Broken Yanmars

[Dirk Diggler]

I've been reliably informed that a number (rather a lot infact) of Yanmars have broken this year. The majority of them in Ribs.

It seems that they have a tendency to rip the port ( I think ) engine mount off the block. The importer of the engines say that if you have been "jumping waves" you will have invalidated the warranty, and so you are faced with a huge bill for a replacement engine.

Does anyone have any experience or knowledge of this.

[Garygee]

Think a e-mail to Barrus is on its way as I have a Yanmar on order.

I think if they ar likley to break "jumping waves" I dont see this as any different as pusing into a steep sea when like it or not your going to have a few hard landings.

I will advise the outcome of the e-mail

Regards Gary

[Dirk Diggler]

You ought to ask about the 10 metre scorpion that broke one, ripped the side out of the block and filled the bilge with oil, ALLEGEDLY.

[MarkWildey]

An answer, although not a 100% answer, is to fit an engine brace and/or fit heavy-duty engine mounts.

There are a number of people who make these and I would recommend anyone thinking of fitting any inboard diesel to spend the extra now and fit a brace and possibly upgraded mounts.

On the other hand if a 10m Scorpion broke a mount then it was likely that a brace was fitted anyway !

Regards

Mark

[Mike Garside]

Originally posted by MarkWildey
An answer, although not a 100% answer, is to fit an engine brace and/or fit heavy-duty engine mounts.

You can see those bits in this pic of the Yanmar 300 retro fitted to my Ribtec. The brace and heavy duty mounts are in place. It remains to be seen whether or not both are tough enough...

[crazyhorse]

I think I will fit these to My Kad or get something fabricated/sorted out.

I dont want to find the engine mounts fail at a later date

[Brian]

I believe that there are only 4 Twin engined, 10m Scorpions. Mr. Byrnes, Mr. Deacons, Mr. Stricklands and a non-Yanmar engined boat.
If any of these had broken an engine mount I would be surprised. If none of them have, will you withdraw your allegation-for that is what it is?

[crazyhorse]

I am keen on freedom of speech,

Especially when it comes down to people wanting imformation about what boat/engines that are good or bad .

I see no reason why that Question can not be Asked.The Problem is I already know the answer. I see it as the same as asking a turkey what it wants to eat for Christmas,it ain going to say Turkey,now is it?

We will see,There are now going to be alternatives to Hard nose Leisure ribs boats and it will be a interesting time,no more you can have any engine as long as its Yanmars?.Gone are the days of the client only getting a small choice.

Its a Free For all and its comeing,Yipee

[Dirk Diggler]

Bad news I'm afraid, it's now fact. I've probed a bit more and have further imformation on the Yanmar problem, so sit back, read, digest and be afraid, very very afraid.

The 10 metre scorpion that broke a motor was indeed Mr Chris Stricklands, he was using the same brace as the one on Mike G's boat.

Prior to that one, a high performance rib, i'm told that is owned by the son of the lady who runs Merlin Boat Park also suffered the same problem. He was also using a Barrus supplied brace.

The Barrus brace was designed to replace the one normally used by Scorpion. It seems it is not up to the job. What a wonderful thing the internet is.

These two ribs now use a brace designed by the builder of the High Perf boat mentioned above. They are not cheap but quality does cost.

It now appears that Yanmar have now redesigned theirs, ( mk 3 version) and this will be standard fitment on all new motors.

Regards,

That useless no nothing fool

Dirk

PS, how about a little praise for using the forum as it was intended, to pass on useful imformation.

[crazyhorse]

Well done Dirk.
now that was good hot off the press news.

Thats what I want to here,Well done old boy,pat on the back and all that.

[Brian]

Well done Dirk.
OK, I apologise for casting nistersions then.
I was suspicious of your accusation initially as I have not been too keen on the tone of some of the comments on this forum recently, and would hate it to be somewhere where people make unfounded accusations.
I am sorry if I doubted you in this instance and well done for broadcasting something that might effect more people (me included!).
Chris, who races, does have something of a reputation for driving his boat really hard. Let us hope that it doesn't happen to too many of us.

[crazyhorse]

Is it not also fair to say that the bravo 3x drive is not a good long term proposition and weather the Bravo 1x drive is any better is uknown at this stage?.

This is what I have heard and that the Bravo 2x is indeed a far more heavy duty drive leg.
Just you get Torque steer if it isnt set up properley as its a single prop.?

Becouse there are so few out thereThe Bravo2 is still a little uknown,

Surley the hull flexing will couse the engine block to crack and the drive iis down to the engine makers.?
Am I wrong here with my maths,and if not why did nobody say something earlier,and stop there friends making the same mistakes,with Drives and engines?

