Skin Tank Connections.

[Longjohn]

Hi, can anyone make sense of the two flow outlets on the bottom of my skin tank, my previous boat had just one inlet and one outlet but my new to me boat has two outlets, at the moment the vertical valve is closed and the horizontal is open, the lower connection is below the floor . The return pipe goes back to the water pump on my Gardner 2LW, just before the pump there is a take off and a return that feeds the gearbox oil cooler. Thanks.

[David Mack]

How do you know that the pipe heading down through the floor connects to the skin tank?

When you refer to vertical and horizontal valves, are you referring to the orientation of the valve shaft. Or the associated pipe connection?

[Tony Brooks]

I can't make sense of the pipework without seeing what is behind the lining etc. I can't see what the purpose of this plumbing would be. I think we need to see more of it, so possibly wider angle photos.

 

I am assuming the water pump is the ENGINE water pump as there would be in a vehicle and not a Jabsco type raw water pump.

 

It also seems that somewhere down the line there has been a misunderstanding, because with the flow AND return from the gearbox oil cooler on the inlet (suction) side of the pump, there is nothing to make the water circulate through the cooler. I can see that two smaller connections in that position could be a return from a calorifier and a return from the oil cooler, although I think most would use large bore end caps on the cooler and pass all the return from skin tank flow through it.

 

[Longjohn]

43 minutes ago, David Mack said:

How do you know that the pipe heading down through the floor connects to the skin tank?

When you refer to vertical and horizontal valves, are you referring to the orientation of the valve shaft. Or the associated pipe connection?

Thanks, i have had the floor up, the bottom valve is open.

[Longjohn]

36 minutes ago, Tony Brooks said:

I can't make sense of the pipework without seeing what is behind the lining etc. I can't see what the purpose of this plumbing would be. I think we need to see more of it, so possibly wider angle photos.

 

I am assuming the water pump is the ENGINE water pump as there would be in a vehicle and not a Jabsco type raw water pump.

 

It also seems that somewhere down the line there has been a misunderstanding, because with the flow AND return from the gearbox oil cooler on the inlet (suction) side of the pump, there is nothing to make the water circulate through the cooler. I can see that two smaller connections in that position could be a return from a calorifier and a return from the oil cooler, although I think most would use large bore end caps on the cooler and pass all the return from skin tank flow through it.

 

Thanks, yes im talking about the engine water pump, i'll post a few more pics.

18 minutes ago, Longjohn said:

Thanks, yes im talking about the engine water pump, i'll post a few more pics.

The pipe marked in yellow is the return from the skin tank, the two red marked pipes are from the oil cooler. the skin tank is directly behind the lining, unfortunately i dont have a wider view of the instillation.

29 minutes ago, Longjohn said:

Thanks, yes im talking about the engine water pump, i'll post a few more pics.

The pipe marked in yellow is the return from the skin tank, the two red marked pipes are from the oil cooler. the skin tank is directly behind the lining, unfortunately i dont have a wider view of the instillation.

 

[David Mack]

35 minutes ago, Longjohn said:

the two red marked pipes are from the oil cooler.

So with the centre valve closed and the other two open, cooling water is routed through the gearbox oil cooler, but with the centre valve open and the other two closed, the oil cooler is bypassed. Seems an unnecessary complication.

[Longjohn]

34 minutes ago, Longjohn said:

Thanks, yes im talking about the engine water pump, i'll post a few more pics.

The pipe marked in yellow is the return from the skin tank, the two red marked pipes are from the oil cooler. the skin tank is directly behind the lining, unfortunately i dont have a wider view of the instillation.

 

 

3 minutes ago, David Mack said:

So with the centre valve closed and the other two open, cooling water is routed through the gearbox oil cooler, but with the centre valve open and the other two closed, the oil cooler is bypassed. Seems an unnecessary complication.

Yes i see what you are saying but why have two outlets from the skin tank so close together and what would be the reason for being able to switch form one outlet to the other, the one under the floor is only a couple of inches below the one visible . Thanks.

[Tony Brooks]

I think whoever fitted it liked gate valves and complicated pipe work. No idea why there should be two outlets s close together.

[BEngo]

I think the idea might be to have a controllable  skin tank bypass, handy to warm things up quickly  or when the cut is really cold and there is no need for much cooling.  Can't really say without an overall picture, or a pipe work diagram.

 

Certainly the original builder either got a job lot of gate valves from somewhere, or deserved a bulk order discount.

[matty40s]

Is one perhaps connected to a radiator(s) in the boat....do you also have a diesel heater system (eberspacher/webasto etc) ...

[blackrose]

5 hours ago, Tony Brooks said:

I can't make sense of the pipework without seeing what is behind the lining etc. I can't see what the purpose of this plumbing would be. 

 

Conversely, I can't make sense of the lining and can't think what is purpose would be?

 

Presumably the skin tank is in the engine space  below the waterline. Why would anyone line that area in wood? How are you supposed to bleed the skin tank for example if it's all hidden behind plywood?

[Longjohn]

3 hours ago, Tony Brooks said:

I think whoever fitted it liked gate valves and complicated pipe work. No idea why there should be two outlets s close together.

Absolutely, there are gate valves everywhere.

54 minutes ago, matty40s said:

Is one perhaps connected to a radiator(s) in the boat....do you also have a diesel heater system (eberspacher/webasto etc) ...

No, the two outlet converge into one pipe that leads back to the engine water pump.

8 minutes ago, blackrose said:

 

Conversely, I can't make sense of the lining and can't think what is purpose would be?

 

Presumably the skin tank is in the engine space  below the waterline. Why would anyone line that area in wood? How are you supposed to bleed the skin tank for example if it's all hidden behind plywood?

The lining is purely decorative, there is a bleed point on the feed pipe, but without removing the lining i cant tell if there is one on the tank.

[blackrose]

The other thing I don't like is all that rigid copper pipework and joints. With all the vibration in the area I'd rather have flexible car heater hose. It's less susceptable to cracking and failing.

[Longjohn]

1 hour ago, BEngo said:

I think the idea might be to have a controllable  skin tank bypass, handy to warm things up quickly  or when the cut is really cold and there is no need for much cooling.  Can't really say without an overall picture, or a pipe work diagram.

 

Certainly the original builder either got a job lot of gate valves from somewhere, or deserved a bulk order discount.

Thats certainly a possibility thanks.

[Tony Brooks]

Just an observation. That looks a very low height skin that to me, so it must be very long. I wonder if it is, or once had a "trombone" type keel cooler pipe on the outside of the swim, but that does not explain the two outlets.

[PaulJ]

1 hour ago, Longjohn said:

Absolutely, there are gate valves everywhere.

 

Could have been worse- you could have inherited this one..took a bit of head scratching 😀

 

[Longjohn]

59 minutes ago, PaulJ said:

Could have been worse- you could have inherited this one..took a bit of head scratching 😀

 

Good God !

1 hour ago, Tony Brooks said:

Just an observation. That looks a very low height skin that to me, so it must be very long. I wonder if it is, or once had a "trombone" type keel cooler pipe on the outside of the swim, but that does not explain the two outlets.

It could well be, unfortunately because its all lined i cant see much beyond these connections, its going to take some more investigating . Appreciate your comments.

[Peugeot 106]

12 hours ago, PaulJ said:

Could have been worse- you could have inherited this one..took a bit of head scratching 😀

 

At least his are colour coded blue and red!

[David Mack]

16 hours ago, PaulJ said:

 

Is that an art installation? Bears about a much relation to plumbing as this does to traffic lights!