice ( or warnings ) based on your location.

 

[Grandad]

Assuming that you're going a-head with this, certainly 2 electrical components can be operated from one switch. There are a couple of considerations though. If the current rating of the 2 motors is substantially different, each may require different size overcurrent or overload protection. Even if they have the same characteristics be aware that simply doubling the wire size and fuse/breaker protection to feed them from a single pole switch may not protect each individual motor effectively. Someone will probably chime in at this point and say that fuses only protect the wires, not the devices, but that's always assuming that the wire was sized closely to the load. Anyway, each can still be on its own protective circuit by using a double pole switch, keeping the 2 circuits isolated from each other. Another way is to use a double pole relay or even a single pole relay controlling a large load as a slave if the relay is controlled by the feed to the small load. That said, I personally wouldn't do away with the tank, if only to have it available dockside. - Grandad

 

[Scott Danforth]

Since its INTERNATIONAL law, I wouldn't want to get caught

 

[GA_Boater]

Should the OP go for a swim right after discharging?

 

[sogood]

Many thanks for all the responses, including the one actual answer, lol! I can understand your surprise, but here in Ireland, the law seems to differ quite substantially to that in the U.S. I did look up the relevant legislation, from the Department of the Marine, which is the relevant Government department and without quoting verbatim, a load of facts and figures, essentially, pleasure/recreational craft authorised to carry 12 people or less, do not come under the regulations that apply to the discharge of waste/sewage, at sea.
It does however suggest that " best practice would include reduction of gross solids eg. by means of maceration of solids, prior to discharge." That's a direct quote from the legislation/regulation. Additionally, any such discharge should take place no less than three miles from the nearest coastline.
​So, now that everybody's mind is put to rest................any further thoughts or suggestions regarding the practicalities of my plan?

Thanks again.

 

[sogood]

Assuming that you're going a-head with this, certainly 2 electrical components can be operated from one switch. There are a couple of considerations though. If the current rating of the 2 motors is substantially different, each may require different size overcurrent or overload protection. Even if they have the same characteristics be aware that simply doubling the wire size and fuse/breaker protection to feed them from a single pole switch may not protect each individual motor effectively. Someone will probably chime in at this point and say that fuses only protect the wires, not the devices, but that's always assuming that the wire was sized closely to the load. Anyway, each can still be on its own protective circuit by using a double pole switch, keeping the 2 circuits isolated from each other. Another way is to use a double pole relay or even a single pole relay controlling a large load as a slave if the relay is controlled by the feed to the small load. That said, I personally wouldn't do away with the tank, if only to have it available dockside. - Grandad

Thanks for that. Food for thought.

 

[mjf55]

sogood, what is the power requirement for the macerator and the flush pump. If significant, I would opt for grandads double pole relay solution.
Another question is can you macerate and flush in a single operation ( time wise, not knowing how long it takes to macerate a load )

 

[sogood]

Hi mj and thanks for the input. According to the specs on the pumps, the flush pump draws 16amps, with a 25amp fuse for protection and the macerator draws 15amps with a 20 amp fuse. Not a million miles apart. So, this begs the question as to what the fuse rating should be if both are running together on the same circuit. Is that how it works?
​As for running time, I can't say definitively without an actual "road test" but I can't see it being very long, based on the distances involved.
From the seacock inlet to the flush pump would be about a meter. Then about 75cm back to the macerator and the last 25cm back out the outlet. So a 2 meter round trip.
I've also read about the need for a looped section on the plumbing depending on whether the pan is above or below the waterline and am wondering if removal of the tank will impact on this in any way. As factory fitted, there were no loops in the plumbing, as the pan sits just above the waterline. Assuming this will remain so?
Thanks again and if anyone has a schematic of the proposed double pole relay solution, I would be most grateful, just for clarity and a better understanding of same.

 

[Grandad]

Those motors both draw significant current. If they were on the same circuit you would need to add them together and then size your fuse at about 125%, then choose a suitable wire to carry that much current. So .. 15 + 16 = 31 amps x 1.25 = 38.75 amps. It follows that you'd use a 40 amp breaker and about a #8 AWG wire. A #10 would be probably be acceptable, considering these pumps would have a short duty cycle, but you may also need to consider voltage drop. The larger wire size would provide greater motor efficiency and possibly higher RPM. OK, the next problem would be that you'll have trouble finding a switch that will survive that much current draw on a motor circuit. Another consideration is whether you want both motors fed from the same 40 mp fuse that could make troubleshooting more difficult and might cause more damage if/when a small motor fails.

I always tend to overbuild things and a boat that's seldom in port is a good place to overbuild, so I'd individually fuse the 2 motors at 20 amps each on separate circuits, each on #12 AWG equivalent copper wire and control both simultaneously with a double pole relay with a contact rating of 20 amps or more. Most standard switches can handle the load of the relay coil and you might be able to simply use one of your existing switches and the circuit it is already wired from to control the relay. Sorry, I don't have a good drawing program to whip up a schematic, though I'd love to get one. And as for the plumbing issues, you can't drag me into that. - Grandad

 

[sogood]

Thanks for the wealth of information granddad. The more I look at this, the more I'm convinced to just reinstate the tank! It's out now, so access is easier to clean up the well it sits in, as well as fitting new hoses. The one change I will probably make, is to do away with the "Y" fitting, as the tank would always be, periodically emptied directly to sea, as planned. At least by sitting in the tank, the waste can be treated with the appropriate chemical additive. I would intend to run a new hose from the waste syphon cap, directly into the tank, as opposed to the "Y" fitting (appropriately set) to facilitate emptying dockside and to add occasional fresh water/chemical additive. It seems odd to me to have to syphon the tank via such a roundabout manner, as opposed to syphoning directly from the tank itself. Any thoughts?
This will also eliminate any complicated wiring issues, with the original separate circuits for flush and macerate/empty being left intact.
Many thanks again for all the inputs. A newbie like me can never be given enough information or opinions!

 

[mjf55]

sogood, i think that is a sound decision. You never know when a tank would be needed. I do recommend you plumb it as original, meaning put the Y valve back in.

Thanks for your update.