Beneteau ST 44 potential sea water intrusion

[LarryM]

Volvos don't seem to be Fun on the Water

But Cummins sure are

This is what I found when I opened mine. New turbos and a complete re-design of the exhaust risers is now underway. Gotta love those boat designers

 

[BruceK]

Volvos don't seem to be Fun on the Water

Seems to be a Volvo/Beneteau ST joint effort imo.

 

[sunchaser]

So the question remains. Is this exhaust water intrusion caused by faulty engine design or boat builder wet exhaust system design? Some very smart TF folk suggest Beneteau. Beneteau suggests Volvo. Volvo suggests Hurricane Irma in one case or boat just sitting in another.

Larry M has a revamped exhaust system going into his Cummins powered Wellcraft. A read of boat diesel and a variety of fairly decent magazine mechanical experts talk to numerous good and bad exhaust system designs. It seems evidence is pointing to the Beneteau 44 (other Bs too?) requires some first class exhaust system help.

 

[boater3]

Turbo pressure is about 65 each, WOT.

Wow mine only go up to 30-35 at WOT...

 

[rclarke246]

Sorry, I gave you incorrect info, 34 is my max.

 

[rclarke246]

The difference between the waterline and the low spillover point on the exhaust near the engine measures about 18”.

This seems to be a good design unless I’m missing something.

 

[DavidM]

The difference between the waterline and the low spillover point on the exhaust near the engine measures about 18”.

This seems to be a good design unless I’m missing something.

Yes, that is a good design. But also look at the exhaust outlet from the lift muffler to the transom. It should go up and then back down to the transom, but it should not go up as high as the spill over point from the engine to be "inherently safe". This will let any water that builds up in the lift muffler flow back out the exhaust before it can get high enough to back up into the engine.

See the attached diagram. Should be fairly easy to fix. Just reroute the exhaust.

David

 

[boater3]

I'd be curious if us ST44 owners have the flapper and check valve...I don't see a flapper on mine... I don't plan to mess with the turbos or tear them apart right now as they seem to be operating well but as I near the end of my warranty I will likely have them opened up to take a peak, maybe one year before the extended warranty period expires. One of my dock spaces is on a river and while the stern is not positioned where the tidal change would force water against it, there are definitely slips where that is possible. I would be concerned that if the tidal current is not enough to force water in that potentially some wind could in some of the other spots. I actually never thought about this until the other day and will make sure I get a slip that does not put the stern in such a position.

 

[twistedtree]

Yes, that is a good design. But also look at the exhaust outlet from the lift muffler to the transom. It should go up and then back down to the transom, but it should not go up as high as the spill over point from the engine to be "inherently safe". This will let any water that builds up in the lift muffler flow back out the exhaust before it can get high enough to back up into the engine.

See the attached diagram. Should be fairly easy to fix. Just reroute the exhaust.

David

And don't forget any sloshing effect from any water that does accumulate. That could splash up to the turbo, depending on conditions.

 

[MichaelB1969]

The difference between the waterline and the low spillover point on the exhaust near the engine measures about 18”.



This seems to be a good design unless I’m missing something.

The one thing Beneteau has going for it is volume. It's helpful for identifying such issues. There are a lot of ST's around the globe.

 

[boater3]

The one thing Beneteau has going for it is volume. It's helpful for identifying such issues. There are a lot of ST's around the globe.

They have the volume but some times issues take years to surface and i think their first production runs only started hitting in 2012/2013. Some times issues surface a lot quicker. I.e. Carver had a major exhaust design issue on their C34 line and people found out pretty quickly because of a sensor. By the way, what is the sensor on the newer Volvo D4-300 on the exhaust? I think its only present on the 2015 ST 44 and newer...

 

[boater3]

So I have been saying that I will have my turbos opened up before the Volvo warranty expires in a few years (I bought the extended) but then I realized I should have them opened up probably before the Beneteau three year warranty expires in case there is finger pointing. Well last night I climbed into the bilge and hit into the port exhaust hose that goes from the engine to the muffler and what did I hear but a big whoosh sound. It sounds like there is water in the hose when I shake it. The starboard I could not getting any sound out of but it is also a shorter run. I am assuming this is a bad thing if there is water sitting in that hose?

 

[sunchaser]

Mystery

Does your water lift have a drain plug? If yes, open it a measure amount of water that drains out. Secondly and with an undrained water lift, pull the top hose and measure water level in muffler.

Ideally the water lift should be about 1/3 full when at rest.

 

[Ski in NC]

Take the mixer off the turbo outlet and see if inside of turbo is damp.

 

[boater3]

Mystery

Does your water lift have a drain plug? If yes, open it a measure amount of water that drains out. Secondly and with an undrained water lift, pull the top hose and measure water level in muffler.

Ideally the water lift should be about 1/3 full when at rest.

I will have to look for drain plugs but I dont think there are any. I am attaching a picture this time to show the hose (water lift?) from the engine to what I assume is the muffler (is that correct?) and some comparison/narrative of port v starboard (click to enlarge picture so the text is readable). If water should be there then that is some relief. Thank you.

 

[DavidM]

So I have been saying that I will have my turbos opened up before the Volvo warranty expires in a few years (I bought the extended) but then I realized I should have them opened up probably before the Beneteau three year warranty expires in case there is finger pointing.

Of course there will be finger pointing. Beneteau built a poor exhaust system and Volvo signed off on it.

But first cut a few inches off the exhaust to remove the dip and while you are at it check the turbo for moisture as Ski suggests. If you observe moisture you might as well start your warranty battle now, because the turbo will corrode.

