Engine failures pose a question

[Renegade_Master]

Those of you who have been following Matts progress (great thread too) cannot help but have noticed a couple of occasions of Matt having to make progress and bring the boat in on one engine. Now bare in mind this is not a cheap machine or engines we are talking here.

Only goes to show engine failure can happen to anyone and not only on a long passage like this, though perhaps more likely.

Point is what if he had only got one engine? /forums/images/graemlins/shocked.gif

 

[[2068]]

I don't think I'd try and cross Biscay on one engine, but for buzzing around the Solent, one reliable single seems to work fine for me.

So far...

The old argument "one is good enough for fishing vessels" never cut much ice with me, the fishing industry having one of the highest death-in-service rates around.

dv.

 

[jhr]

I've been pondering this myself, in my usual ill-informed way.

I guess the answer is that, if I had a 70 ft single-engined boat it would be a displacement craft with a simple, no frills, low-revving diesel. It wouldn't be running for long hours at high revs under stress and would just keep going. As proof, I'd cite the recent Atlantic crossing by a group of Nordhavns, almost all of which were single engined (though some had an auxiliary wing engine I think) and none of whom broke down.

When all's said and done (and no disrespect to Matt or his boat) a Leopard is a ruddy great sports powerboat, designed for short, fast blasts rather than epic voyages. I don't imagine her builders had in mind the kind of trip that Matt's just completed, though I find it sobering that he had so many gear failures. However, he has just completed, in the space of a couple of weeks, probably more running hours than I would do in a season so, looked at as a year's worth of breakdowns, perhaps it's not so bad.

 

[Bergman]

Not really my thing as a raggie, but I have wondered a bit too.

Certainly one would expect MAN to make a good quality Diesel, they practically invented the things and lots of MAN engines in all sorts of applications.

Although topical at the moment after TCM's epic trip, there are many posts on here about engine problems of one sort or another, far more than one would expect from a similar sample size of motor cars.

So is it the application, in a sports boat, that is wrong. Accepted wisdom is that Diesel engines work best on a high load that is sustained for long periods such as fishing boats, generators and railway trains. Certainly fishing boats do have a bad safety record but I suspect engine failure is not the major cause of loss of life.

So for "leisure" use would petrol engines be a better choice? less efficient perhaps but would they be more reliable? Leaving out the bit about 1000 gallons of volatile and flammible fuel that is.

I suspect not, not many people would opt for petrol rather than Diesel I'm sure

A casual check on the types of failure seems to point to "top end" sort of issues, camshafts, fuel lines, cooling system sort of areas. Cant find many crankshaft, piston, bearing sort of faults.

Maybe a more scientific analysis would help, there is certainly a good sample on this forum.

Do the manufacturers do any specific research about how big Diesel engines perform in a sports boat environment? perhaps they should.

Does motoring at high speed put excessive loads on parts of the engine, perhaps G forces need to be taken more into account, maybe rapid changes in engine load as boat bounces in and out of water - Dunno.

Dont know the answer but the reliability of marine Diesels used in high performance leisure boats, judging from postings on here, would appear to be significantly worse than similar engines used in other applications.

Considering the price of the things both to buy and to maintain, that should not be the case.

Makes me glad I have those big white flappy things!

 

[Renegade_Master]

"a Leopard is a ruddy great sports powerboat, designed for short, fast blasts rather than epic voyages "

Cant agree there, dont think I would spend that kinda money and restict it to short blasts up the coast, I would want to do similar trips and would be disappointed to think that the builders might not have considered me doing so when charging me so much for the vessel.

Take your point about the Nordhavns though low revving single engine crosses atlantic makes more sense. I think they are great tubs, in fact we got the charter job as photot boat to film them coming into Gib last year.

 

[capnjack]

This is a great Topic and one that I just have to throw my 2 pence worth into.

We all drive cars, right, they're reliable?

There are lot's of lorries and buses out there! They all have diesel engines and are worked to buggery and they're reliable?

Why should a boat engine be any different?

