EOTI Refit: Plumbing (new Dometic toilets and associated system)

If you are concerned about icky this post is not for you. When you buy a boat that is 18 years old it is going to have some issues. Everybody has their own personal tastes and that includes toilets. We are very risk averse and I don’t know if it is true but the marine head (toilet) is sometimes listed as the primary reason boats sink. When we bought EOTI we listed out about three dozen projects we wanted to complete before going off shore. I chatted through Instagram with Brian from Sailing Vessel Delos on the topic of their electric toilets. He said though they had video taped issues on more than one occasion the reality was that they had few if any problems. So I set out a group of requirements based on a systems of systems aproach to the refit of the plumbing.

  1. Decrease the number of through hulls (holes in the bottom of the boat)
  2. Match as close as possible standard home toilets for crew and guest comfort
  3. Switch to fresh water flush (further decreasing through hulls)
  4. Maceration and flush should be as quiet as a residential toilet
  5. The installation should reduce exposed mechanicals

There are two heads on EOTI. The stern head sits next to the shower and was replaced at purchase. It never worked correctly and we were concerned that something physical was wrong with the flushing (joker) valve. It would sometimes back wash into the toilet and fill with sea water. This is a really bad situation as the toilet sits about six inches below the water line.

The new toilet in the stern head sits on a beauty base to give it a sense of sturdy. None of the mechanicals are exposed and it sits about two inches higher than a standard residential toilet. Few people think about it but the close in nature of the walls is actually a feature. Nature doesn’t wait for calm seas. The last thing you want to do is try and use a toilet without something to brace on if the boat is heeled at 30 degrees. These toilets because they have no external connection to the sea are useable on angles of heel and because they pre fill with minimal water for flushing are ready to use.

The bow head was a mess. Upon purchase it never worked correctly. It was rebuilt twice and we weren’t sure what was wrong with the unit. It also would fill from the sea. It sits slightly higher than the stern head and you can see the ring that is created from that back fill which is slightly lower than sea level. We finally evacuated the head, cleaned it, and turned it off when we gave up getting it fixed.

The new head is exactly the same as the stern. A Dometic 8000 series electric macerating toilet. The installation is very clean with almost no mechanicals showing. It sits about 2 inches taller than a residential toilet. You will notice the towel bar or grab rail with wall for bracing. This toilet is also considered the day head (use by general crew through out the day). It sits at the primary bow-stern pivot point only being about two feet forward of the bast and at the point of the first keel bolt.

As part of the effort to replace, refurb, and fix things the holding tank gauge was replaced with new. This also required getting a new sensor. All the brands were kept the same with a Wema sensor and Wema gauge being the primary choices.

The new gauge from Kus is actually a Wema product under new management. A 16″ sensor was originally sourced but a reinforcement bar intruded on the space in the holding tank. We looked at bending, moving, or adjusting through main force the intrusion but decided to get a shorter 6″ sensor that will tell us when we have a few days of holding tank space left.

All of the sewage lines were replaced. A single hose runs from stern head to the 40 gallon holding tank and similarly a single hose from the bow head runs to the holding tank. This required the use of heat to create bends in the sanitary hoses. We also discovered that the run to the bow toilet to the holding tank was over 80% calcified (dried goo). Upon inspection we found the same for the stern head. The hoses were relatively new (2 years) so this was a bit strange. We think when the previous owner put the boat on the hard they simply dried up. The bends in the hoses from the last install also created traps.

In changing out the hoses we also removed all of the Y valves. The Y valve allows you in certain situations to pump effluvia over the side directly from the head. They also create another situation where water can get into the boat. In our situation we set it up so that you have no Y valves and toilet only flush to the holding tank. When we are sailing off shore we can empty the holding tank in about 3 minutes (as icky as it sounds). When in the Marina a service shows up and empties the tank in about 3 minutes for $1 a gallon. With our use and two people we get between two and three weeks on a tank.

Besides this is a good excuse to get beyond 3 miles (legal limit for emptying the tank) and go sailing. Worst case the team that shows up to empty while we’re in the Marine are great guys.

The hose run to the forward head actually took several hours to finish. The waterproof bulkheads of the bilge do not provide for a great run to the stern from the forward head. The pre-defined run means you have to be very careful to not get traps in the line. Our mode of operation is to flush the line by filling it with water whenever we don’t have our crew or guests on board. This is our preventative for the calcification of the lines.


Out of the gate we had to replace the macerator as it was acting a bit wonky. Where wonky is defined as tripping breakers, running slow, or having trouble keeping running. A new macerator is fairly cheap and we bought a spare to insure that we could fix things should we have another failure. With no Y valves and pump out facilities not always near by this is a critical component with a single point of failure. Some will be very upset with that single point of failure, but the reality is that legally it was ALWAYS a single point of failure.

To replace it quickly requires removing a hose on the side of it, and unscrewing the macerator unit from the T junction for the pump out.  That and the two wires connecting it along with 4 bolts are all you really need to finish the job. Though there is always a catch.

The T junction when you unscrew the macerator is 6 inches below the top of the holding tank. If you discover as the tank is getting filled the macerator failed the last time. You now have 6 inches of toilet stuff sitting above this junction. About 6 gallons worth. If you can get a pump out at a dock that won’t be that big of deal, but if you are running the macerator chances are that docks won’t be nearby.

So, for us this is a success story. We removed the Y valves, switched to electric macerating toilets, deleted three through hulls, and replaced or refurbished the entire system (except holding tank). We met or exceeded every requirement on the job. We feel that we have made the boat a lot safer by completely removing a cause of sinking. We have not had to significantly change our behaviors and we think a US Coast Guard inspection will find the two switches required to operate the macerator along with the through hull being close enough to meet the spirit of the law. We’ll put a lock on the through hull at some point too.

Service was provided by Griffin Yacht Services http://www.griffinsyachtservices.com in Fort Lauderdale. The work was quick, flawless, and required some pretty innovative thinking.

Total price for materials, labor, and travel was approximately $7000. No compensation, recompense, kick back, side bets, agreements, or other was provided by the service or companies involved. I pay what they say it costs and during this refit none of the companies involved knew I was going to mention them on my blog.