Muffler failure and related sinking

[Steve Mannshardt]

Hi all,
Interesting problem on a neighboring Post 46 this weekend. Boat is a total boys battle wagon. These boys are so committed to this boat that their wife's have no fears of another woman. It's all about the boat and raising fish. So, she's been on the hard for the past 6 months for an amazing refit. Primarily systems. Boat at launch time was the stone boss. The intent was to spent 3 weeks doing sea and systems trials and the up to Bodega Bay for some fishing. Nee and I were on the boat Friday night and all was well. Sunday I get a picture texted to me in her slip sunk to the fly bridge. Today was spent getting her raised and into a travel lift. The boat is 485 hp powdered 6-71TI's. Upon start up on Sunday there was a loud bang from the Port engine. All was shut down and 3 mins later she was headed fast to the bottom. Today we found the port side fiberglass muffler had one side completely blown out. The cause of flooding was obvious. The question is what what would cause a failure of this kind? Catastrophic failure of a muffler due to pressurization is the assumption. The first guess is vermin or birds nesting in the exhaust. But that said one would assume the engine would simply die due to exhaust restriction. I'd be real interested to hear if anyone is familiar with this as I know I have fiberglass mufflers in my 53 YF.

 

[captddis]

It happens once and a while but mostly on gas powered boats and mostly aqua lift mufflers.
I am suprised that they could not stuff a pillow or something into the exhaust pipe.

 

[jim rosenthal]

Had the boat been run before, after the long time out of the water? It does sound like something blocked exit of the water and gas from that exhaust? The gas might not do that by itself, but with the pressure of the water, it might very well.

I've seen people use foam plugs or balls to stop up the exhaust outlets when boats are hauled. Maybe not such a bad idea, as long as you remember to take them out when she goes back in.

 

[Steve Mannshardt]

Ya. I hear both of you. We all agree a gas boat will be more prone to this than diesel. And, there has been discussion about muskrat or other vermin. Boat was splashed last Wednesday. Sat in the slings for a day and engines run. Then moved to a slip less than 500' feet away. Boat ran fine. Very odd. I know I'm going to have a grate glasses into my exhaust to keep potential critters out.
She's a sad sigh tonight with oil dripping off the headliner onto the cabin sole...

 

[Sailor John]

Interesting!
Same thing happened at our Club to a (very nice) Egg Harbour.
When the skipper started the boat, the starboard engine backfired and (unbeknownst to the skipper) blew the muffler pipe right off at the exit. It started to sink right away, although some time passed before the skipper noticed and panicked appropriately.

Interesting to note that, being unable to stem the flow of water, they called the local fire dept. just across the bay to assist with water pumps. The FD declined to assist, citing the fact that they 'didn't do that'. When someone suggested they would have a much tougher time cleaning up 500 gallons of diesel fuel out of the harbour, they arrived soon enough and put several large pumps on board and saved the boat. It was then towed and hauled out for repair.
I thought it was one in a million.
Guess not!
Sailor John

 

[GaryNW]

Havn't been here in a while. Sort of interested. I have 5" vernalifts with new 496 Crusaders. Replaced high hour 454 Marine Power with 4" vernalifts. All is well at 300 hrs, yet I have heard don't use vernalifts with gasers. When can I expect what has worked for 20 years will suddenly sink my boat? If my input is garbeled, it is because my cat is literally sitting on my mouse.
Gary



























i

 

[GJH]

The specific issue in this thread aside, it is a good idea to check the integrity of your exhaust system with some regularity. Such as the tube on the muffler where the exhaust hose attachs :

 

[chuckbullett@gmail.com]

The specific issue in this thread aside, it is a good idea to check the integrity of your exhaust system with some regularity. Such as the tube on the muffler where the exhaust hose attachs :

You're all freaking me out a bit.

We just replaced the SS Y-Collectors on both 8V-71Ti's with custom high temp resin fiberglass Y-collectors and high-temperature hoses.

We had only used single T-Clamps on each connection and our surveyor popped by yesterday and stated that he'd be more comfortable with two clamps on each side of each connection, even with the T-Clamps... so based on these comments I am thinking that, that is what we'll do.

What was the name of the Bodega Bay YF that sunk? We're in the SF Bay area... and I would like to find out more of what they did or didn't do in the re-fit prior to splashing ours in the next two weeks for obvious reasons.

Many Thanks for posting-

Chuck- 53MY "Chartmaker"

 

[GJH]

Chuck, I have been spending a lot of time the past year in Bodega Bay tending to a family matter. Have not seen or heard of a YF there, let alone sinking, and we like to bum around the marinas now and then. I'll ask around when I am back there next month.

When we replaced our tubes, which involved sawing them off the muffler, we installed new tubes and enforced them with "crush rings" we got from Hatteras, actually. Required very $pecial high temp epoxy. Then double T clamped, but not too tight. Used a high temp Permatex product to provide further seal twixt tube and hose.

 

[Steve Mannshardt]

Boat is named Black Cloud. Failure was at the yard dock in Stockton. Bodega is a favorite spot of the owners but I don't believe she'd be considered a local boat.
The cause remains a mystery however there are a few valid theories. The most common replayed to the number of people that were in the cockpit. Upward of a dozen or more. The theory was the muffler itself was completely flooded with water with the exhaust underwater. A possible weak spot in the muffler combined with the hydraulic pressurization of the complete muffler led to the failure. The failure is remarkable as there is a large portion blown out and resulting shrapnel in the bilge. It went with a bang.

 

[chuckbullett@gmail.com]

Well, at least she was appropriately named.

George- Thanks for the heads up on the crush ring. We've already assembled both systems this week but I'll check the T-Clamp bolts for excessive pressure or tightness.

@ Steve- Thanks for the info.

Including a photo of one of the new y-collector fittings... been working on this since we hauled in mid-May.

Hope everyone has a safe long weekend-

Chuck B; mv Chartmaker and sv The Chester P[/I]

 

[springhill]

With technology and cell phones getting so cheap, i'm surprised there isn't an alarm of some sort that calls you when the water level gets beyond a certain point.

 

[Steve Mannshardt]

The way this boat went you'd be pulling your phone out of your pocket to answer the app as your feet were already getting wet.