Mystery hose on a VP D4 series? What does it do?

[kennyh]

Hi all

I'm about to do a Rydlyme clean of my heat exchangers / raw water system but I'm stumped as to where a particular (existing) hose goes to on the starboard side of the engine.

The hose in question connects on to the Exhaust elbow and then drops under the block. From there I've no idea where it goes.

Can someone enlighten me as to its function?

I've got a few pics showing the hose connected to the elbow and and showing it dropping under the block.

Main question is, do I need to block it off, or some other action to ensure that my Rydlyme will be not just be thrown down the exhaust elbow?


1st pic showing the hose going / or coming from under the rear starboard side of the block.

2nd Pic showing it connecting to the starboard side of the exhaust elbow.

Ps. I'll rotate the pics in a few minutes once I get on a decent computer. In the meantime, rotate your head to the left ;-)

 

[baylabayla3288]

I had similar tubes on one of my previous boat's KAD 42s. It is there to reduce back pressure by providing a bypass of the larger water column in the exhaust pipe. It helps when starting the engine. At least it looks like a similar arrangement.

 

[jimmy_the_builder]

BB3288 gets the points:

 

[kennyh]

Thanks guys for the speedy and informative replies!

I can therefore discount the hose from my plumbing for the cooling system de-scale.

Cheers!