Beta 35 or 38

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billiew

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I have decided to replace the Volvo MD17c in my Westerly Solway ,Beta seems to be most peoples choice but I am confused as to why they have a 35hp and a 38hp in their range.I know the 38hp revs higher to get the extra hp but cannot see why they offer the 35hp,there is very little extra cost and the 38hp can be run at 2800rpm,as indeed it would be mostly.
Am I missing something here?
Bill
 
No,its not Nanni v Beta,I know they are very similar and based on the Kubota engine,I have decided on Beta but am trying to decide between the 35 and the 38.I can't see why anyone would buy the 35hp when the 38hp offers more power for very little more,after all we don't run at full revs all the time but the extra is there when needed with the 38hp.
I think I may be missing something,I have talked to Beta and they are helpful but not given a definitive answer other than to say it's your choice.
Bill
 
I don't know the differences between those two engines but if I was you I would go with the more powerful one. Around 8 years ago we replaced the MD11C in our Pentland with a 35hp Beta engine. I was so dissapointed when we left the boat yard on the first cruise with the new engine. It was much quieter and smoother but did not have the torque of the old Volvo. Some of it was due to a different propeller (beta runs the opposite way to Volvo). We ended up increasing prop size and changing gearbox but could never get the same performance that the Volvo had.

I must stress this is different to a lot of other peoples experiences.

Our new boat has a Nanni and I love it ;)
 
Yes,the MD 17c is 3 cylinder rated 36hp at prop.I can't see any reason to fit the lower powered engine when the more powerful one is so similar in price,I can of course run it at lower revs most of the time and would do so but the extra is there when needed.I run the Volvo at 1800-2000rpm when it is rated at maximum 2600rpm
Bill
 
billiew said:
Yes,the MD 17c is 3 cylinder rated 36hp at prop.I can't see any reason to fit the lower powered engine when the more powerful one is so similar in price,I can of course run it at lower revs most of the time and would do so but the extra is there when needed.I run the Volvo at 1800-2000rpm when it is rated at maximum 2600rpm
Bill
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As Beta stated, "Its your choice", good luck
 
billiew said:
I have decided to replace the Volvo MD17c in my Westerly Solway ,Beta seems to be most peoples choice but I am confused as to why they have a 35hp and a 38hp in their range.I know the 38hp revs higher to get the extra hp but cannot see why they offer the 35hp,there is very little extra cost and the 38hp can be run at 2800rpm,as indeed it would be mostly.
Am I missing something here?
Bill
Click to expand...


The euphenism often used is "for Commercial Reasons". A few extra hundred quid, for an engine that costs the same to produce, makes a big difference to profitability. It is a bonus if the "larger" engine stacks up against offerings by a competetor, in one market or another.

I would look at the fuel consumption and see what each engine is putting out in your chosen RPM range. Probably little different and you will go for more headline power - that's why the crafty monkeys do it.
 
Just noticed you have a Solway. When I first read your post for some reason I thought you had one of the 31's. Are you sure the engine is big enough - we have a Conway and a 43hp Nanni and I don't think I would want less power than that.
 
Kubuto or whatever manufacturer offer the same basic industrial unit with different rpm output to suit whatever application is needed so a generator or mini digger may prefer a different output. I think the mechanical difference is very small as the rpm is set by a governor that meters the fuel to the pump so probably a 35hp could be altered to 38hp by changing a part like the camshaft that contains the governor . Beta offer the choice because there is no reason not to , yachtsmen seem to have a lot of differing and sometimes weird ideas about propulsion some are happy with an egg whisk while others want just poweeeeer.
 
You need to consider also the reduction ratio of the gearbox as that will determine the size of propeller you can use. This has a significant effect on the maximum speed potential. With the original MB 42hp engine fitted to the hull maximum of 7.7 knots could be achieved with a 16" prop. If you are limited to a 16" then the 35 will only get to 7.2knots, although if you can swing a 17" you can fit a 2.4:1 reduction and get it up to 7.5. However if you go to the 38hp and a 2.4:1 you can still keep a 16" and achieve 7.7 knots which is the "theoretical" maximum displacement speed. All figures come from the Propcalc programme.

This is leading towards the 38 as being the better choice. Your cruising speed will be similar with either engine and no difference in fuel consumption, but you have potential for an extra .5 knot. A significant factor in these calculations is the weight of the boat. If it were a ton lighter the 35 would be the choice - for example, my Bavaria 37 at 5.7 tons (compared with your 7.7) is quite happy with 30hp.

Hope this helps.
 
Thanks everyone for your input,I am inclined towards the 38hp since it is only about £125.00 more.Can't really see any downside and the extra hp will be useful if only occasionally.
Tranona incidently I am using a 17x11 prop at present on the Volvo setup 1.91:1 I believe.This gives me just over 6 knots at 1900-2000 rpm.No idea of speed flat out(2600rpm) don't like to push an elderly engine too hard which is one reason I think it time for a change.
Thanks again
Bill
 
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The 17" prop is because you have a lower shaft speed (approx 1300) with your current setup compared with minimum of 1500+ with the higher revving Betas. You could use a 17" with the 38 and 2.4 reduction. You need a new prop though as the Beta runs the other way - although think you can get the TMC 60 to run LH but I don't know what the reduction is. Might be useful if you have a fancy expensive prop rather than buying a new one.
 
Tranona said:
The 17" prop is because you have a lower shaft speed (approx 1300) with your current setup compared with minimum of 1500+ with the higher revving Betas. You could use a 17" with the 38 and 2.4 reduction. You need a new prop though as the Beta runs the other way - although think you can get the TMC 60 to run LH but I don't know what the reduction is. Might be useful if you have a fancy expensive prop rather than buying a new one.
Click to expand...

go for the PRM 150 box, quiet & bullet proof & can spin both hands so the existing prop might do
 
My prop is not a fancy one but was new about 4 years ago so don't want to change it if it can be avoided so the PRM 150 box sounds a good choice.A friend fitted a Beta 35 a couple of years ago and had a conversion to his box so he didn't change his prop,he also replaced a Volvo MD 17 with LH prop.It has an extra gear to change direction of drive,he says it is noisier than before so I won't go that route.Thanks for all your input
Bill
 
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