Exhaust leak

[junaido]

A few years ago I saw a nipple section of pipe offered for sale online.  Maybe Westerbeke, don't think it was CD.  You could look to see if it's still around - just a nipple into a short pipe section, but I don't know if the pipe was threaded at the top end.

Good luck.

I think this might be the Westerbeke part, https://www.westerbeke.com/Product/NIPPLE/299693. I will probably go with the T unless there is some reason to use this part.

[KWKloeber]

As far as H2O the Wye is intended so that it's injected down so that exhaust pressure doesn't tend to push it "up" but tee will work. The limitation is the length of the nopple+tee+nipple— it makes it difficult if not impossible to get the hump hose on (on me boat I could NOT use it; your mileage may vary.

The tee could be welded to the ell and eliminate the nipple if length is an issue for your muffler.

Here's Moyer's:
https://moyermarine.com/product/inline-cooling-water-exhaust-entry-fitting-exht_01-1_324/

The one difference is apparently the seawater hose size but I'd think you could make it work.

If using pipe, I recommend nothing except Schedule 80 or stainless Sch 40 (never galvanized.)

See SteveD's article:
https://groups.io/g/Catalina30/wiki/12551

[waughoo]

My only suggestion would be to get a "street" 90 for that T so you can have the hose pointing down towards the tee fitting.  Not sure it is really necessary, but seems to me the way to orient it.

[Stu Jackson]

Alex,  there really is no need for a street elbow because by the time the water gets through the elbow it's going horizontally anyway and the elbow is just causing more pressure drop.  As an engineer, I believe it is probably not what you'd want.

I knew it!!!  The 101 Topics that I built has the link to the nipple:

Westerbeke Nipple Source  https://www.westerbeke.com/Product/NIPPLE/299693

[Ron Hill]

juna : The "T" should work just fine!!. 

I see the both you and Stu have the same URL for the Westerbeke Nipple!!! 

A thought

[waughoo]

True Stu... I suppose it just appeals to the artistry of layout.  That westerbeke nipple really is the bee's knees.  I'd buy that if I was doing my elbow out of black iron pipe.

[KWKloeber]

Has anyone confirmed what size seawater hose is the Wb injection wye?

[KWKloeber]

a "street" 90 for that T so you can have the hose pointing down towards the tee fitting.

***

the elbow is just causing more pressure drop.

It would depend on how the hose runs from the vented loop.  An ell isn't about a fair entry into the tee, it's about making a fair hose run back to the loop.

In my case (C30; yes I realize the 34 is different) it is directly above the muffler so a long sweeping bend in the hose is counterproductive.  If the hose run can be made fair to the vented loop vis aʼ vie gentle bends of the hose then that's prolly easiest to do that.

Either way, the flow is low for the size hose/fittings so any additional back pressure due to an ell will be insignificant because the velocity is so low (head loss is proportional to V; a 90 is equivalent to adding 12" of additional hose, or 6" if it's a sweep 90.)

A fabricated wye (for 5/8" hose) is best, it addresses
1) injecting the flow in the correct orientation.
2) orienting the hose in the correct direction
3) the excessive length of a nipple/tee/pipe length and installing the hump hose.)

Both CTY and Wb have already thought this thru, why experiment to prove the obvious for the sake of a few boat bucks?

[Ron Hill]

Ken : The exhaust hose from the vented loop is directly above the exhaust riser - so the hose goes straight down to the nipple.  There could be a slight 90 degree bend in the hose the a "T" nipple.

You could go to an auto parts store and find a short 90 degree 5/8" molded hose and attach it to the nipple!!

A thought

[Stu Jackson]

Here are some views of how it is all arranged under the head sink.  I made the hand drawn diagram well before digital cameras. 

[Stu Jackson]

from Catalina Yachts and a photo

[junaido]

Stu,

Thanks for the diagram and pic, I saw this hump hose on Amazon, seems like it would work? https://a.co/d/7yyALPo or https://www.ebay.com/itm/175392097964

Also that crinkly alum-silica heat shield, what is a good place to get that? Or can I just double wrap the upper section with the heat wrap?

Junaid

[Ron Hill]

Stu : Thanks for showcasing my hump hose and new muffler!!  Note the leather protection under the hose clamps - just to make sure they cannot cut into the soft hump hose!!

juna:  Don't know where you can get that crinkly heat shield, but a double wrap of heat wrap will work just fine!!

A few thoughts

[junaido]

I ordered the water nipple from Westerbeke, it doesn't appear to be stainless steel, but hopefully more resistant to corrosion than the black iron tee I was thinking of using. The exhaust flange gaskets are also available at Westerbeke. Part #: 298600 https://www.westerbeke.com/Product/GASKET/298600

[junaido]

What kind of thread sealant (if any) should I put on the various joints of nipples/elbows in the exhaust riser? Highest temp thread sealants seem to go to 400F. Over at the Moyer Marine forum there is some discussion that suggests that black iron will eventually rust and seal without any pipe dope.