Sailboat renovation

Holding tank – part one

After we sailed back to the city the first thing we did was to clean the boat up, taking down the sails, remove all the fabric inside etc. After that was done we started our first major project for the autumn, making a holding tank. As mentioned earlier we have read that in most countries there is no regulations towards holding tanks, but in Sweden (and some other european countries as well) it is if the boat has a toilet, so we will need a holding tank. It is not only because of regulations we want to have a holding tank, it is also nice to be able to swim close to the boat and empty blackwater away from anchorages and marinas and not just let it straight out.

We have thought a while what kind of holding tank we want. Our first thought was to weld a new tank and place it above the waterline. Then we would use gravity to empty to the water and connection towards deck to empty on land.

But after some thinking and investigation about this we decided to convert on of our three fresh water tanks and use it as a holding tank for black water. That fresh water tank is located close to the toilet. It is below the waterline so we will need a pump to be able to empty it.  But it is located below the toilet so we won’t risk having blackwater in the hoses from the toilet to the holding tank, as we would have with our first idea (then the tank would have been above the toilet. If you want to see an overview of our tanks and the sailboat, see the pictures on the page The Boat.

So when we had decided which solution to go with, it was time to take action. First up: removing the water tank.

Preparing to take out the water tank.
Water tank out of the bilge.
And we are out of the boat.

The tank already has connection for filling the tank and venting, but we need a new connection for emptying the tank, so time to make a hole in the tank.

holding tank

holding tank
A new hole made.

The tank is custom fitted for the bilge, which means that it is not possible to have a connection for emptying in the bottom of the tank. Instead we will use a pipe on the inside of the tank to be able to take blackwater from the bottom.

The pipe we will use to suck up blackwater from the bottom of the tank.
holding tank
Adjusting the pipe so that reaches the bottom.
Welding time 🙂
holding tank
The pipe + the muff in position on the tank.
The pipe inside the tank. The small pipe seen in the picture is the old pipe for the fresh water, which we had to cut in order to make room for the bigger pipe.
Here we will pump black water up from the bottom of the tank.

Next up will be to continue welding, test the pump, do some pressure testing on the tank and getting the tank in position together with the pump and all fancy hoses we just bought.

Continuation of our holding tank work can be found under the tag: Holding tank.


Leave a Reply

Your email address will not be published.