 

[Nautical]

Many sports boat engines are left for long periods without use, probably 25% of their running is under no load tied up to a pontoon which is deadly for a diesel, puts terrible wear on them as they never reach working temp.

My theory is use it or loose it, get em out there and give em a right good thrashing.

Makes me laugh when people talk about getting a fab deal on say a ten year old sports cruiser 'and guess what it only has a few hundred hours on it'. Everything is probably rusted to heck.

People tend to shy away from anything with a 1000 hrs or so yet in a truck that is only one years use and it would still be under warranty!. I would far rather a ten year old boat that had a 1000 hrs plus on it, means its been used regularly.

 

[boatone]

[ QUOTE ]
Many sports boat engines are left for long periods without use, probably 25% of their running is under no load tied up to a pontoon which is deadly for a diesel, puts terrible wear on them as they never reach working temp.

[/ QUOTE ]

If the unreliability was actually associated with this useage pattern I might agree but this would seem to be rarely the case.
Far more often the problems are associated with failure of ancilliaries, electrical or mechanical - witness tcm's recent saga. IMHO the real problems frequently are evidenced to be due to bad spec or inadequate servicing....and look how dangerous the position can become when you lose an engine because of a split olive in the fuel line !

 

[capnjack]

In my thread, the last question I asked was...."Why should a boat engine be different". This has been answered by both Nautical and Boatone.

Engines heat up to a desired temperature in order to operate efficiently. The materials used, in todays world are reasonably advanced, but are not as robust as we think. Furthermore, as fluids flow, seals become more effective, in addition passageways stay open and clear. The more we use them, the more reliable they become, until they perish and need replacing.

The biggest problem with Marine engines is, they do not get used regularly enough.

 

[Deleted User YDKXO]

The real problem is us, the punter. We expect our latest gin palace to do 30knots minimum, to have all the comforts of home installed and to have domestic sized cabins and heads. These are conflicting requirements resulting in engine manufacturers competing with each other to offer ever more powerful engines with ever more compact dimensions and lighter weight. But more power means more heat and higher stresses
Modern turbo diesel engines are far removed from the low revving under stressed luggers of yore which chugged on for decades without complaint. Modern engines are highly tuned performance motors and nobody should expect years of reliability. You only have to look at the power outputs that leisure marine engines put out compared to the same engine in industrial specification. The leisure marine power rating can be twice that of the industrial rating and the reason that engine manufacturers can get away with this is that the typical leisure marine duty is very light, 100hrs pa compared to 2-3000hrs pa for an industrial engine.
So, we should'nt be surprised when leisure marine rated engines give problems when they're subjected to heavier use
Worth reading
Yacht Survey - More on Performance Diesel Engines

 

[Bergman]

Yes I read it.

Interesting although had the feel of a sales pitch. Not sure that his diagnosis of over propping and bad maintenance is the full answer though.

There seem to be sort of two views developing, firstly under use and secondly over stressed by design to meet power/weight/size requirements.

I can see that these could well compound each other.

So is the answer a different type of engine? Would a petrol engine be a solution, its lighter for a given hp than diesel.

But thinking about a motor car, do they not have the same pressures to develop more power for a given size and weight? yet they appear to be much more reliable than the type of boat engine we are discussing.

What sort of bhp/litre are we talking about from a boat engine? I have a Toyota turbo diesel which gives 88bhp from a 2 litre engine - is that about what a boat engine gives - say 12 litre for a 500bhp mill?

 

[whisper]

That Toyota engine is giving 44bhp per litre. In comparison a KAD 43 puts out 79bhp per litre - if my dodgy maths are correct.

 

[bdsweeting]

Mind you, all engine problems are relative I think...

This afternoon a vessel called into the CG to report the fact that they would be stopped outside the TSS off Casquets to stop the engine and change some injectors!

Not something I would fancy in a bl**dy great ship, but all in a days work for some it seems.

 

[Nautical]

A factor I am sure but I still hold to my original statement, lack of use and lying around for months on end and then only run to charge up the batteries plays havoc with a diesel engine. Seals become hardened, oil drains away from all the trickery bits, rust begins to appear and before you know it the darn thing breaks down.

