Targa 34 fuel consumption?

Good to know! Might start saving for new turbo's for some future point then.

What kind of WOT revs / speed to you get from your KAD44's?
 
Had 2 new turbos on mine (Kad300s) and hit 41knts 3 up 3/4 fuel and water and crusing kit. Couldn’t quite maintain the 41knts but did maintain between 40 and 40.8
 
I have been suffering with under performing boat since Steel developments got hold of my Duo props, prior 47 knots after 43 knots max,

Start of this year I gave them to the owner of the Red Hunton in the Solent, He took a mould of what he deemed to be the best blade on each prop and then made them all match (the did not match after SD returned them)

Next he suggested putting them on differently to the norm. Which is to stagger the blades at 12 o'clock, Mine are now aligned at 12 o'clock. this seems to work better on the Hunton, We are also looking at engine bay temps, The Boat suffers from lack of air circulation and engine bay is getting very warm 90C ish, this has a knock on effect on engine performance,

From what I have found so far it is more than just boat weight there are man factors that affect performance, Of course it depends how far you wish to go. The owner of the Red Hunton is an engineer by profession and loves tweaking with things t get the best out of the boat, He now for example has a maximum engine bay temp of less than 40C and achieves a max speed f just under 80mph while still averaging over 3mpg from Volvo D6's .
 
jrudge said:
Same. All failed test. All refurbed. Performance etc identical !
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I can't remember if I mentioned this when you told me about your experience, but AFAIK a bad injector nozzle could leave top performance unaffected, but still have nasty effects on engine health.

One example is a nozzle dripping/overfueling: the paradox is that at high rpm such malfunctioning can be hardly noticeable - if at all.
But at low rpm, that could ultimately lead to serious damages to the cylinder/piston involved.

That said, it would be interesting to hear from LS1, who surely forgot more about this interesting topic than we will ever know...! :encouragement:
 
Matt infinity said:
Had 2 new turbos on mine (Kad300s) and hit 41knts 3 up 3/4 fuel and water and crusing kit. Couldn’t quite maintain the 41knts but did maintain between 40 and 40.8
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What kind of £ were the new turbo's?

On a related note to the original thread, I am having the Yacht Device NMEA converter fitted shortly which will give accurate fuel consumption figures so I will report back here once I have some data.
 
Ian h said:
I have been suffering with under performing boat since Steel developments got hold of my Duo props, prior 47 knots after 43 knots max,

Start of this year I gave them to the owner of the Red Hunton in the Solent, He took a mould of what he deemed to be the best blade on each prop and then made them all match (the did not match after SD returned them)

Next he suggested putting them on differently to the norm. Which is to stagger the blades at 12 o'clock, Mine are now aligned at 12 o'clock. this seems to work better on the Hunton, We are also looking at engine bay temps, The Boat suffers from lack of air circulation and engine bay is getting very warm 90C ish, this has a knock on effect on engine performance,

From what I have found so far it is more than just boat weight there are man factors that affect performance, Of course it depends how far you wish to go. The owner of the Red Hunton is an engineer by profession and loves tweaking with things t get the best out of the boat, He now for example has a maximum engine bay temp of less than 40C and achieves a max speed f just under 80mph while still averaging over 3mpg from Volvo D6's .
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I had hoped that my props were the reason that we weren't quite making 40kts last year (there were a few visible light dings to a few blades when I bought the boat last year) so set them off to SD.

I'm not sure exactly what they did (I had to double check with them that they had checked bushes were all good, which I had specifically asked them to do) and for spending hundreds of pounds I thought that there would be some kind of confirmation report / print out to confirm their checks on the prop calibration, etc but they just came back in a box (incidentally very much less secure and well packaged than the boxes that I sent them in!).

For all I know they might just have fixed the visible dings......it's not as if they came back visibly different really (not highly polished or cleaned to give the impression that that had been through a thorough process) but then what do I know, you pays yer money to these professionals and trust them to have done their job.

But they didn't give me those elusive few extra knots (but as per other comments on this thread, there could be other reasons).
 
Dan, I think you could drive yourself mad chasing those missing knots. The cause could be one or more of the following...

Sea state
Tidal flow
Boat trim
Wind
Props
Ambient temperature
Fouling
Injectors
Turbo wear
Weight of cruising gear
Etc

What is your boat achieving flat out?
 
37kts at 3700rpm when she went in freshly serviced with clean bottom back in May.

