Cooling hose - narrow boat

[Northener]

I need to replace the hose which takes the coolant from the engine to the skin tank. (It might be tank back to engine, I’m not sure) It is the lower of the 2 hoses from Nanni engine to the skin tank. Just below the hose is the coolant drain plug. Can someone tell me how much coolant I will need to catch when I drain it. My engine is the 3 cylinder Nanni, 21hp. I don’t really want all the coolant in the bottom of the boat.

 

Also, any ideas where I could get a new hose, the hoses to and from the skin tank are bellows type, but I don’t suppose they have to be.

[Tonka]

10 minutes ago, Northener said:

I need to replace the hose which takes the coolant from the engine to the skin tank. (It might be tank back to engine, I’m not sure) It is the lower of the 2 hoses from Nanni engine to the skin tank. Just below the hose is the coolant drain plug. Can someone tell me how much coolant I will need to catch when I drain it. My engine is the 3 cylinder Nanni, 21hp. I don’t really want all the coolant in the bottom of the boat.

 

Also, any ideas where I could get a new hose, the hoses to and from the skin tank are bellows type, but I don’t suppose they have to be.

Midland Chandlers do hose for engine cooling. Not sure what you mean by bellows type though

[Northener]

Thanks for the quick reply. By bellows type I mean it is sort of concertina like. 
I am near Oxford and would like to pick one up tomorrow if possible. 

[BEngo]

Coolant hose is usually either fibre reinforced rubber hose of a suitable diameter, or reinforced clear PVC hose of the right diameter.  Miles of either/both on  the web in various colours.  Use stainless worm drive clips to hold it on.  

 

No idea how much coolant your engine and skin tanks hold.  You could work out the volume of the skin tanks by measuring them.  Length x height x thickness.  ABOUT six and a quarter gallons to a cubic foot. Or a thousand litres for a cubic metre.  Add about a gallon for the engine and another for any calorifier pipework.

 

N

[adrianh]

Braided PVC pipe is not really suitable for an engine cooling system as it softens when hot and antifreeze can affect the plastic making it go brittle and crack if flexing.

You ideally want marine grade fabric reinforced coolant hose, this is measured by the ID ( internal diameter ), usually 1.25 or 1.5 inch on a boat.

Try Pirtek or any large supplier of industrial hoses or marine supplier for this grade.

The corrugated version is more normal to the larger vehicle side of the motor trade so you could try any fleet vehicle garage or large plant hire company.

Always use quality stainless steel jubilee clips, 2 per end if you have room.

If you are draining down it is a good time for fresh antifreeze mixed with deionized water ( or the more expensive premixed type), always premix before adding, max 50:50 mix.

 

[Steve56]

This is the type of hose I always use. In my opinion one of the best. Not the cheapest but will probably last the life of the boat. You say your hose goes to the bottom of the skin tank so that should be going to the suction side of the pump. You just need to be careful that whatever you use cannot collapse when warm. That's the main reason for not using some of this plastic type hose.

[ditchcrawler]