Twins overheating at the same time- the great mystery resolved...

[David Hughes]

So the family and I were on our Leopard 37 Powercat , just leaving Shark River in the Everglades, on a trip to The Keys. Three miles offshore the overheat alarm goes off on the starboard motor. I immediately turn it off and continue on the port motor as I think about things. Not 30 seconds later the overheat alarm goes off on the port engine too.....I shut it down too. Hmmm ........

I can see, hear, nor smell anything wrong, and bilges are clean, coolant is full, strainers clean, water flow is fine, etc. After a rest, I start them up again and resume. Not 3 minutes later both alarms go off again within 30 seconds of each other. I wait again and try at very slow speed, whereby I get an extra 3 minutes before alarms.

So the riddle is what can cause both engines to fail at the same time? Could I have destroyed both impellers or sucked up plastic bags into the intakes? Sure didn't think so.

Well now we were adrift and at least 30 miles from cell phone service so I can't call anyone for advice. I try calling TowBoatUS on the VHF. Nothing. By the way, we have not seen another boat of any kind for 18 hours. This is the off season and we were way down on the southwest tip of Florida. Now I try calling anybody at all. Anybody. Nothing. After an hour, finally Coast Guard Sector Miami hears me and responds. They ask about imminent danger, medical conditions, ages of the children, etc, and I tell them we are fine, but need a relay to TowBoat. They do that, after getting CGSector Key West to listen in and take over. TowBoat drives 50 miles in 2 hours and pulls alongside. Now I should mention that low battery lights come on at the AC panel and I see that the house batteries are pretty low. Hmmmm again. Oh did I mention that also the RPM gauges on the helm stopped working? Important points in hindsight.

Things add up to something electrical, right? Long story short, turns out bolt V belts were found broken. These motors are electrically connected so that both batteries may be charged by running only one engine. So in the event one alternator fails, the other can take over. Here's the design flaw: if one v belt is gone, or one alternator failed, there is no warning system of any kind. You only know you have a problem when the other side fails.....

Live and learn!


David Hughes
2009 Leopard 37 Powercat for charter in Cape Coral, FL
Florida Catamaran Charter the "True Love"

 

[FF]

Here's the design flaw: if one v belt is gone,

Warning system ,

EYEBALL Mark 1 Mod 0

 

[David Hughes]

Agreed, but the belts are at the very inaccessible front of the motors, and behind covers so not visible without removing the covers. That, and I'm no mechanic.... : )

 

[Capt.Bill11]

First thing do is remove those covers for good. Then you could add volt meters or indicator lights that read directly off each alternator.

 

[jleonard]

First thing do is remove those covers for good. .

Yes! Remove those covers. Or modify them with clear plastic panels so you can see inside.

 

[TG]

Good candidate for engine room cameras.

 

[sunchaser]

Pardon me, but I'm going to nag. For starters, what are the engines and at what RPM are they normally cruised.

There are many things to go wrong on a boat. Power cats with virtually inaccessible engines add to the list of potential woes. Top it off with an owner who is "no mechanic" and stranded off shore during storm season provides the makings of a less than happy ending.

Some good suggestions have been offered up. The list though of things to be aware of is long. The engine maker has produced a list of things to service and check. For sure V belt servicing is on the list. In general, given the inaccessibility of the engines, the engine's to do and check list should be adhered to with a vengeance.

If I read this correctly the vessel is used for charter. I'd guess there is a very long list of operating and maintenance instructions. What does it say about engine checks in particular V belts?

Again sorry to nag,

 

[smitty477]

Looks like Yanmar 110's - all good questions above. Current hours on engines would certainly be an interesting fact.

 

[Capt.Bill11]

sunchaser brings up a good point. And it appears you are paying a management company to take care of your boat. If they are not checking the belts because they can't be bothered to take off the covers, what else aren't they checking?

Imagine if that had happened to a charterer that has no more mechanical ability than you. And had his family aboard. Refund time.

I'd have a word with them about the maintenance schedule. And remind them that their check out/check in captain/s should be looking for those kind of things.

 

[bayview]

How in the world would both belts break at the same time????????????

 

[sunchaser]

How in the world would both belts break at the same time????????????

Maybe one belt had been broken for quite some time? Failure of remaining belt triggered a good look at both sides.

 

[hmason]

How in the world would both belts break at the same time????????????

Bilge ferrets.

 

[Ski in NC]

If that is a Yanmar 4JH, good chance the engines cooked pretty badly with belts off. Temp sensor is not directly on cyl head so it takes a long time for heat to soak to sensor once belt breaks.

See if paint is "browned" on cylinder head.

Yanmar V-belts have been a weak spot on several of their models. They like to eat belts.

 

[Xsbank]

"Yanmar V-belts have been a weak spot on several of their models. They like to eat belts."

