Probably the simplest arrangement that is possible to have aboard a boat is the ‘bucket and chuck it’ method, a cedar bucket that is simply tipped over the side once you have seen to business. Whilst this still works well offshore it is no longer acceptable in no discharge zones and so something a little more sophisticated is required. In some parts of the world it is still perfectly acceptable to have a marine toilet that takes it’s water in flushes through the bowel and then discharges this complete with contents back from whence it came. It will be seen that this is only a slightly more sophisticated take on the bucket the only difference being that one does not have to hang over the side to empty the contents but for all intents and purposes it is the same. Indeed it was this arrangement that I had on my own boats for some time; coupled to a Lavac marine toilet which has no moving parts it worked perfectly. pipe runs were short and blockages non existent and the image below is copied from the Lavac site to show how it is arranged.
In recent time things have started to get a little more complicated and with the advent of no discharge zones it is almost essential to have a holding tank aboard to comply with USCG and EPA regulations. If the boat were to only be used outside no discharge zones then we could just have the no holding tank arrangement but because we have to travel through no discharge zones to get offshore then a holding tank is required. Also given that most recreational boats are operated in inshore zones and may may never operate or venture into open ocean a holding tank is a must.
I guess the simplest for of holding tank is a Porta Potti style chemical toilet where the tank is directly below the bowl; there are no pipes and waste basically travels by gravity to the tank where it can be emptied out ashore later. Porta Potti have got a bad rap over the years and summon up images of a smelly outdoor toilet at some remote camp site. In fact providing that a Porta potti is maintained well, the proper chemicals are used and it is regularly emptied they do not smell at all. They also make sense on small boat such as weekender where there is little room for anything else or on board a boat where the heads will only be used only very occasionally.
The next step up from this is some form of proper marine toilet and this is where things can get complicated and in fact are often made much more complicated that they need to be. I have seen all sorts of contorted pipe work for toilets, with discharge pumps, macerators, twin holding tanks, sharp right angle bends, pump outs and all other manner of arrangements. The fact is that the more pumps, pipe work and other parts that you have the system the more chance there is of it either (a) blocking up or (b) malfunctioning in some other way. But having said that many of the problems that can be encountered with the head are down to operator error. When guests come aboard especially those that are not familiar with marine toilets I make sure to show them how to work the toilet. Even then often because they do not want to wake other crew members at night they will not give the head the required number of complete pumps. What you have to be aware of is that the waste once it disappears from the bowl has to travel down a pipe to the holding tank. if the head is not pumped enough, the waste, instead of residing in the holding tank sits in the hose somewhere where it can either cause a blockage or start to smell. In most cases on boats that have manually operated heads you need 10 to 15 good pumps to dispatch the little (or big) blighters to the holding tank and thus flush the hose clean.
On the vast majority of smaller boats, those up to 50 foot say, sea water is the normal water used for toilet flushing. Used for good reason sea water is both plentiful and free but it is not ideal. Firstly sea water contains millions of tiny organisms that you can only see under a powerful microscope when these are flushed though a toilet aboard they enter an alien environment where they die. As they die they decompose and produce a sulfurous smell and it is this that you can often smell aboard especially if the head has not be flushed for sometime. Secondly sea water can cause severe calcification on the inside of waste hoses reducing the diameter and preventing waste from passing through. Also using sea water also means that you have to have a skin fitting and sea cock and as such this is another hole in the boat that has the potential for leakage and in extreme cases sinking of the boat if the hose fails. Far better in my book is to use a fresh water flush where water is drawn from the tanks aboard. Incidentally if you are worried about contamination you can use a check valve to prevent anything backing up but in practice this is unlikely to happen especially if you have a vented loop in the intake hose. Fresh water smells sweeter and without the little critters the sulfurous smell will not be present. Calcification is likely to be much less also although the waste itself can cause problems.
Going back to my earlier point about most recreational boats being used in inshore waters and no discharge zones that means that waste should go directly into a holding tank. Most boats are fitted with a Y valve which enables waste to either be pumped to sea, when outside the no discharge zones or with it moved the other way into the holding tank. If the boat is used on inshore waters then the Y valve will be always diverting waste to the tank and given that any valve is an obstruction to the flow of waste why no do way with the Y valve altogether and send the waste directly into the holding tank which has the added benefit of doing away with another hole in the bottom of the boat, the waste outflow which is normally inch and half in diameter. It will be seen as shown in the diagram that the system is very uncomplicated, pipe runs are unambiguous and there is far less to go wrong and get clogged up. Providing that the holding tank is emptied on a regular basis there should be no problem and in fact a 15 to 20 gallon holding tank holds a lot of poop, the average flush only uses 3 to 4 pints of water, and even on a weeks cruise a couple would be very hard pressed to fill that up.
Another point about the installation of toilets and that is that hoses should avoid having any droops in them where waste and water can collect, a steady downward slope to the holding tank is ideal and will ensure that blockages are almost impossible. On smaller boats toilets tend to be manually operated but I am a big fan of electric toilets as pressing a button makes sure that the toilet will be flushed properly with the correct amount of water and they are more akin to the toilets that guests find at home so they do not feel intimidated by them. Holding tanks must be vented to the outside of the vessel and this is normally achieved by having a small vent fitting on the topsides well above the waterline, this vent may or may not have a charcoal filter installed. On a closed system such as this the only other connection to the holding tank would be the deck pump out.
Installing a system such as this eliminates two holes in the bottom of the boat, does away with lots of pipe work and associated fittings, saves money and ensures that you will comply with USCG regulations. Should you ever decide to go offshore on an ocean passage then you can either supplement your heads with the cedar bucket or install a Y valve and waste sea cock.
Comments