Marine toliet system – Sealand VacuFlush 5000 toilet, J Series Vacuum Generator and 125 litre Wrengco sullage tank

The issue of sullage is an emotive issue on any boat and until recently it was no different on Lucey Blue. When we bough the boat both the toilets were relatively old and the sullage system undersized and poorly designed.

Nick replaced the port toilet and plumbing with a standard manual Jabsco toilet – simple, effective and reliable. The starboard system took longer to design and quite a while to install. Removing the old toilet systems was not a pleasant experience for Nick, however, it reminded him why it is important to do a job right the first time and probably resulted in the new toilet systems being overbuilt!!!!

After a bit of consideration, redesigning and recalculating we decided to install a new Sealand VacuFlush 5000 toilet, J series vacuum generator and 125 litre holding tank in the starboard hull. The old system consisted of an electric Jabsco macerating toilet and a 40 litre Vetus sullage tank (located under the double bunk in our aft cabin). The tank filled in no time, the pipes were always full of waste and the system smelt……yuk….

Ryan chipped in as always and provided some great instructions – incredibly realistic for a 4 year old. However, we also sought advice from Charles Parsons (Marine Advisory Services, Annandale NSW). If you ever need advice on marine toilet systems we cannot recommend Charles highly enough.

The new design has the Wrengco sullage tank and Dometic vacuum generator located in the bow locker with a single PVC pipe connecting the system to the VacuFlush toilet. No more standing waste, no more sullage near “inhabited” areas of the boat and simple access for maintenance etc.


After removing the old system, the first step was to install a shelf in the bow locker for the sullage tank. Nick had forgotten how much fun it can be grinding fibreglass and using resin in a confined space. With the help of a long snorkel (made from new [unused] toilet hose) he made it out of the locker alive after a few hours!!!




The next step was to install the PVC sullage pipe – carefully ensuring a consistent downhill slope from the toilet to the vacuum generator in the bow locker. The PVC air vent piping runs uphill from the holding tank through the bow locker bulkhead, then under the headliner in the forward cabin to the anchor locker where it connects to a carbon filter before it finally vents to a point under the bridge deck (or when at sea to a point in the anchor locker itself).

With the shelf in and plumping in place it was time to install the Dometic Tank Watch 4 monitoring system into the sullage tank before connecting the vacuum generator and tank to the rest of the system. The Dometic Tank Watch 4 is great – no more guessing (and crossing your legs) if the tank if empty or nearly full!!!






The sullage tank is mounted high in the bow locker and has 1 ½ inch drain at the bottom that is split into two 1 ½ inch Vetus impermeable sanitary hoses– one to the through hull fitting and the other to the deck-mounted pump out fitting. Very simple and very, very quick to empty – no pumping just gravity drain or suction from the pump out station vacuum.


While the job sounds simple enough the boat looked like a bomb-site for several weekends with bits of plumbing, electrical wiring and bolts everywhere….



Emily and Ryan helped out passing tools, finding parts and pulling wires through hard to reach corners of the boat. By the end of most days they were tired and ready for a treat or two!!!!




Before too long – but what felt like an eternity to Nick – the “tank” end of the new toilet system was complete and it was time to get onto the toilet itself. This final stage was relatively easy – unwrap all the components, install the base funnel, bolt the toilet to the base and attached the water supply. The hardest part was tightening the bolts “in reverse” while working upside down in hard to reach corners using a mirror – by 22:30 in the evening Nick found it hard to crack a smile.




We are really happy with the new VacuFlush toilet and tank setup. The VacuFlush uses very little water and thus the holding tank lasts much, much longer than normal. Dometic claims a VacuFlush system connected to a 100 litre sullage tank provides the same number of flushes as a 400 litre tank connected to a typical electric macerating toilet.

Overall we think we made the right choice – the system is very easy to use, simple to maintain, quiet, efficient in terms of power and waste storage and best of all it does not smell!!!!!!