Which way round?

[PaulJ]

I was about to fit one of those cooling water inlet/strainer skin fittings with the "strainer" forward and the "scoop" aft when a friend said that he thought it should go the other way round..... Can anyone give a definitive answer as to which way round it should go.... please ?

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[GrahamC]

Your friend is right, but I do not think it would matter to much. The advantage is protection of the grid
GrahamC

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[petery]

Why use an external strainer?

Is fitting a strainer on the outside of the hull worth it?

We lost cooling water last weekend - the water was slowly filling the Vetus filter and then slowly emptying in 'pulses'. We tried to clear the inlet with a stiff wire which hit the protective grid from the inside - so the blockage appeared clear.

...but the problem persisted. In the end a crew member had to dive overboard and use a thin electrical screwdriver through the grid to break up a cluster of barnacles growing in the space between the grid and the actual intake. The cluster was acting as a kind of ball valve - being sucked up against the inlet; stopping the water flow and then falling back allowing another pulse of water to get into the cooling system.



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[seaesta]

Re: Why use an external strainer?

Where dya get a crew that will jump in the briny for you?
You must be rich or a leather clad blonde

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[anabel]

The scoop should face aft. It is supposed to divert weed away from the opening. However some years ago I dispensed with mine & I feel there has been an improvement and less surface area for barnacles to grow which is a major problem in my sailing area.

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[anabel]

I forgot to mention I also got rid of the little grid on the opening. The Vetus strainer inside is sufficient to strain any weed & you can see it when you take in any.

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[Strathglass]

How they are fitted depends on whether you are a raggie or a mobo.
On a motor boat they are turned to get maximum flow from forward speed as when moving forward the engine will always require cooling water.

On a yacht one hopes to be moving forward at some time without the engine running. The last thing wanted in those circumstances is for the forward motion of the yacht to cause presurised water to be pushed up into the filter and the raw water pump. The opening on the strainer skin fitting should be facing aft on a yacht.

Iain

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[PaulJ]

Many thanks one and all..... 'good job I asked innit!

The reason I wanted to fit a strainer results from an incident on a friend's boat in which just after moving off from the pontoon we got an engine overheat warning. Of course I thought that the skipper had forgotten to open the seacock and a quick look over the back confirmed that there was no water coming from the exhaust..... The boss was adamant that he HAD opened the seacock and indeed had checked the exhaust water...... To cut a long story a little bit shorter, twas I that went over the side and discovered the unsuspecting eel that had managed to wedge itself into the intake fitting! It was a perfect fit and I had a hell of a job to get it out, in fact we had to open the seacock and take the top off the strainer in order to break the vacuum before I could shift it! Anyway, the upshot is that I want a grill over the intake on my own boat so thanks to those who responded.

Paul.

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