Engine cooling system

[Lamby]

Hi i am hoping some one will be able to establish what cooling system my engine uses from the photos, i thought it used river water but now i am not so sure, i un done the filler cap on the heat exchanger ( i assume its a heat exchanger the first photo) however, water started to pour out so i re tightened it quickly an advice would be welcome.

[Tony Brooks]

Does water flow out of the exhaust or the side of the boat with the engine running, my guess is no and if so it is not raw water cooled.

The thing with the filler cap on doe snot have enough hoses on to be a heat exchanger so its just a header tank. This and the lack of raw water being discharged implies a skin tank.

The third photo seem to show a large bore pipe running into the bottom of the hull so that suggests that that are of hull is either a skin tank on the inside (normal) or there are cooler pipes outside the hull on the swim or a skin tank has been fitted externally.

I see that you have what looks like a calorifier feed from the front of the engine.

Unless the engine was warm/hot I would not expect water to flow out of the filler. In fact I would expect an air-gap above the coolant. However if the cooling system has been connected to something like a central heating system and there is another header tank somewhere then water may flow out when cold. the only other explanations are a leak between the domestic water and engine coolant inside the calorifier or an external leak into the skin tank/cooler pipes. In the former case I would expect the domestic water pump to run frequently  when turned on and water to flow from the filler cap all the tome the domestic water pump is turned on but thsi is not definitive if someone has been messing with pump cut out pressures.

 

[Lamby]

Thank you Tony that helps a lot, it has given me a starting point. very much appreciated.

Edited March 4, 2017 by Lamby

[David Mack]

Is that a skin tank on the inside of the right hand swim in the last photo?

 

[Tony Brooks]

It looks like it but no bleed points that I an see, however as the header tank looks as if is connected directly above it by a large bore hose it should be self bleeding.

[Flyboy]

How on earth did this boat get a BSS with that wiring ? Those wires adjacent to the exhaust are particularly asking for trouble.

Edited March 5, 2017 by Flyboy

[Lamby]

 I have been google researching skin tanks and now have a much better idea how it works. I am sure I will be able resolve issues. Thank you to both Tony and David for your help and supplying the correct name that enabled the research.

Flyboy I can assure you the boat has got its full boat safety history, for the 10 years it has been in my family. The wiring has never been highlighted as a concern with any of the various bss inspectors as of yet, however I take on board your thoughts and will look to address the issue you have highlighted, would not want any damage to the boat or owners due to easily rectified concerns. Thank you for bringing it to my attention. :-)