480 DB Owners Club

[rlynch03]

I had my entire system from the muffler to the turbo replaced and did it in the water; nary a drip....

you replaced the Turbo's?

 

[ttmott]

you replaced the Turbo's?

I had them checked; other than cleaning and painting they were good to go. I did, however round-file the turbo insulation and replaced with blankets.

 

[rlynch03]

I had them checked; other than cleaning and painting they were good to go. I did, however round-file the turbo insulation and replaced with blankets.
View attachment 95367

Is there a company that tests/checks the Turbos? I have a leak around mine. Leaking exhaust back towards the fresh air side. I hope it is the connections rather than the body or an internal issue.

 

[ttmott]

Is there a company that tests/checks the Turbos? I have a leak around mine. Leaking exhaust back towards the fresh air side. I hope it is the connections rather than the body or an internal issue.

Yea, somewhere here in Fl. My mechanic sent them there.

 

[quality time]

On the 480DB, we have about a 5' long soft hose connecting the muffler to the exhaust port. There is water about half way up this hose when fully loaded so you could definitely take on water if they chewed a hole in the first few feet.

 

[WDR]

This is a typical DA / DB exhaust and specifically for the QSM-11. It's typical for above water exhaust with mufflers. Except for the entry into the hull which is hard fiberglass all of these components are above the waterline. The little buggers must have chewed through the fiberglass. All hull penetrations which have hose below the waterline have thru-hull valves. Those boats with underwater exhaust have a fiberglass riser above the hull penetration that connects the hoses above the waterline.
View attachment 95362

Part #1-#4 look nothing like that on my 2004 480DB w/ QSM11s. Let it come loose anywhere below the riser w/out keeping it suspended high enough, and you risk getting a back flow that will sink your boat.

 

[quality time]

480DB exhaust set up

 

[ttmott]

Part #1-#4 look nothing like that on my 2004 480DB w/ QSM11s. Let it come loose anywhere below the riser w/out keeping it suspended high enough, and you risk getting a back flow that will sink your boat.

Are you sure? So the fatal flaw is you loose cooling water and burn through a hose then the boat sinks.... My 400DA and 52DB as well as my dock neighbor's 450DA are all well above the water for all of the exhaust hoses. I'll get some photos on the 52's arrangement at the hull penetration.
So the 480DB (predecessor to the 52) does not have mufflers?

 

[quality time]

See pic above Tom.

I've had the stainless tubes (#6) off while in the water and nothing came in. It was however just at the inlet of the muffler about where it passes through the bulkhead in the pic.

 

[WDR]

View attachment 95376

480DB exhaust set up

That’s what mine looks like. I know the Cummins mechanic tied it up (suspended) w/ a bucket taped in it (at #7) when turbo was removed. My understanding is there is supposed to be a “flapper” (non-backflow) mechanism in the barrel part of the system, but that it is not fail safe (I don’t know much about that either way). Also I was told the reason it is suspended in the air w/ bucket inserted was that If a few sizeable waves/wakes rocked the boat, or something otherwise tilted the boat (there were a couple of surveyors and mechanics getting on and off the boat), that the disconnected pipe would be partially below the waterline and if a back flow started it would sink the boat. They said it would come in so fast you wouldn’t have time to do anything about it. Maybe not Much of a risk, I don’t know, just know what I saw and what they did. I personally wouldn’t take anything loose from that barrel muffler while sitting in the water. Interesting discussion for sure.

 

[ttmott]

This is the 52DB; the hull penetration should be just about the same as the 480... The red line in the second picture is the water level and that first hose is item 3 in the previous picture of the exhaust system; it's close and I'd never leave it open but the rubber parts are above the water line.

 

[SeadawgVB]

So I just finished reading through the entire thread for the second time, taking notes and copying the links of the pages I may need in the future. My potential future boat is being hauled out today to have the blister/delam issues mitigated on the current owners dime. We have a signed "conditional acceptance" that allows us to walk if once the blisters are opened up, and we find that it it is much worse than anticipated (i.e. spreading throughout the coring).

More will be revealed as they saying goes.

My concern is now that I may actually wind up with this 480, what keeps me up at night? Aftercoolers.

I always prioritize the issues according to what kills the engines the easiest / first and then try to mitigate that risk.
I plan on setting up freshwater rinsing according to Tony Athens' recommendation. I also think I read something on boatdeisel about monitoring air pressures before and after the aftercooler in order to see how much accumulation of 'stuff' is in the cooler core.

Anybody do or know anything about the differential air pressure thing and how to set it up?

So once they open the blisters up and it seems as if the is no creeping rot in the hull, I will pay to have the props pulled and have an inch of pitch removed from them...... Let's see what happens next.

