I've had one or two email from readers recently who though impressed by the electric head installation that I undertook a while back have been asking about other alternatives.
On all but the smallest of vessels having some form of sanitary facilities is pretty much essential and those facilities can run the gamut from basic to luxurious. On my first boat the toilet consisted of no more than a cedar bucket which was dumped over the side once it had been used. It worked very well I have to admit, there was no plumbing to worry over, it was cheap and anyone could use it with no instruction but it could hardy be called luxurious. It is also worth mentioning that non discharge areas had yet to be introduced and environmental concerns were not especially high in anybody's thoughts. Things have moved on somewhat since those days and with increasing environmental awareness holding tanks are now de riguer aboard every boat relegating that cedar bucket pretty much a thing of memory.
Virtually all coastal waters are non discharge zones making it illegal to dump raw untreated sewage into the water. This means that waste must be contained on board the vessel and later disposed of at a shore side facility. On all but the smallest of boats waste in contained in what is commonly termed a holding tank, a plastic or metal tank into which the contents of the toilet are flushed which is then pumped out when it becomes full at a marine or other facility that has the correct equipment.
The chances are that any new boat will come with a suitable toilet but what about older vessels or if you want to upgrade to something grander? For small boats such as center consoles or bow riders with a heads compartment built into the console the best bet is often the ubiquitous chemical toilet. In days gone by these were barely a jump up from the cedar bucket but modern versions have two separate tanks, one for flushing water and another for waste which can be detached from the toilet and carried ashore for disposal. Simple to install chemical toilets require no external plumbing and can be bought for less than $100 from your local marine or RV store.
For longer stays aboard or on larger vessels the next step up is the manual marine head which as it's name suggests requires no electricity to operate and unlike the plastic chemical toilet these have a proper china bowl. A pump is built into the side of the toilet which draws water into the bowl and flushes waste into a holding tank. Manual toilets are a good choice on sailboats that may have limited amounts of electricity aboard however when guests come aboard there is something of a learning curve for those not used to these types of toilets with clogging a common problem often due to insufficient flushing as waste may have to pumped some distance from the toilet bowl to the holding tank.
Electric toilets are simpler to operate and in may cases are no more than manual versions to which an electric motor has been added to take the effort out of flushing. More sophisticated models have programmable controls so that the flush cycle is timed thus ensuring waste is fully and completely sent to the holding tank. I recently installed an electric Raritan marine toilet on my own boat and can vouch for the simplicity with which the whole system works. With a simply the push of a button the toilet goes through the flush cycle so is foolproof even when we have non boating guests aboard.
The largest of boats that have two or more heads often have a vacuum system. Because pipe runs are longer electric pumps would have to run excessively to pull waste to the holding tank. This not only irritating because of the pump noise but holding thanks fill prematurely because more water is needed with each flush. A vacuum head works in much the same way as a toilet on a airplane; a vacuum is generated which sucks the waste using very little water into the holding tank. Often instead of a bulkhead mounted electric switch the head is flush by pressing down on a foot pedal on the base of the toilet.
So when the time comes to upgrade the toilet aboard which toilet will you choose? As ever it comes down to three things; the type of boating that you do, budget and what sort of boat you have.
If the boat is small you may well find that a chemical toilet is all that you need, cheap to install with no complicated plumbing. However taking a step up to manual or electric toilets fits the bill for the majority of boaters and is more akin to the toilet that you have at home but you will need more room for this style of head and don't forget that you will need to install hoses, skin fittings and holding tank if these are not already aboard. The costs for all this work and equipment can easily stretch into the thousands so it pays to do your homework, look at friends boats, visit boat shows and get an estimate from your marina or boatyard before finalizing you choice.