Sustainable Sailing

So having had a big grumble in my last post, Teak decks. The worst “luxury” “upgrade” ever, it is time for the opposite. A celebration of the best upgrade you can make to your boat.

The terrible pun in the post title probably gave away that the best upgrade is a composting toilet, the best option for all your number 1’s and 2′ 🙂

Composting Toilets win the “best” accolade for many reasons. Best for maintenance is a big winner, best for environment should be another, best for safety is pretty significant too. For many best for purchase cost will be important too. However, they are also best for guests and absolutely the best for COVID-19!

That is probably why I’ve mentioned composting toilets so many times on Sustainable Sailing, more than 10% of my posts include “composting” 🙂 So let’s review my claims:

Best for Maintenance

All the sailing channels on YouTube have plenty of videos which include traditional marine toilet problems. There are a lot of parts and plumbing. They get blocked, the pumps need servicing, bit get clogged with calcium deposits that need to be cleaned, hoses need replacing, seacocks servicing and of course all these jobs involve you dealing with sewage, often old sewage.

A side effect of this, that you only really appreciate after taking out all this out of the boat is how much better the whole boat ends up smelling. Especially true if your boat has a holding tank.

So how much maintenance does a composting toilet take? Very little. We have Nature’s Head toilets. If two of us are using only one of these and no other toilets then we have to empty the Urine container about once every couple of days and the solids every few weeks. If you have two toilets the solids have to be emptied much less frequently as they have longer to compost down. If you use one just for weekends then it lasts for months.

That process of emptying is really easy. Undo the latches, lift slightly and put the cap on the Urine bottle and just lift it out. No spills or smells. Depending on where you are and what your emptying options are you could just slot in an extra container and store the first until you can empty it.

The solids are also easy to deal with. Remove the seat, release the catches holding the base to the boat. Cover with an open bag and tip it up so that everything goes into the bag. At the moment we just bring the bags home and put it in a compost bin. If you are able to do this when the toilet has not been used for 48 hours then there is no smell. That is easy to manage if you have two toilets or only use the boat for weekends. Otherwise you can get a second base unit with a lid and so put the full one aside with the lid on for 48 hours.

Composting toilets vary. Some have no moving parts at all. The Natures head has a closing flap over the solids with a simple and sturdy lever to open and close it. Spares are available and it would be easy to bodge a repair. There is also an agitator which is a very simple mechanism. Spares are available and again something could easily be bodged. If both these broke it would not put the toilet out of action, you could manually sprinkle some compost on each time to cover the waste and there would be no smell.

But apart from these very simple things the toilet isn’t connected to anything else (you can connect a hose and fan, but it isn’t essential – we haven’t done so yet – it might gain you a few days between emptying as it helps dry solids more quickly). There are no sewage or water hoses, valves, holes in the boat etc.

The key reason why it is all so much less unpleasant is that the urine and solids are separated. That means you don’t get liquid sewage which is what really smells and needs treating and is potentially harmful. Also the whole unit is a solid plastic construction, it can be easily removed so that it and the compartment can be fully cleaned. It can be placed in a fully sealed easy to clean floor space, no need for access to seacocks, pumps, valves.

Best for environment

It turns out that keeping liquids and solids separate has fantastic benefits for the environment. If you have access to some land (such as weekend/holiday sailors typically do at home) then you can take both the liquids and solids home.

Urine, especially if stored for a few days and diluted with water is an excellent fertilizer, even safe on food crops. See the positive uses of Urine 🙂

If this isn’t an option then emptying it into a regular toilet or urinal is easy and allows for the normal processing (while wasting very little fresh water compared to normal use).

If that isn’t possible then emptying over the side of your boat outside coastal waters will have minimal side effects, in coastal waters where you might get higher concentrations there can be side effects from too many nutrients and also from pharmaceuticals that were not fully used by your body.

If you can compost the solids for over a year then they can be used on any plants including fruit and veg. Less than that then better to not use for food crops.

