Holding tank installation

When our new tank had arrived it was time to start with the holding tank installation. In the previous post about our holding tank we mentioned that the water tank we planned on converting to a holding tank leaked in the old weldings, not something you want for a holding tank. So instead we abandoned the water tank and bought a plastic septic tank instead. The reason for choosing a plastic tank was because of the price and because there are no welding that will leak.

The tank we bought was almost a perfect fit in the bilge, so we were really lucky there! Once we received the tank we have continued with the installation, and thought a lot about how the installation will look like.

The two pictures below show a visualization of our holding tank installation.

On our toilet we have a manual pump that will take the blackwater from the toilet through the orange hose in the picture to a three-way valve. From here we can either choose if we want the blackwater to go to the holding tank or straight out through the purple hose, this solution is something we will use on longer crossings. Otherwise it will pass through the green hose and into the tank. The toilet is located higher than the tank so we won’t risk having to much blackwater in the hoses, which decreases the risk of leakages and weird smells. The tank is 75 liters (19.8 gallons) so we will probably be able to use it for a while before it needs to emptied.

But when we do need to empty it our newly bought pump will suck out the blackwater from the bottom of tank via the grey hose. After passing through the pump it will go through the blue hose and out via the purple. Before reaching the purple hose the blue one takes a turn through a vacuum valve to make sure no sea water goes backwards in to the holding tank. The red hose is to ventilate the tank.

One thing that we don’t yet have is connection on deck so that we will be able to empty the tank through land. This is perhaps a later project, since now isn’t exactly the time to do holes in the boat as winter is soon here, plus we have more important tasks to do. We might have time to do it before we leave but we feel that it might be quite unnecessary for us.

What we have read the strictest blackwater regulations are found in Sweden and the Netherlands (for foreign small vessels, at least) for the countries we will be visiting. In Stockholm archipelago there are good facilities for emptying the holding tanks and they are spread out around the archipelago (which is really good!) but we don’t expect that this will be the case for most of the countries we will visit. If there is no regulations there will probably not be emptying pumps either.

Our holding tank is big enough to get us out from the coastline (and into international water if needed). It would of course be great if we could handle the blackwater properly always but that seems quite hard.

So, as a conclusion, we will add a connection if there is time for us to do so. As for the time we will spend in Sweden and Netherlands; we managed to sail this entire summer (and autumn) without a functioning toilet. There are usually a lot of outdoor toilets here that you can use instead if needed. So if we managed this summer without any toilet we can last a few weeks with a holding tank. For Netherlands, we will probably spend a lot of time in marinas, and there we can probably use a toilet if our tank is close to full.

Here comes some more pictures of how the installation actually looks.

We have some final hoses to connect before we are done with the holding tank installation, and we can check of one more item on our long list of things we want to do before our departure date.

Previous posts about of our holding tank work can be found under the tag: Holding tank.