What a mess!

[OBXTucker]

Anyone know the per minute volume of the main AC water pump is?!
I'm sure someone does (I don't), but I can tell you it's a LOT!!!

We were cruising back up the bay early this morning and had just come out of Lynnhaven Inlet when I lost all instruments to the port engine. Ran down to the ER to find water spraying everywhere. The bilges under the centerline battery bank and port engine were both full of water, which was rapidly moving forward into other compartments thru weep holes.

Pretty quickly found the water pump culprit, shut it down and closed off the thru hull, along with all 5 AC units.
Apparently the water spray had arced across the shut down solenoid circuit. Fortunately there's not many electronics on these old Detroits! Got everything dried off and the instruments came back to life. I still haven't gotten a close enough look to see what happened to the pump. It appears that the two stainless bands gave loose and/or the hose burst (both were changed in the last 18 months). Hose is still significantly attached and didn't come all the way off....the engine was way to hot for me to be jump down there and check it out.

Spent the rest of the trip trying to get water out of the bilges. It's funny how easily the water found its way forward, but is slow to come backwards. Of course it doesn't help that I just filled the forward tank and the boat has a slight list forward <sigh>. Sometimes ya' just can't win!

Beautiful day for a cruise though....calm seas and a nice breeze.

Anything else I should have done?

 

[carolinacoast]

Stainless bands aren't what they used to be. Cheap chinese stainless I presume. I noticed yesterday that there is some corrosion on ours (just over 2 years old) as I tightened up the bands after noticing some weeping on one. I'm a little fanatical about AC and had my backup pump plumbed in. So we have 2 strainers (use that feature quite a lot for convenience) and 2 raw water pumps. Gives the option for using valves to get to a backup when there is a failure. Since these are 220 volt pumps, the possibility of a bad ground might eat through the bands faster perhaps. If the engines had any circuit boards like all of the new ones, the day may have been far worse. Sounds like you handled things well!

 

[MikeP]

I agree re quality. A couple of years ago I was doing some touch-up painting in the eng room when I heard a "snap," I looked around and one of the large SS clamps holding the rubber exhaust connector to the 8" collector pipe had just let go. The clamps were not more than a couple of years old at the time and looked fine.

I have also had new bronze plumbing fittings leak (china) leak through the side of the fitting due to porosity in the casting. OTOH, it SEEMS to me like a lot of the Chinese stuff is getting better. Recently I needed some small electronic-size screwdrivers. I found some US made ones at the local hardware store and bought those. THey failed on the first screw. Went back, bought the Chinese ones, and they have been fine.

I think US-made stuff is actually worse quality than the Chinese IF it sells at the same price point. But I guess that shouldn't be a surprise due to labor costs.

 

[rsmith]

I dont think there is enough conductivity in salt water to operate a shutdown selonoid. Any how there should be no power to it until you hit the shutdown button. I would more belive the "fire" was put out from water injestion. Not a good thing.

 

[OBXTucker]

I d a tough time believing the "arc" as well. I didn't actually see it. The admiral was standing watch in the pilot house while I was headed down below. She was watching the engine room camera and said there was a huge spark from that area. It's the only thing electrical in that vicinity, thus my comment. It was wet...and yes, with sea water...but that's the extent of my knowledge. Got everything dried up and it worked fine again.

Mal, while I love the idea of redundant systems, I'm not a fan of them when it comes to thru hulls, valves and fittings. In my opinion, just one more opportunity for catastrophic failure and added maintenance/replacement. Hope all is well! Haven't talked to you since after Owners School last year...

 

[Pascal]

Glad you caught it in time! I wonder if failed clamped are the cause of the failure since it s usually very hard to pull hoses off barbed fittings.

Are you sure you dont have some brass fittings in there which may have failed from corrosion? Don't ask hown i know this is the most likely scenario

 

[OBXTucker]

Very well could be a brass fitting (or two). The water was spraying out from the underside of the pump intake and richoceting in all directions. One of the bands was on the bilge floor, but like I said, hose was still attached.

 

[bobk]

A brass fitting that is getting ready to fail usually shows some green corrosion before the leak gets serious. It can be a one to two year process. If you rap it with a hammer it will likely break because there will be extensive degradation. A porous bronze fitting I should think would start to leak almost immediately and very quickly show the green salts. This ought to be no more brittle than a new fitting.

Bobk

 

[Genesis]

"Stainless" band clamps made with inferior (Chinese) material have a habit of failing right under the worm screw from crevice corrosion -- not only is that where it corrodes but of course that's where the clamp is weaker because there's less material there too.

These clamps have always been prone to this failure but it's gotten a lot worse in the last 10 years or so with the Chinese material invasion.... glad you caught it before things got "real"!

 

[Pascal]

It's a good reminder to make sure you don't have any brass fittings in your AC system. The main suspects are male / male nipples which are very hard to find in bronze.

On my boat the strainer was attached to a 90 deg bronze elbow off the seacock, using a brass nipple. I replaced it with Marelon fittings and a short piece of hose after it broke.

 

[dastahl]

I lost the impellor on my favorite Gen set (Way too shallow, mud from Tilghman on the Chesapeake, I should have shut it down). As is always the case with my new-old LRC I noticed other problems including two Bronze or Brass fittings which looked suspictious. I took them out to clean out fin parts and they were fine, but I have them on my list to replace with the good plastic kind.

So, How can I tell which fittings are bronze and which brass? I guess if they are bronze I can keep them as they were solid?

Skooch
58 LRC

Those curious as to what else I found on one simple impellor replaceemnt:
The thru hull had been checked but the strainers was frozen into the housing and was out of line. The top did not fit right so the PO had put silcone on the lid and a oil type gasket which was trying to fail. And the hose was good at the thru hull but as I followed it up to the gen set it was spliced twice and all clamps where too large and most likkely cheap crappy ones. I replaced the hose with one peace and routed it properly with hold down clamps. I even used thru hull approved hose instead of clear water hose. We made it back home after 10 days on the Bay. 58 LRC one step at a time.

 

[jim rosenthal]

Jeff, AWAB hose clamps are all stainless and have a 316 stainless helix in them. Worth the investment. Sorry you had trouble.

 

[OBXTucker]

All part of the learning curve! I guess in retrospect that I'm glad the instruments went down. Otherwise, it may have been an hour or so before I went down to check on the engines.

 

[OBXTucker]

Are you sure you dont have some brass fittings in there which may have failed from corrosion? Don't ask hown i know this is the most likely scenario

Bingo! Nice diagnosis Pascal! Two of them were indeed corroded thru. Now replaced and all is well. Thanks for the recommendation!