What kind exhaust do I have ???

[Laker]

Rather , what type do I have as a standby ? My existing system is a "good old" standpipe , almost exactly like the one pictured in the "no more fouled plugs" thread. I have been told that it would rust out , and it has , from the inside out. A JB Weld patch got me through my short season.

I have a different system on hand : a stainless steel can 7" in dia. , 7" tall , a single inlet vertical and centered on the top , and single outlet also on top with a 90 degree bend. Inlet and outlet are 1 1/2". I assume that the water & exhaust must be mixed prior to entering the can at the top.

What do I call it , is it a good system , and how should it be plumbed?

Sorry no pics , but simple description hopefully suffices ,

Laker

[ndutton]

Your backup is a waterlift and you are correct that water must be mixed with the exhaust prior to entering the 'muffler'. It will require a different hot section configuration from the engine and a vented loop in the water injection line. The final exhaust line will have to be routed as high as possible on its way to the transom.

I spoke with my stainless fabricator today and he is available to make standpipe mufflers. I emailed him the drawing I posted in the fouled plugs thread to get an idea of cost. Stay tuned.

[Laker]

Niel ,

Your response prompts a couple of question :

Would the routing of the final exhaust line need to higher than the one from the existing stanpipe? If so , why is that ?

Since you are suggesting that I consider a stainless standpipe , should I interperate that to mean that you prefer the standpipe design over the waterlift ?

All input welcome ,

Laker

[ndutton]

Your response prompts a couple of questions :
Would the routing of the final exhaust line need to higher than the one from the existing standpipe? If so , why is that ?

Assuming the existing exhaust hose runs from the bottom of the standpipe muffler at a downward angle to the thru-hull at the transom, my response would be 'yes'. The reason is unlike the standpipe, the waterlift will be lower than the waterline and unless the exhaust hose is run as high as the deck there's the risk of starting a massive siphon from a following sea or stern wake.

Since you are suggesting that I consider a stainless standpipe , should I interpret that to mean that you prefer the standpipe design over the waterlift ?

Since you have the available space for a standpipe system I prefer it for at least three reasons:

1. There is less exhaust backpressure than in a waterlift system, engine breathes better.
2. Unlike the waterlift, it's practically impossible to backflood the engine from a following sea. In truth, a properly designed waterlift system is pretty well siphon-resistant but less than the standpipe.
3. Also unlike the waterlift, it's impossible to backflood the engine with prolonged cranking (hard starting episode).

I believe the weak link in the original standpipe systems is the material from which they were made. In the era of our boats the vast majority were built to meet a price due to intense competition and iron was way cheaper than stainless, copper or bronze. Build it out of the right material and it should last a lifetime.

[Laker]

Ah.

Waterlift = waterlock , which is an entirely different plumbing concept that the one I now have. I am starting to get it. A replacement of the old standpipe with a new standpipe would involve a heck of a lot less work than plumbing a waterlift.

Could the waterlift be installed at an elevation similar to that of my existing standpipe , using it as an above the waterline exhaust & coolant water mixing vessel , rather than a below the waterline waterlock? Note that the discharge on my unit is turned 90 dg. , presumably for routing aft.

At this point I do not see the advantage of the below waterline plumbing plan... ?

My questions are obviously based on the fact that I am sitting on a waterlift unit ; a bird in hand , as the saying goes.

Laker

[ndutton]

Could the waterlift be installed at an elevation similar to that of my existing standpipe , using it as an above the waterline exhaust & coolant water mixing vessel , rather than a below the waterline waterlock?

At this point I do not see the advantage of the below waterline plumbing plan... ?

Don't have any experience with what you're considering, gotta stew on that one. If the waterlift is to be your choice, why not do a conventional installation?

I appreciate we're all cost driven. You also might want to compare the cost of changing to a waterlift even with your own muffler (new hot section, new mixer, new antisiphon valve, new water plumbing and new exhaust hose) vs. the cost of a replacement standpipe muffler without all the modification. Might even factor in the possible sale of the standby muffler you have.

The advantage of the waterlift that it's a system that works in restricted spaces. My Catalina 30 engine is located amidship under the dinette seat. Out there in the middle of the boat there's no way to route a standpipe above the engine. The waterlift is really the only option.

A well designed and installed waterlift system is just fine provided you are aware of its limitations such as the prolonged cranking problem. I'd guess well over 90% of us have it without issue.

[hanleyclifford]

I think Neil's estimate that 90% of the fleet is using the water lift design is probably real close. Now couple that with Don Moyer's estimate that half the fleet could be suffering from back pressure issues. The implication is that many systems are badly designed or maintained. The three advantages of the standpipe that Neil gave are likewise the three disadvantages of the water lift. After twenty years experience with the water lift system without incident, I would still go to the standpipe in a heartbeat if I had the vertical lift room available. Designing a water lift system will require a balancing act between safety and efficiency. As Neil and I go around on this we still have not come to any formulae that will give the optimal system, which indeed will be specific for each installation. But the standpipe is a no-brainer superior system and I would urge you to retain it cost notwithstanding.

