Bukh 20 -> Beta 20 bed issues?

[doug748]

Just read what I said in post#8. The advice was conditional - if the boat exceeds 4 tonnes then it is better to go for the 25.

It is your comment that seems "odd" as you are categoric that he only needs 20hp when you have no idea what boat he has in mind.

Basing it on the possibility that it was a similar type to his existing, and taking note of this little hint:

" A lot of the ones I see are powered by old Bukh 20 raw water cooled engines (223Kg) and I would re-engine with a Beta 20 (100kg)."

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[Tranona]

Fulmar, 4500kg. My Dehler is 5300kg and has a Yanmar 30 which is very, very rarely run above 2500 revs.

I do think 25hp is better, but not if I have a 2 year old Beta 20hp to hand. We will know soon.

Image shows bow damage on Seawolf. A goodly bit of delamination on s/b side. I think it is on its way to the scrap yard. Hopefully not.

Yes. I have had 2 boats of similar size and displacement to your Dehler both with 30hp engines and cruised at 2200-2500. Rarely went above that, but the reason such boats cruise easily at about half power is that you need the full power to get comfortably up to hull speed. If you have a 20hp engine is such boats you have to cruise at 4-500rpm higher with less reserve. The engine does not object but the increase in noise is significant and you forgo that reserve for adverse conditions.

The 25 is the better choice for the Fulmar if that choice is open to you. some fulmar owners like Roger (concerto) have a 28hp Beta (now superceded by the 30) but that is not necessary. Having said all that the Beta 20 will be a big improvement in terms of refinement.

 

[Tranona]

Basing it on the possibility that it was a similar type to his existing, and taking note of this little hint:

" A lot of the ones I see are powered by old Bukh 20 raw water cooled engines (223Kg) and I would re-engine with a Beta 20 (100kg)."

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You are selective with your choice of words to quote. He was referring to "alternatives" which turn out to be Fulmars.

Better to read what is written than making up your own "possibility" which was not there before wading in.

 

[doug748]

You are selective with your choice of words to quote. He was referring to "alternatives" which turn out to be Fulmars.

Better to read what is written than making up your own "possibility" which was not there before wading in.

Well it turned out all right in the end, we both agree that his engine will be fine in the Fulmar.

Whilst you are dishing out advice about subjective matters, I must ask you to apply more rigour to objective ones. From a recent thread:


Me:

"My guess is that a new basic Beta 20 would be around 6k"

You:

"Prices have just gone up again and close to £7k for the base engine now."

dgadee above:

"For interest, Beta gave me current pricing (including discounts):

• Beta 20: £5664.00 delivered including VAT.
• Beta 25: £6068.00 delivered including VAT."

Against my better judgement I let that matter rest, always a mistake where false information masquerades as advice.

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[Kwik Decision]

Going back to the OP's first post, where it is implied he wishes to re-use the prop shaft. When we replaced the Bukh DV20 on out Sadler 29 with a Beta 25, we needed a new prop shaft, as the old one was too short. Not a lot of cash in the context of re-engining, but something to consider.

 

[dgadee]

Going back to the OP's first post, where it is implied he wishes to re-use the prop shaft. When we replaced the Bukh DV20 on out Sadler 29 with a Beta 25, we needed a new prop shaft, as the old one was too short. Not a lot of cash in the context of re-engining, but something to consider.

Yes, had to do that when I went from a GM to YM Yanmar. I got it made up at a small engineering factory near me from a length of 316. Only afterwards did someone say to me, was it straight? I assumed it was but I should have checked. Pretty sure it is ok - we have done a good few miles with it.

 

[justanothersailboat]

There's an alternative to a new shaft if you just need to take up 7-10cm because you fitted a new engine. I think they're called shaft bobbins? a turned steel fitting that fits between the gearbox and shaft end. Not cheap but can be cheaper, and faster to get, than a new shaft.

Unfortunately for any given bolt circle size (matches the flexible coupler / gearbox flange; there are only a few) there is usually only one bobbin length commonly available. I ended up with a second flexible coupling as well to take up the space because I was impatient. That might not have been cheaper. It should in theory provide really good vibration reduction but a new Beta is so much smoother than many crusty old engines I will never know how much to attribute to this extra help.

 

[dgadee]

It should in theory provide really good vibration reduction but a new Beta is so much smoother than many crusty old engines I will never know how much to attribute to this extra help.

The Beta is very quiet and it has been commented upon several times, so not just my imagination.

 

[GHA]

looks like the 25 feet are tiny bit closer (in height) to the prop than the 35 I fitted & is shorter.

This worked well when I swapped. Rebated the bolts coming up into the feet & filled with epoxy to the timber sits flush.

 

[Tranona]

Well it turned out all right in the end, we both agree that his engine will be fine in the Fulmar.

Whilst you are dishing out advice about subjective matters, I must ask you to apply more rigour to objective ones. From a recent thread:


Me:

"My guess is that a new basic Beta 20 would be around 6k"

You:

"Prices have just gone up again and close to £7k for the base engine now."

dgadee above:

"For interest, Beta gave me current pricing (including discounts):

• Beta 20: £5664.00 delivered including VAT.
• Beta 25: £6068.00 delivered including VAT."

Against my better judgement I let that matter rest, always a mistake where false information masquerades as advice.

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No we do not agree - neither does the OP as he expresses a preference for a 25 if he were buying new. It is a matter of fact that the Fulmar is underpowered with 20 hp for the reasons given in post #8. The boat needs 21.8hp to achieve hull speed and the notional 20hp delivers 18hp at the propeller. Hence my sound advice that a 25hp which delivers 23.9hp at the propeller is the better choice and well worth the £400 or so extra if buying new. Of course fitting a 20hp is not the end of the world - just means higher revs for a given speed and a potential loss of performance in adverse conditions, not least because of the smaller propeller with the smaller engine, but it is sub optimal.


With regard to prices, it was full retail price I was quoting - must remember to be more precise knowing the nitpickers that are around.

 

[doug748]

..........With regard to prices, it was full retail price I was quoting - must remember to be more precise knowing the nitpickers that are around.

You make a pointless and misleading response to my accurate post and that brands me a nitpicker ?

What is life like on planet Zog?

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[dgadee]

Well, in the end one quotation has come infor repair of Seawolf which is 1/2 what a couple of early phone calls suggested. No need for an engine transfer. A Fulmar may have to wait for a year or two.