David

 

[boater3]

Of course there will be finger pointing. Beneteau built a poor exhaust system and Volvo signed off on it.

But first cut a few inches off the exhaust to remove the dip and while you are at it check the turbo for moisture as Ski suggests. If you observe moisture you might as well start your warranty battle now, because the turbo will corrode.

David

How do we know Volvo signed off on it? That would be great if they did..

I don't want to be messing with something under warranty so will let a Volvo tech shorten the hose and open the turbos to check for moisture..

thank you all!

 

[DavidM]

How do we know Volvo signed off on it? That would be great if they did..

In general for any new production build and with many repowers, the manufacturer sends a rep out to look at the installation: exhaust back pressure, exhaust geometry, propped ok, etc and signs off on the installation.

Don't know specifically if Volvo did this on this boat, but that would be the norm.

David

 

[boater3]

In general for any new production build and with many repowers, the manufacturer sends a rep out to look at the installation: exhaust back pressure, exhaust geometry, propped ok, etc and signs off on the installation.

Don't know specifically if Volvo did this on this boat, but that would be the norm.

David

Thank you for that info!

 

[Ski in NC]

If the hose has a low spot, it is normal for that to hold some water. And it should not cause any wet turbo issues. I would not design one that way, but don't see any inherent risk.

Still would like to know if turbo is wet inside. If so, time to nag Beneteau while warranty is in effect.

 

[yellowbeard]

And if you follow boatdiesel for long, you will hear of many situations of sea water intrusion corroding turbos. I'll bet that at any one time there are 1 or 2 active threads on this topic at boatdiesel and at least a dozen new ones each year. So boat and engine manufacturers aren't doing much to avoid bad exhaust installations.

There are also many, many boat owners who replace their turbo thinking it is a consumable item. In almost all of these cases it is due to sea water intrusion and they have no clue what is happening. Turbos rarely die a natural death.

David

Caveat that I'm noob, but still amazing to me, that proper exhaust riser design information published 20+ years ago is still not being adhered to by major builders. Or, I suppose the builder in this case had a subcontractor install the exhaust system without knowing what they were doing? Volvo probably just delivers the engines and that's that. They obviously didn't take any stock in the exhaust system upon turbo replacement by blaming the weather. Not in their scope I guess.

The Defever with its 2' high loop is enough to pretty well insure that no wave will back up into the lift muffler. But if it possibly did it could back up to the turbo if the muffler filled over time.

So the Defever design is good, and it works, but due to its geometry it isn't inherently safe like the picture.

David

Yeah, looks like the stern would have to swamp so severely that the bow would be sticking straight up in the air. Bigger problems at that point...

 

[rclarke246]

Well, I continued to have trouble with seizing turbos. Volvo rep recommended new risers so I followed their lead.

Here is a photo of the new ones, with a totally new design. No need for the insulation pads and there looks to be a brass drain plug.

So far, so good.

 

[boater3]

Well, I continued to have trouble with seizing turbos. Volvo rep recommended new risers so I followed their lead.

Here is a photo of the new ones, with a totally new design. No need for the insulation pads and there looks to be a brass drain plug.

So far, so good.

Ah that stinks. Since you have one of the first ST44s hopefully this is not showing us what is to come. Other than no insulation pads and a drain plug, is there anything different in the design such as slope/angle?

 

[rclarke246]

Probably not a drain plug as it situated near the top. Maybe a port to measure pressure? Angles look the same.

 

[boater3]

Probably not a drain plug as it situated near the top. Maybe a port to measure pressure? Angles look the same.

Oh I think mine do have a sensor there.

Were you able to get any reason/specifics on why they think this will solve the water intrusion problem? I still don't understand after reading all of your posts over the whole ordeal how water is making its way into the turbo. I have asked several volvo techs whether my turbos should be inspected and they all say its not possible for water to go backwards and get into the turbo thus its not worth it to inspect the turbo unless there is an issue.

 

[DavidM]

Oh I think mine do have a sensor there.

Were you able to get any reason/specifics on why they think this will solve the water intrusion problem? I still don't understand after reading all of your posts over the whole ordeal how water is making its way into the turbo. I have asked several volvo techs whether my turbos should be inspected and they all say its not possible for water to go backwards and get into the turbo thus its not worth it to inspect the turbo unless there is an issue.

"not possible for water to go backwards and get into the turbo..."


Spend a little time on boatdiesel and read about all of the horror stories caused by this.


If water is really backing up into the turbo, and it must be for multiple turbos to fail, then I don't think your new riser will help unless it changes the geometry.


David

 

[MichaelB1969]

Probably not a drain plug as it situated near the top. Maybe a port to measure pressure? Angles look the same.

I have a sensor there.

 

[boater3]

"not possible for water to go backwards and get into the turbo..."


Spend a little time on boatdiesel and read about all of the horror stories caused by this.


If water is really backing up into the turbo, and it must be for multiple turbos to fail, then I don't think your new riser will help unless it changes the geometry.


David

So is the exhaust host directly connected to the turbo? I.e. if water does go in reverse flow, the first thing it touches is the turbo?

 

[rclarke246]

I have a sensor there. View attachment 82242

Really?! Mine is just a plug, no sensor wire. Maybe I'll look into this.
Any idea what this sensor is about?

 

[rclarke246]

I understand that the ports are for a temperature sensor. Local Volvo mechanic came to install these for me but, since the plug configuration didn't match he was unable to install them.

Anyway, I'm hoping that the new design of the risers was initiated because of turbo problems, like mine. So far, so good.