Basiclly all marine engines are just truck engines marinised no matter what the manufacturer tells you, maybe a slight tweak to the engine management but basically the same lump. Even the Volvo D3 is straight out of the XC90 D5 4x4 and is nearly identical in power and torque, if one of those broke down on the school run after 12 months you'd be peed off, but cars/trucks are run everyday, get to working temp quickly and are aways under load.

My motto, as before, thrash the life out of it as much as possible and it will keep going, leave it lying around and it will be a pig.

 

[Renegade_Master]

Agree entirely they need to be used & serviced often. I too when buying would be troubled by a 4 year old boat with 200hrs.

A case in point which supports both of the about. My boat is 1999. When I bought her in 2003 she had 1400hrs, (used for charter & school) but had been serviced. Two KAMD43's. She has now done a further 1000 plus hours in two years being used at least 4 days a week in the summer season, serviced every 100 hrs, and shes fine. Yes I've had probs, belt tensioners for one, and an injectors pump, which I'm told is very rare, oh and water pumps.

We all seem to have digressed from my original point however, and that is given the recent probs tcm had should we not be thankfull for twin engined boats.

Even thought we know they are unreliable, at least you have a second one to get you home.

 

[[2068]]

"Basiclly all marine engines are just truck engines marinised no matter what the manufacturer tells you"

No they're not. Some of the bigger stuff (e.g. D9 / D12) might be, and the D3 is the same as in a Volvo S60, but you won't find the KAD32, 42, 43, 44, or 300 in any truck that I know of.

dv.

 

[capnjack]

Here are some more brain teasers, if Caterpillar can build a truck engine that is not an old slugger and that has all the latest technology, producing up to 600hp and which has won the JD Power customer satisfaction survey 4 yrs running, why then do marine engines suffer?

In as much as I agree with Deleted User's observations, I think the above example shows that Marine engines are not unique. I see Nautical and Sun-Coast are mirroring my thoughts too. Trucks are used more than most vehicles, in fact daily generally and for a diesel engine to be reliable it should be run up to temperature regularly. In fact diesel generators used in very cold countries and only running at idle, rarely reach correct running temperatures and therefore are prone to breakdowns. So what is the answer? Well in my opinion, engines should be run daily and to working temperatures, thats fine, but how many of us get the time to do this?

Any thoughts?

 

[boatone]

[ QUOTE ]
diesel generators used in very cold countries and only running at idle, rarely reach correct running temperatures and therefore are prone to breakdowns.

[/ QUOTE ]
Sorry to harp on about this but what sort of breakdowns are they prone to???
As i said in my earlier post here, my perception is that most of the breakdown stories we hear re marine diesels relate to unreliability/bad servicing etc of ancilliaries rather than a failure of the engine itself.
Might be useful to have a poll of various breakdown scenarios vis a vis failure due to water pumps, fuel pumps, electrics, drive belts, fuel pipes etc etc...
I've a sneaking suspicion we may find true 'engine failure' quite a rare event.

 

[Nautical]

Yes they are not Volvo truck engines in the case of KAD series but I bet your bottom dollar they originate from a truck source. For a manufacturer to develop a purely marine diesel is un-economical.The millions it take to develop a brand new engine would never be re-couped in the marine leisure business, the unit sales are just to small.Only when you get to the seriously massive stuff like tanker engines are they made purely for the marine industry and even some of those are from power generation plants.

 

[[2068]]

Wrong: the AD40/41, the AD30/31 and all their derivatives were built purely as marine engines. There was no 2.4L or 3.6L truck block that they were based on, or ever used, in, that I'm aware of. If u can point to information that suggests otherwise, I'm happy to be corrected.

As you say, this doesn't make sense economically, and the latest generation has moved towards block sharing in a big way, but the KAD3x and KAD4x series were only ever meant to be marine engines.

Anyway, grumpy mode off, the fog has cleared (a bit): time to go boating !!!

dv.