Tuesday, February 28, 2012

When disappointment is a good thing

Disappointments are never pleasing.  When they happen, they can seem like the worst possible thing.  But there are times when that disappointment can actually be the best of alternatives...

Referring back to a previous post, I have indeed found the blockage in our raw water system.  It was right where I thought it would be.

This is that end plate on the water-cooled exhaust manifold... from the inside. Where is the water inlet?  Exactly.  You can't tell.  It is completely limed over.

Here is the same plate with the lime chipped off.  There's that opening!

So I took the plate to the shop and pickled it in concentrated hydrochloric acid to get rid of the remaining lime.  And guess what I found?  The spud where the hose attaches was cracking loose from the attaching brazing (this is an iron casting, and it had been repaired already by brazing on a new spud).  And inspecting the spud itself, I found that it was paper thin.  So OK, time to replace it.

It was the work of just a couple of minutes to break off the old spud (that is frightening in its own right).  Then grind the old brazing down and braze on a new piece of 1" copper pipe (the old spud was steel).

But wait!

When knocking off the slag from the brazing exercise (using the correct tool: the handle of a pair of pliers...), I actually knocked a hole in the plate!  It's visible there in the photo.  Here's a better look from the inside:

And there is a crack there too.  Yup... your conclusion is the same as mine:  there isn't enough good metal left on this thing to put it back into service.

So, here's a case where a benign failure at the dock was a disappointment, but it was far better thing than if that end plate casting had failed out on the water somewhere.... and surely it would have.

Postscript:  I checked - I'd have to order a replacement out of England.  Instead, I have a local boat yard (Miller & Miller - I really cannot recommend them highly enough) fabricating me a new one out of mild steel plate.



Dougm said...

Disaster narrowly averted! Lucky catch.

M Nigh said...

As wise people say....Always better to be at the dock wishing you were out on the water rather than being on the water wishing(praying) you were back at the dock. This statement is even a bit more powerful for airplanes. Nice catch I will be anxious to see your path to finding a replacement. Parts still available?

Chuck and Jackie on SV Aria said...

WRONG!! Replace the whole exhaust manifold. If the end cap looks like that the manifold itself is no better. When it cracks/fails it will dump raw water into your engine through the exhaust valves. Needless to say that can be a lot more expensive than finding a replacement manifold.

bob said...

Mark -

Well said, and worth always remembering!

I have a local boatyard fabricating a replacement for me. Much easier than ordering such a simple part from England.

Chuck/Jackie -

I am considering it, tho I had the manifold out and had it checked by Stewart's Marine a couple of years ago. As you say, the consequences of a failure are severe. Stewart's quoted me $1610 for a new one (and no, it doesn't come with the end plate, so having it fabricated is not a wasted effort).


Deb said...

The link for Miller & Miller is not working. Can you check it and post it again?

S/V Kintala

bob said...

Thanks Deb - I have corrected the problem with the Miller & Miller link


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