 

[ttmott]

So I just finished reading through the entire thread for the second time, taking notes and copying the links of the pages I may need in the future. My potential future boat is being hauled out today to have the blister/delam issues mitigated on the current owners dime. We have a signed "conditional acceptance" that allows us to walk if once the blisters are opened up, and we find that it it is much worse than anticipated (i.e. spreading throughout the coring).

More will be revealed as they saying goes.

My concern is now that I may actually wind up with this 480, what keeps me up at night? Aftercoolers.

I always prioritize the issues according to what kills the engines the easiest / first and then try to mitigate that risk.
I plan on setting up freshwater rinsing according to Tony Athens' recommendation. I also think I read something on boatdeisel about monitoring air pressures before and after the aftercooler in order to see how much accumulation of 'stuff' is in the cooler core.

Anybody do or know anything about the differential air pressure thing and how to set it up?

So once they open the blisters up and it seems as if the is no creeping rot in the hull, I will pay to have the props pulled and have an inch of pitch removed from them...... Let's see what happens next.

QSM11's rarely have aftercooler issues; They need their scheduled maintenance and that's it.
Monitoring charge pressure? No.
Fresh water rinse? I have it and don't use it but, however, the boat gets used a lot.

What should keep you up at night?
An over prop'd boat as that is what raises havoc with the exhaust system.
A gear cooler that hasn't had the Cummins required support modification done; that failure will sink the boat.
Making sure all of the metallic components are correctly bonded and bonded to the hull zinc. Especially, if those metal exhaust tubes after the risers are not bonded pin-holes are sure to appear.
Below the waterline hoses.....
The anchor swivel link.

 

[quality time]

Not sure I can add much more than Tom already has but I agree, no aftercooler issues as long as you maintain them every 4-5 years.

Best to plan for a service soon if there is no record.

 

[SeadawgVB]

QSM11's rarely have aftercooler issues; They need their scheduled maintenance and that's it.
Monitoring charge pressure? No.
Fresh water rinse? I have it and don't use it but, however, the boat gets used a lot.

What should keep you up at night?
An over prop'd boat as that is what raises havoc with the exhaust system.
A gear cooler that hasn't had the Cummins required support modification done; that failure will sink the boat.
Making sure all of the metallic components are correctly bonded and bonded to the hull zinc. Especially, if those metal exhaust tubes after the risers are not bonded pin-holes are sure to appear.
Below the waterline hoses.....
The anchor swivel link.

I will re-pitch the current props if the hull repairs aren't too hairy. The gear coolers have the mods done. I'll look at the bonding on the exhaust - good tip!

 

[SeadawgVB]

Not sure I can add much more than Tom already has but I agree, no aftercooler issues as long as you maintain them every 4-5 years.

Best to plan for a service soon if there is no record.

Engine surveyor told me that Cummins now recommends the seawater side flushed annually (done this March) and not to tear them down for inspection until x years (I forgot). I get the fact that these aftercoolers are not the copper and aluminum 'batteries' that are on the QSBs and QSCs (The Ms have the stainless cores). What is the actual maintenance regimen on these QSM aftercoolers?

 

[quality time]

I'm not sure what the actual spec is but I have mine torn down at 5 years. I'm in brackish water up the bay from you.

 

[cod]

Engine surveyor told me that Cummins now recommends the seawater side flushed annually (done this March) and not to tear them down for inspection until x years (I forgot). I get the fact that these aftercoolers are not the copper and aluminum 'batteries' that are on the QSBs and QSCs (The Ms have the stainless cores). What is the actual maintenance regimen on these QSM aftercoolers?

I honestly don’t know what a freshwater flush will do if it’s not done after each use. Take it a step further and flush with Barnacle Buster. I set up a 5 gallon bucket with a pump and cycle fresh water and then add the Barnacle Buster. You’ll see the clean blue water turn to baby s#$& brown.

 

[rlynch03]

I honestly don’t know what a freshwater flush will do if it’s not done after each use. Take it a step further and flush with Barnacle Buster. I set up a 5 gallon bucket with a pump and cycle fresh water and then add the Barnacle Buster. You’ll see the clean blue water turn to baby s#$& brown.

How often do you flush the Mains with Barnacle Buster?

 

[rlynch03]

I will re-pitch the current props if the hull repairs aren't too hairy. The gear coolers have the mods done. I'll look at the bonding on the exhaust - good tip!

I would recommend to get some seat time and document the RPM, Speed and GPH with 3/4 to Full weight with gas and gear before cutting the props. Several of us have trimmed more than an 1" and still are not at the desired GPH at 2000rpm's.