[Laker]

You guys are helping me greatly in terms of understanding the basis of the two very different exhaust concepts. From what I now know , I agree with the assertion that the primary advantage of the waterlift is that it is applicable to situations dominated by space limitations , esp. i.e. a midship engine compartment.

I am certain now that I do not want to convert to the lenthy below-the-waterline plumbing arrangement. I can readily see how that may cause backpressure issues if not done correctly.

As time is on my side, (layup is soon), I will to continue to ponder the possibility of using the w/lift unit I have as a "mixing can" at the same location and elevation as my failing standpipe , and I welcome all input regarding that possibility.

Laker

[ArtJ]

Just a quick input My Tartan 34 Classic has the engine deep in the keel at
the centroid of the boat which gives it great recovery in a seaway without
hobby horsing at all. I believe the reason it has a standpipe is because
the engine is mounted so low.

As a different alternative, Tom Stevens of Indigo has the same boat and
for some reason elected to change to a water lift muffler and rerouted the
exhaust from the port side midship to the transom. This may have because
he wished the exhaust out the back rather than the side.

I had the bronze standpipe reconditioned (cleaned out) a number of years ago and it has been virtually trouble free.

Regards

Art

[keelcooler]

Laker may have a stand pipe system consisting of iron dry exhaust pipe brazed to a copper alloy mixer chamber. This system often fails at the bottom where the two metals are in contact. Art’s stand pipe system is all copper alloy (bronze) and will have the longest life expectancy.

For the boat builders it’s all about the bucks. They would have all installed water lift cans if available before the late 70’s. No more fouled plugs Joe did not elevate his stand pipe mixer, he eliminated a low sagging flex hose section from the stand pipe discharge to the transom exit. Once mixed in a stand pipe or jacketed system the discharge must run down hill or water in the sag low point will result in back pressure. This holds true for the water lift system also. The discharge from the water lift must proceed directly to a high point above waterline and then down hill to the transom without any sagging or low points that would allow water to stand.

Most back pressure problems w/ water lift systems revolve around flex hose inner wall collapse just after mixer, corrosion at the mixer and or poorly made mixer restricting the exhaust gas passageway. Remember that if you experience an overheating event you may have over heated the flex hose inner ply contributing to a restricting problem. An acid flush not diluted properly can also result in inner hose ply collapse. Only purchase good quality Shields or Trident exhaust hose. No made in China stuff allowed here.

Keep in mind a stack system is simply a mixer system high above waterline. No vented loop required.

[Laker]

Boy , I wish I had a bronze standpipe. If I did , I would not have started this thread.

My old standpipe appears to be welded iron ; it failed near the top. I was not too suprised that it failed , because after I finally started my engine while still on the hard I found a significant deposit of rust chunks on the concrete behind the boat. This evidence told me that problems were eminent.

"Keep in mind a stack system is simply a mixer system high above waterline. No vented loop required." (keelcooler) So , back to my question: since I have a stainless waterlift unit in my posession , but I am plumbed and set up for a liftpipe , is there any reason I cannot use the waterlift as a "mixer system" above the waterline?

Laker

[hanleyclifford]

No reason at all. You will simply be using a water lift unit that doesn't have to lift the water. The water pump will be doing the work except the exhaust will still be doing some "batching". FWIW you could actually just run your riser up in the same location as the old standpipe, install a "T" for the water, and then just run a hose downhill to the transom. The resulting "straight pipes" exhaust would not be as loud as you think and would give you a substantial power and efficiency boost--especially if you upgrade to 2" all the way from engine to transom!

[keelcooler]

Think about it. You will have about 6’ maybe more of red hot insulated dry riser pipe snaking up far above water line before it can be routed downward to the mixer and then to the water lift can. You will still need about 16”height between top riser and top of can because it’s a water lift, not a mixer. That’s a long heavy pipe run subject to vibration fatigue. Clearly it will require proper support arms. If it was a wise set up, it would be present on other boats. A surveyor may call the system a fire hazard.

You will need a vented loop because it’s a water lift, not a mixer. Just go for a nice traditional water lift system, after all you have a nice SS water lift muffler. That way the surveyor will say well done system, not what the hell is this, I’ve never seen anything like this and look for reasons to recommend replacement.

[hanleyclifford]

Keelcooler is right. The system will be long and require lots of wrap and if you make it out of black iron it will be heavy and require support at several points. If you have it fabricated out of something lighter, it will cost as much as if you just had a new standpipe fabricated. When it comes to re-engineeing on boats many things are possible but not always practical unless you just like to tinker and experiment (like me). That said, I must disagree with Keelcooler on the switch to a water lift system. On your boat that would be "de-engineering". Also I am not nearly so impressed by or concerned with the opinions of surveyors. The ones I have met are mostly used by insurance companys to determine eligibility for coverage. So you must also consider your long range plans for the boat. FWIW, if I were in your position I would get with Neil and his sources and have a new standpipe fabricated. Your could sell that water lift on this forum. Regards, Hanley

[ArtJ]

My Standpipe from Tartan34C

Attached is a couple of pictures of the bronze standpipe from my
1970 Tartan 34 Classic. Please note that I wrapped the bottom part
with stove pipe to shield the black iron from the plywood.

The green corrosion at the top I believe to be due towaterenteringfrom
thedrainabove