If that isn’t possible then after a couple of days the solids are safe to put with normal garbage. On long voyages either store (it is not a lot of space) or empty over the side while at sea (if they have been composting for a few days essentially it is just like dropping earth into the sea).

By contrast every other toilet system leaves you with either raw sewage or chemically treated sewage. You should not be dumping this ever in a river, harbour or coastal waters (legal restrictions do vary). So you either need to find a harbour where you can pump it out (what a lovely job) or you need to pump it in the ocean and remember this is quite different from the separate elements, this is sewage and it is highly polluting and very unpleasant.

We think dumping sewage into the sea should be banned everywhere. We are old enough to remember swimming from British beaches where you could find yourself surrounded by sewage, and remember the bugs that laid us low on holidays from this. The effects on marine life and the ecosystem are obvious and well proven. The only defence is that the quantities from each boat are small but that is a very weak defence and leaves sailors looking very bad.

Best for safety

Every standard marine toilet has a couple of seacocks, flushing water in and waste out (except for the incredibly wasteful ones that have a fresh water flush). So you have two fittings that are below the water line, generally tucked behind the toilet in a small compartment making access difficult. A failure here sinks your boat. A blocked valve because something inappropriate gets flushed can mean that you can’t shut it off. The risk might be small but boats sink every year due to seacocks being left open and hoses failing. Remember that if there is a problem then you are going to be trying to fix a leak while surrounded by sewage.

Best for purchase cost

Ok, there is a huge range here. But you can build your own separating composting toilet very cheaply (a seat, a couple of containers and a separator and a box to put it all in). Loads of plans available from the people who sell the separators eg from we-pee. Some go more basic which doesn’t seem very nice to use.

The cheap ones get “flushed” by simply dropping some compost or sawdust in after use.

We did build one of these and used it at home to test using a composting toilet before committing to buying them for the boat. After that we decided to go with a more expensive option (it seems that way until you price a complete replacement marine toilet and adding a holding tank) of buying a Nature’s Head. We felt that it would seem less scary to visitors.

We buy packs of Coconut coir briquettes for £10. In each pack there are 5 briquettes and each expands to 9 litres. In total that gives us about 25 toilet refills or a couple of years of full time use for two people. Beyond that a spray bottle with diluted vinegar is all that is needed for cleaning and stopping a calcium build-up.

Best for guests

Trying to explain how to pump a marine toilet to a new guest is difficult and error prone which is just embarrassing and unpleasant for everyone. It is also embarrassing and unpleasant for everyone when as will inevitably happen a guest blocks the toilet.

This is why we like the Nature’s head. It is really obvious. Open the flap before depositing solids, close it after and “flush” by turning the handle. No way can they block it up. Even if they miss it is easy for them to wipe with some toilet paper with no harm done.

Only lesson to teach is to get the men to always sit down (a few big waves soon encourage that anyway).

Best for COVID-19!

We had all taken for granted that when in a marina or in a boat yard you could just use their toilets. We forgot that you can’t use your marine toilet while ashore and that if you can’t move the boat in a marina and all the facilities are closed you will not be able to pump out your holding tank.

This is no problem with a composting toilet. Wherever the boat is, in the water or out of it, you can continue to use your composting toilet without needing any facilities from anyone else. Even if nothing else were available or permitted you can store the two separate parts without any smells or problems for as long as needed.

As we look forward to Wales opening up a bit and being able to visit Vida we are at a big advantage to everyone else because we do not need to have access to the yard or club toilets. Mother Ship Adrift Family Travel and Sailing Blogs were one YouTube channels who had real problems due to being in a boat yard in Spain during the lockdown when the boatyard were told they were supposed to close the toilets. No wonder in a recent video (21 minutes in) they were so excited by Rigging Doctors composting toilet.

Conclusion

Do not spend any more money on your existing marine toilet or holding tank or hoses, valves, seacocks. Instead as soon as you can rip it out and fit a composting toilet. Best boat upgrade ever 🙂