Home Ask the Expert Ask the Experts: Marine Toilets

Ask the Experts: Marine Toilets

by Norris Comer

“If you’re embarking around the world in a hot-air
balloon, don’t forget the toilet paper,”

—Sir Richard Branson

Full disclosure, I personally love the topic of marine toilets. I remember well my college days living aboard a recently acquired, beat-up 1973 Catalina 27 in St. Petersburg, Florida as a new boat owner and water life novice. While attempting to replace the rusted-out mounting bolts of the trusty, pump-action Raritan macerator head, I accidentally induced a small, continual flood of water from where the ancient, crumbling bolts had created a crude seal that I had broken.

No problem, I was sure I could shut the seacock to stop the flow of water, right? Well, it turned out that the thru hull valve was corroded open and could not be closed. My boat was essentially pipelining water aboard. The growing leak at the base of the toilet was also a bad time to learn that this boat, true to 1970s boating practice but illegal in 2012, had no holding tank. What was supposed to be a basic replacement of old bolts at the base of a toilet turned into a shipwreck in the works.

As my feeble duct tape fixes failed and the water, flaked with organic matter decades in the making, tasked the bilge pump, my chuckles turned into bitter swears. Was this the end to my sailing career, reduced to ruin by an old toilet? I ultimately leapt overboard with a rubber mallet and drove a wood plug into the thru hull opening. My sailboat stayed that way for quite some before I rallied the willpower to revisit the issue.

I share this story to reinforce the case that a boat’s marine toilet is important. Notice also that I’ve been saying “toilet” instead of “head.” For the record, toilets are called toilets at sea, for a head is simply the nautical term for bathroom. In other words, you will find the toilet within the head. This esoteric point was brought up to me by Court Percival of Monkey Fist Marine, LLC, a marine service company that operates out of Elliott Bay Marina in Seattle. Percival has decades in the marine business under his belt, and has been the marine toilet guru at Monkey Fist Marine since 2004. I picked his seasoned mind to untangle the fascinating, and important, world of marine toilets.

Q: In short, what are the different kinds of marine toilets available to a boater on the market in 2018? What does the array of systems look like?

Broadly speaking, you’ve got the classic manual macerator-style toilet, you’ve got your electric flush toilets, compost toilets, and the VacuFlush. Some models from Head Hunter are a slightly different breed, one that uses water pressure, called the Royal Flush. It uses a water-jet type of technology; a series of valves and the boat’s water pressure system to whoosh it through like a water jet. It’s kind of like what you’ll find in a urinal or public bathroom.

Monkey Fist
Marine LLC

Monkey Fist Marine, LLC is an Elliott Bay Marina-based marine service business that offers engine service, transmission service, diesel and heating systems’ repair and upgrades, plumbing systems, electrical systems, electronics, general installations, haul-out related services, inflatable and outboard repairs, diver services, and more. Owned and managed by industry veteran Jim Brown, Monkey Fist Marine, LLC can handle most boat-related jobs

monkeyfistmarine.com // 206-285-2600

Monkey Fist Dockside Offices

Q: You were talking about VacuFlush technology. How exactly does that work?

The original design was by Mansfield back in the 1970s, and they used a vacuum pump and separate accumulator tank. Now they have what is called a vacuum generator, the VG2 model and now the VG4 with a much quieter motor.

The basic design is that you have an accumulator tank of some kind and a pump that’s mounted in the engine room or wherever, and it works kind of like an airplane toilet. You turn that machine on, it pumps to create barometric pressure in the system, eight to ten inches of mercury (unit of pressure equal to about 30 millibars of pressure). When you depress the foot pedal, the barometric pressure equalizes (as per Dalton’s law of partial pressures, P1V1 = P2V2) and, whoosh! The contents of the toilet get sucked in the system.

As the system rebuilds its vacuum, the system cycles through until the line is clear. One benefit of this system is that the line is completely cleared of waste, and that results in less head odor and less water use. The average macerating toilet uses a half gallon or more of water per flush, while the VacuFlush toilets use a pint or two depending on how long you depress the pedal. For boats with the necessary room and that can provide the power consumption for the generator, VacuFlush is the way to go.

Q: When it comes to VacuFlush, space and power consumption can be the limiting factors?

Yes, although VacuFlush does draw a lot less power than even smaller electric toilets. Most Jabsco electric toilets, for example, require a 20-amp fuse, while a vacuum flush toilet usually just needs a 10-amp fuse. The vacuum flush draws considerably less power. Compared to a macerator style toilet, they also have less water draw. But you do need more space for the equipment.

Q: Have you seen a progression of marine toilet technology over your boating career?

The technology has certainly come a long way. Compost toilets have appeared in various forms over the last 10 or 15 years, and VacuFlush has also improved. They keep coming out with new, clearly improved versions of their vacuum generator products. The new ones have larger components that are easier for us technicians to work on, and generally are quieter and have fewer problems.

A lot of the electric toilets have evolved too. These days, some models are pretty fancy. You can get heated seat warmers, bidets, push buttons… those kinds of things.

Most marine toilets that I see when you talk about very mainstream products, like the Jabscos and Raritan PH2s, those pump macerator toilets have been around without significant changes since the 1960s for a reason. On the larger boats, toilets tend to be the modern, electric and VacuFlush variety, but the smaller sailboat or runabout toilets have been doing fine for 40 or 50 years.

