Fresh water problems

[LarsD]

Hi there,
I'm pretty new with boats and we have a 39 feet sailing boat that we bought late last season. We are slowly discovering the challenges of a boat from 1981. All in all she's in good shape but she's also in the need of getting a good amount of updating.

I have found several things that needs fixing and one of these is the sea water intake. The plumbing needs to be replaced - not to the standard I would want. The intake is at the head and we only open the valve when we use the toilet, normally it is closed.

Yesterday when at anchoring in our archipelago I left the valve open as we were below and I thought it would be convenient to be able to use the sea water outlet (manual foot pump) at the sink.

I didn't think more about this, only made a mental note of closing the sea water intake valve before lifting the anchor later.

My wife kindly brewed us some coffee and when drinking this we both realised a something was wrong. The coffee tasted weird...

I tasted our fresh water and that also had a foul taste - almost salty. We had filled our main tank (100 litre) the day before from our normal source at our home harbour so we could quickly rule out any contamination from there.

The water tasted almost like our sea water! We are in the Baltic so the water isn't very salty but I thought the tap water was not quite as salty as our seawater but certainly not our normal fresh water....

I din't know what to do so I started to trace the water piping in the boat (I haven't gone there earlier) and to my shock I found a pipe (well hidden) from the sea water pipe in the kitchen connected to the suction side of the freshwater system (the pipe from our main fresh water tank to the pump)!! The connection to the sea water pipe (T-connection) also had a shut off valve that was in an open position. Trying to close that valve I just realised it was stuck in the open position (not possible to close). In our normal case, with the sea water intake valve closed, the only water our water pump could get is the water in the tank but now, with the sea water intake valve open, I guess the water in our taps suddenly became a mix of fresh water and sea water - not very tasty to say the least...

Now to my question:
Before I just remove this cross over pipe and plug the both T-connections I just wonder why on earth someone once went to the trouble to build this cross-over between the two pipe systems? Has anyone else seen something similar or does anyone have an idea of why one would like to be able to either push sea water into the fresh water system or the other way around?

[crocks]

Maybe they flushed with fresh water. I've known people on the hard who also tap into the fresh water to flush the head.

[atoll]

was the boat ever sailed on fresh water lakes?

[LarsD]

Crocks: Quite possible. However I would have expected the toilet to h gave is own pipe then, as it is now the whole area water system would get its water from the fresh water tank....
Atoll: I don't know that, possible but most likely it was aimed for the Baltic sea.

[double u]

a lot of french boats in the 90ies (e.g. Feeling 446,...) had a galleyfootpump with a 2-way-valve to swich over from tank- to seawater. on seawater to rinse the dishes, on tank-water in case the waterpressurepump broke down

[geoffr]

It sounds like they plumbed it for a couple of options:

1. Head can use Salt or fresh water flush
- normally use salt, but if away for a while flush with fresh by changing the valves (both)

2. Sink can use Salt or fresh water
- when rinsing dishes use salt water, then flip the value to wash in fresh water.

Sounds like neat system, but not ideal. (better to have a second tap for salt water for dishes etc).

[LarsD]

Double u: interesting - might be something similar this then...

Geofr: There are separate taps for sea water with four pumps at the sink Iand at the head. Both places also have fresh cold /hot. don't know how the boat looked from the beginning though. Might be as you say and then they added the other taps later....

[double u]

sure 2 footpumps would have been better (as would have been vented loops...), but were apparently WAY too expensive for the Kirie yard (& charterguests only managed to break the footpumppedals anyway: seacock closed, 2-wayvalve on seawater - & 300lbs stepping on the pedal...)

[LarsD]

Originally Posted by double u

sure 2 footpumps would have been better (as would have been vented loops...), but were apparently WAY too expensive for the Kirie yard (& charterguests only managed to break the footpumppedals anyway: seacock closed, 2-wayvalve on seawater - & 300lbs stepping on the pedal...)

Shot happens... 😆

[double u]

..3rtws & never breaking a one (& no electric waterpumpson board) compared to 1-3 every month broken in a fleet of 32 boats makes you wonder though...
"what-do-I-care" happening more likely