Turbos

[Way]

Is the idea that sail boat engines shouldn't have turbos a thing of the past? would've thought that Yanmar and Volvo wouldn't get something so significant 'wrong'?

 

[Bobc]

Volvo have been supplying turbo engines for over 20 years.

 

[sailorman]

Its a power / weight ratio +emissions.
i would not have 1 in a yacht

 

[Way]

Is that because you prefer the simplicity of a non-turbo? or RPM considerations?

Its a power / weight ratio +emissions.
i would not have 1 in a yacht

 

[PCUK]

Turbo-charged engines run more efficiently and are more economical with less emissions.

 

[pvb]

With a small engine, there's no real need for the added cost and complication of a turbo. Volvo Penta only added a turbo to the old 2003 engine because there was a demand for more power, and VP didn't have a suitable engine at the time.

 

[[70521]]

Is the idea that sail boat engines shouldn't have turbos a thing of the past? would've thought that Yanmar and Volvo wouldn't get something so significant 'wrong'?

Why do they need a turbo?

 

[macd]

Its a power / weight ratio +emissions.
i would not have 1 in a yacht

It also means they can produce a different engine at a fraction of the normal development costs.

Turbos make a lot of sense with diesels, with fewer of the drawbacks associated with petrol turbo engines, which is why you see so many on Europe's roads (something approaching half of all new cars). But for a yacht auxilliary, I'm with you on preferring simplicity. In power boats, it's maybe a different matter.

 

[pmagowan]

What is the downside? Simplicity is fine but not the be all and end all.

 

[Way]

Yep I would agree with that, that's what I was looking for, the downsides.

It's obvious why you turbocharge a diesel, to get more power out of the same engine with very little weight gain. Hence most cars now are turbo diesels if theyre not hybrid.

Rassy use turbo'd Volvos, I can't see that they put something not worthy in their boats, surely?

What is the downside? Simplicity is fine but not the be all and end all.

 

[TQA]

Downside.

It is a bit of added complication, something extra to go wrong.

But the principal downside for me is that turbos run HOT. I would worry about the heat build up. But if the installation takes that into account I guess it would be fine.

 

[macd]

Rassy use turbo'd Volvos, I can't see that they put something not worthy in their boats, surely?

We'll not mention plain brass seacocks, then, eh?

Overall, I wouldn't say it's a huge issue either way, but my leaning is with TQA, above. As well as something else to go wrong, run hot, etc, they don't actually give turbos away. When we re-engined two years ago, that was naturally one of the issues.

 

[Bobc]

I have to say that my gut feel about turbos on yachts is that they're an un-necessary complication.

Having said that, I have one on mine, and it's not been any trouble after 13 years, 2 transatlantics, and thousands of engine hours.

So I'm still of the view that they're not necessary, but wouldn't avoid buying a boat because it had one.

 

[Steve_N]

I see that Beta have just added a new turbocharged engine to their range - the 45, using the same 1498cc base as the 35 and 38.
Although previously their engine range was listed in power output order it now goes 35 - 38 - 45 - 43 -50 on their website, which is a little strange.

Their engine range is listed as 'seagoing' and not 'yacht' though and I can see that a 1.5 turbo engine might be ideal for small fishing boats.

 

[DownWest]

There is quite a difference between the old indirect diesels and the newer direct injection ones that give much higher outputs per cc. and require the turbos to do that. Personally, I run an old Espace road car with a 2.1 Tdi engine and the turbo guage does not often move far off the bottom stop. My neighbour runs a Kangoo dci with nearly the same hp from a 1.5. But I doubt it would function if the turbo quit.
Still, anything that makes a cruising yacht less complicated has merit

 

[sailorman]

I see that Beta have just added a new turbocharged engine to their range - the 45, using the same 1498cc base as the 35 and 38.
Although previously their engine range was listed in power output order it now goes 35 - 38 - 45 - 43 -50 on their website, which is a little strange.

Their engine range is listed as 'seagoing' and not 'yacht' though and I can see that a 1.5 turbo engine might be ideal for small fishing boats.

I have the 37.5hp Nanni ( Kubota) normally aspirated, a brilliant engine. I would not want a turbo on it. 6.7kts @ 2k RPM is good & unstressed. 7.5kts @ 2850 RPM wot with a clean bottom does me

 

[oldharry]

Few yacht auxiliaries die of hard work, most die of corrosion. I doubt if the precision engineering and high grade steels in a turbo would take kindly to the damp salt laden atmosphere of a small boat. Particularly if left standing idle for weeks or months at a time! Fe bikes in the under 500 cc class bother with turbos, as they are simply not cost and weight effective. Turbo charging anything much under about 30hp is probably just not worth it for the marginal gains in size an weight. In any case, turbos need a fairly fast running engine to be effective. Most smaller donks are just that - slow revving (3 -3.500 rpm) plodders.

 

[sailorman]

Ok this is my base engine rated @ 37.5hp @ 3k RPM

How do Beta get 45hp from the same engine @ the same max RPM
http://betamarine.co.uk/wp-content/...al_data_sheets/seagoing_data/B45-SDS-0915.pdf

 

[Beyondhelp]

Turbo operation is related to airflow and nothing to do with engine RPM. You would just design a smaller turbo for a smaller engine. Anything small light and displacement probably doesn't need a turbo, anything else over 50hp and you would be pretty silly not to have really. As for heat, you can ceramic coat the turbine and exhaust pipework. Its very effective you can pretty much touch a manifold just after its been run. Or just use traditional insulation...

 

[pvb]

I have the 37.5hp Nanni ( Kubota) normally aspirated, a brilliant engine. I would not want a turbo on it. 6.7kts @ 2k RPM is good & unstressed. 7.5kts @ 2850 RPM wot with a clean bottom does me

As you've posted, the Nanni is rated at 3000rpm, so if you're only getting 2850rpm at full throttle, maybe you're over-propped? Nanni give the engine an M4 rating, which means full power for no more than 1 hour out of each 12 hours operation, with the remaining 11 hours at or below cruising speed, and no wide-open throttle below the rated engine speed.