Q: Are the classic pump-action Raritans holding up just fine in the modern era?

I would say, hands down, that Raritan’s PH2 is the best macerator, manual toilet for most small boat or sailboat
applications. Those are doing just fine.

Some of those Beneteaus and the like are molded around the head, so there isn’t space to install a VacuFlush-style marine toilet. They need larger bases that don’t fit in the typical head for a 35’ to 40’ sailboat. Throw onto that the fact that sailors generally don’t want complicated, power-consuming devices, and those classic compact manual designs are still very popular.

Q: It sounds like the ideal toilet differs depending upon what kind of boat you’re working with. Marine toilets are not a “one-size-fits-all” kind of industry?

Absolutely, there are many different models out there for a reason. Often, you’ll simply have to use an electric-style toilet because you don’t have the space for a vacuum flush, for example.

Q: Do you have any pro tips for those who want to reduce odor? Any secret aces up your sleeve?

Well, it sounds simple, but keep that tank empty. Really, don’t use the boat over the weekend and let it sit for two weeks. Even if you use the toilet only three or four times, that will create odor if it is left to sit for extended time.

Court Percival
Court Percival

Court Percival has been boating his entire life. An active Sea Scout, he grew into the Seattle maritime industry and has been working with Monkey Fist Marine LLC since 2004. His typical day includes a long list of in-water projects. Percival currently owns an Islander 36 sailboat.

“When did I get into boating? My parents bought their first boat when I was two, and I was always helping my dad fix it up,” Percival says proudly.

Empty and flush it, often. When you do flush it, don’t just flush it once either. Flush it two or three times with freshwater. I see folks who will sit there and fill it completely with freshwater, then pump it out before filling it 100% again. That’s unnecessary, you only need to fill it up a quarter of the way. All of the crap, literally crap, is at the bottom of the tank, so you only need to fill it up a quarter or the way, wait, and pump it out. Repeat one or two more times, and you’re golden.

There are a few additive products that I like. NOFLEX is a great powder digestor that is commonly sold.

Q: Is there is something to the additives? It’s not just a gimmick?

Additives are great, but what I do find is that people will use multiple additives at once and the enzymes will compete with each other. Just use one of the additives as instructed at a time. NOFLEX is great for short-term use, but the enzymes only live for 24 hours. If you’re going to let the boat sit for an extended period of time, K.O. Kills Odors works well. I’m not pushing any products, but these are some that I recommend.

Q: Let’s talk about compost heads. You seem kind of unconvinced based upon what you’ve seen. What do you have to say about them?

Compost heads are a really nice concept, but I haven’t seen them large enough to handle the use of two people for an extended trip to say the San Juan Islands or what have you, largely due to a lack of needed air flow. Bottom line is that boats don’t move fast enough for extended periods of time to create the necessary air flow of adequate circulation. Also, the compost units I’ve seen aren’t very large and can’t hold much before being full.

Q: A lot of compost models I’ve seen have tried to cut out the holding tank entirely. Would a compost system with the capacity of a holding tank work out in your opinion?

They’ve tried that years back in the 1970s. Hatteras had a Weir Skimmer kind of system, which is basically a very large tank where you put your deposits on one end and it travels through a series of three different compartments. The solids are transfer to one spot, the liquids to another, and by the time it gets to the end, clean water goes over the side. This technology actually came from trains and is still used today.

The problem is that boats don’t go 60 miles an hour, and that’s important for the necessary airflow. These systems are run by gravity, which also requires the waste to be a solid mass. The macerator toilets used in the marine sphere reduce the waste to fine particulates, which doesn’t work as well with the gravity-fed approach.

Q: It looks like we’re heading for a Puget Sound-wide No Discharge Zone for recreational boaters. How will that effect what kind of marine toilets you work with?

t I’m fully in support of the proposed Puget Sound No Discharge Zone. With the facilities that we have these days and the better technology boaters have at their disposal, there’s just no need to flush it all overboard anymore. It’s not necessary; it isn’t the 1970s anymore.

How does this legislation potentially effect my business? I’ve never been a big proponent of systems that treat sewage aboard, so it’s all in line with my marine head philosophy. Those overboard systems have always been persnickety and never worked properly. What’s more, they require saltwater to work, so if you’re boating on Lake Union or something, it doesn’t even treat the water properly before it is dumped. I’ve heard people say that they’ve been using their Electric-Sani for 20 years and it’s never given them a problem. Well, good for you, you’re the one motoring away who doesn’t have to deal with the mess.

I’ve always had the stance where we should install a complete system with a tank and do it right. This Puget Sound No Discharge Zone is a long time coming.

Q: Do you see any marine toilet industry-disrupting technology on the horizon? Are you anticipating going to a boat show and being floored by a product because “holy crap (pun intended) they actually DID it!”?

I think, as time goes on and we keep getting greener and greener, that a composting style toilet will become more popular and emerge as the industry favorite. It’s kind of like electric motors for boats, because green is in demand for boaters. The next trend setter will probably be the ecologically-minded compost system that many boaters have been waiting for.

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1 comment

scott October 28, 2019 - 06:50

i just bought a tmc marine head and a jabsco electronic valve to install the toilet into a pressurized fresh water system on my boat.. can someone email me drawings on how to nstall properly… rehobothstar@aol.com


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