Remind me to choose a Yanmar for my next marine engine. How impressive.

Or maybe a VW...

 

[dwhatty]

Bilge ferrets.

Yup. Bad news. Almost as bad as polyester mites.

 

[David Hughes]

Ok all. Here's more info: motors are Yanmar 110's with 2600 hours on them. And as someone wrote, they are very difficult to access. Yanmar guy who fixed them was certain those covers had NEVER been off. He also agreed it's best to just leave them off. Service manual says change V belts every 1000 hours. Another black mark on The Moorings for their poor preventive maintenance.

Don't think they got too hot. Paint isn't discolored. They were checked pretty thoroughly by the Yanmar tech and they also ran just fine all day today taking the boat back to home port.

The stock Yanmar instruments don't have gauges for temp, or oil pressure, or battery; just warning lights and alarms. I'd like to install actual gauges so I could monitor myself.

Thanks for the input everyone.

 

[sunchaser]

Mr Hughes

Thanks for sharing and glad it all worked out. Good to see you got right in it.

 

[Ski in NC]

If engine did not blow out it's coolant, it probably did not get too hot. If hot enough to damage engine, steam forms in coolant jackets and blows it out all over engine room and into bilge. If only a little lost, probably ok.

And yes, sh!tcan belt guards if it makes it hard to access belts. Only keep them if they are truly improving safety, like front of engine is open to contact you if in engine room.

 

[Capt.Bill11]

Bilge ferrets.

That is exactly why I prefer bilge weasels.

 

[N4712]

That is exactly why I prefer bilge weasels.

I must ask what do bilge weasels do?

 

[Capt.Bill11]

Maybe one belt had been broken for quite some time? Failure of remaining belt triggered a good look at both sides.

But if the belt on one engine had been broken for quite some before this incident the engine with the broken belt would have over heated a quite some time ago.

 

[Capt.Bill11]

The stock Yanmar instruments don't have gauges for temp, or oil pressure, or battery; just warning lights and alarms. I'd like to install actual gauges so I could monitor myself.

No gauges at all!? The boats builder should have known better. Talk about taking the cheap route.

Yeah, get some gauges ASAP.

 

[FF]

I'd like to install actual gauges so I could monitor myself.

Only takes a bit longer to install real mechanical gauges.

When running your engine needs no electric , why should the gauges not be similat?

The Murphy switch gauge cost little more , and can ring a bell when the reading varies from your preset.

Better than a hired engineer , as they never sleep on the job.

 

[LarryM]

No gauges at all!? The boats builder should have known better. Talk about taking the cheap route.

Yeah, get some gauges ASAP.

Yanmar definitely makes gauge panels for all of their engines. There are several levels of instrumentation available, from a simple tach with lights, to full instrument panels with VDO instruments and senders. There are also engine-specific third-party panels available from firms like Mack Boring.

What the builder chose for instrumentation is all about economics.

Here is an example of a factory C-series twin-engine panel. While not inexpensive, it would have been available to the builder when they specified Yanmar power.

 

[sunchaser]

What good would gauges do if preventative maintenance is not performed per book? On belt driven water pumps some slippage may occur before failure, triggering a Murphy gauge as FF suggests, or the Yanmar alarm as occurred.

The owner did catch the belt failure via the alarms. With only a gauge and no alarm maybe engine failure would have occurred

I can certainly see where a temperature gauge will creep up as HX fouls, but a belt failure leading to a water pump shutdown, I don't know. Love those gear driven pumps where only the alternator stops if a belt fails.

 

[Capt.Bill11]

What good would gauges do if preventative maintenance is not performed per book? On belt driven water pumps some slippage may occur before failure, triggering a Murphy gauge as FF suggests, or the Yanmar alarm as occurred.

The owner did catch the belt failure via the alarms. With only a gauge and no alarm maybe engine failure would have occurred

I can certainly see where a temperature gauge will creep up as HX fouls, but a belt failure leading to a water pump shutdown, I don't know. Love those gear driven pumps where only the alternator stops if a belt fails.

Obviously nobody is saying you should only have gauges with no alarms. But as you pointed out, with gauges at least you have a chance of seeing the temps rising before you reach the alarm point. Even in the case of the belt failing.

 

[Capt.Bill11]

When running your engine needs no electric , why should the gauges not be similat?

I don't believe that is true anymore with many/most modern diesel engines.

Not to say that mechanical gauges aren't a better option than electric ones.

 

[bayview]

If the boat is still in charter service gauges wont be as helpful as a loud alarm

 

[jb cruzan]

How in the world would both belts break at the same time????????????

Shrapnel from the first belt jettisons the 2nd.

 

[MurrayM]

Just a personal observation...our 4JH2 doesn't eat cogged V belts like it used to chew through regular smooth V belts.