Crazyhorse?

[Brian]

When I first bought my Yanmar and Bravo 3 it was on the advice of Scorpion and their engine/leg supplier.
When I started to have problems I looked round at the alternatives and could not see anything with a better reputation.
That, of course was two years ago.
I have to say, my engine has been faultless-but what is one to do?
Even today. Would anyone recommend a better and more reliable combination or is what we are doing with ribs, just pushing engine/leg technology to it's limits?
If the later is the case then we must live with it or take up growing corn. That's pretty unexciting.

[crazyhorse]

Brian your right,

But lets not fool ourselves Here.

The block will crack if the hull/engine mounts are not designed properley and the stress comes from the hull with its continual twisting of the engine/s,and the leg will go, if the gearing or shafts arnt designed correctley for there intended use.

Thats my take on this,at present?
As you say,We quite rightley make the best decision at the time.
In my case,They already brought out another gearbox that retro fits onto a kad 44.My engine only been out 12 months.?

Crazyhorse

[Garygee]

Hi folks

The Bravo drive saga will I think never be resolved.

Some people swear by them some swear at them.

I was fortunate to spend some time on holiday with a few commercial RIB operators is south wales, a great bunch.

To sum up there comments,

Typical Ribs 9M with Yanmar 300's

Typical use, 12 hours a day, 7 days a week during the summer months.

Bravo 3X multiple failures they dont think this is suitable for commercial work loads
Bravo 1X, never tried
Bravo 2X, now using and to date much better.

However they said they would look for alternatives to the Bravos for future RIB's.

Anyway based on this I have gone Bravo 2 for my new RIB.
While I know is not as quick as the Bravo 3 it does appear to me more reliable.

It would also be interesting if people know if adding showers makes outdrives any more reliable.

Regards Gary

[Dirk Diggler]

is your Yanmar a 4 or 6 cylinder.

[washer]

If you need any info on a good brace to fit `get in touch with DAVE CRAWFORD MARINE.
I have just got my 300 Yanmar from them and they will make the braces for you, and they seem to know what they are on about.
You can contact them on 01590 671251 Fax 01590 678380

[jwalker]

Anyone know of a broken block on a KAD?

JW.

[Mike Garside]

The Bravo 2X that came with my Yanmar 300 was spec'd on the advice of Barus. There is no appreciable torque steer that I am aware of.

Any heel always appears to be the result of water conditions and is easily corrected with a few degrees of opposite side trim tab.

Because I only fitted the new engine right at the end of the summer I have only got 50 hours on the clock. It is probabaly too early to tell whether or not I've got - or am gonna have - the problem we are discussing here.

However, if I do it will be bad news for those of you that have the same engine and like to throw your boat about in the manner of a rallycross 4x4 while driving flat out. I use Magellan Alpha rather more like an old Bedford truck than a Subaru Impreza!

[Alan Priddy]

The sad and sorry story is " There is no such thing as a good gearbox"
I know this from experiance as it has been my day job for 33 years and if they didnt go wrong I would be out of a job!
This simple fact is, a stern drive unit has so many moving parts that it is impossible for them not to break. I undertook a three year test programe with Yamaha to establish why the Hydradrive was failing on certain boats. Our findings where a mixture of bad fitting practices and a problem with the lower gears. Once the gears had been modified Yamaha had very few failures with the exception of certain boat owners who beat the living daylights out of the boat everywhere they went.

I belive that Stern Power in concunction with Mercury make a unit that can take a 1000 hp but this needs a gearbox in front of it and weighs in at a massive 300kgs.

Most boat builders are looking to save space and it is a source of consant amayzment that they try to re-invent the wheel instead of looking at what works.
If I was building another boat I would look at putting the engine in backwards and running a shaft through a "V drive" and rudder. In test's this system gives the longest hours with a 30 foot fast fisher doing over 5000hours without any problems.
Altenativly I would run a jet directly from the flywheel and use the bucket as the gearbox. Of course I would have to fit a bloody big self righting bag to turn it over when it broached in a big following sea and lost drive !

As for the engine mounts breaking on Yanmars all the beefing in the world will not stop this. Again it is a simple case of maths ie.
Downward force over upward force must be equel. If the engine has a heavier G Force at the point of impact with the wave, it is the block that cracks. The Yanmar engine is only a truck based unit and was never designed to take the kind of shocks that are being generated in a boat. the only way round this is to mount the engine in a different way. Again there is a wealth of experiance out there it just isnt being used because the builders of the boat are to proud to ask and rely on the customer to develop the boat. Alternativly, Dont jump waves, If you want to fly buy an aeroplane. Boats float Planes fly. If anyone needs any further information contact me by private mail. Alan P