From your list I would eliminate quite a few with a few as question marks remaining:

Sea state - tested in flat conditions
Tidal flow - tested both ways across Poole Bay with little change in SOG so my guess is that tidal effect was minimal
Boat trim - tried a variety of drive trim settings, didn't make a lot of difference
Wind - could have been a minor factor as there would have been a few kts of wind
Props - as above, could be a factor albeit they were freshly refurbished but to what level of expertise is anyone's guess
Ambient temperature - would have been quite cool early May which should have been OK
Fouling - was tested within days of being lifted in with fresh antifoul
Injectors - not tested mine so could be a factor
Turbo wear - as per injectors
Weight of cruising gear - yes, could be a factor even in early season most cupboards are full with something or other - plus on my boat I carry the dinghy on davits at the back, probably acting like a bit of a wind break. I would have had full fuel and water tanks also.

I'm actually more than happy with her performance, we crack 34-35kts without too much effort at about 3300-3400 rpm and as they're not supposed to be run at WOT (3,900+??) for extended periods anyway, having generally fit, healthy and reliable engines is far more important. My initial post on this was more a disappointment that I had mentally put not cracking the 40kts, that reports on T34's with KAD300's state she should do, down to props and the refurbished props didn't immediately make any difference.
 
Dorset Dan said:
Weight of cruising gear - yes, could be a factor even in early season most cupboards are full with something or other - plus on my boat I carry the dinghy on davits at the back, probably acting like a bit of a wind break. I would have had full fuel and water tanks also.
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With a list like that, you can positively replace "could be a factor" with "is indeed a factor".
 
MapisM said:
With a list like that, you can positively replace "could be a factor" with "is indeed a factor".
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P, I agree but note that others are pulling 40kts on KAD300 powered T34's with some cruising gear. And the T34 isn't really the kid of boat that you can load with lots of gear (no jet ribs, gensets or anything like that).

Having read this thread again, I've a few more observations for Dan.

Note that the max speed attained for each boat that came off the production line did vary. Some are faster than others for no apparent reason! Even FL quoted a range of top speeds for each model (37-39kts for KAD44 T34's).

At 37kts, yours does seem a bit lazy. Defective injectors don't seem to make any discernible difference IMO but it is worth getting them tested and fixed when you next have your valve clearances checked. Be prepared for a £800 bill.

It will be interesting to see what boost pressure your turbos are producing as this is likely to be your culprit. I believe that the OEM turbos (not bought from Volvo) are around £800 each.

Did you try running with the engine sync disabled to see if one engine is lazier than the other?

Regarding props, where we are in SCM the growth is pretty dreadful and I often have the legs pressure washed. I don't usually bother touching the props myself but I will in the future give them a bit of a scrub with some wire wool to get the last of the fouling off. You never know, this might give ma 0.5kt or so!

Also, I have C4's on my boat and this is what was fitted when it came out of the factory. I am a little surprised that yours has C6's on it (bearing in mind the relatively small difference in HP between the KAD44 and the KAD300). What does the original builders certificate say was fitted to the boat?
 
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Ian h said:
Next he suggested putting them on differently to the norm. Which is to stagger the blades at 12 o'clock, Mine are now aligned at 12 o'clock. this seems to work better on the Hunton.
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Is it just me, but I can't get my head around how this could possibly make a difference.

I haven't really given it any thought before, but do both props spin at exactly the same RPM, even a tiny fraction of an rpm difference would change the alignment within minutes?
 
Yes they spin at exactly the same rpm, they're duoprop so driven from the same engine (so same rpm),one spins one way the other spins the other way
 
julians said:
Yes they spin at exactly the same rpm, they're duoprop so driven from the same engine (so same rpm),one spins one way the other spins the other way
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I understand the engine rpm but, but each prop runs on a separate shaft and uses a separate gear to make them go in opposite directions. I am wondering if the engineering of these gears is so accurate that over many hours of turning at a couple of thousand revs per minute, they would still be exactly aligned. I am genuinely interested, I really don't know. I would imagine the accuracy of Volvo engineering to be good. But is it that good?
 
CLB said:
I understand the engine rpm but, but each prop runs on a separate shaft and uses a separate gear to make them go in opposite directions. I am wondering if the engineering of these gears is so accurate that over many hours of turning at a couple of thousand revs per minute, they would still be exactly aligned. I am genuinely interested, I really don't know. I would imagine the accuracy of Volvo engineering to be good. But is it that good?
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yep, the gears will be accurately manufactured so things dont 'go out of sync'. If they did go out of sync the gearbox would end up destroying itself.

I dont know what exact drive this boat has, but have a look at this exploded diagram of the duoprop mechanism for a dph drive.

https://www.marinepartseurope.com/en/volvo-penta-explodedview-7744790-44-6307.aspx

Its not possible to anything to get out of sync without a gear losing a tooth. This is exactly why gearboxes have exceptionally fine tolerances.

I guess (but dont know) It would be possible to build it so that one prop does spin at a different rate to the other, but it would be a constant different rate, rather than a rate that varies. and the props would always be in sync every x revolutions - I wonder if any manufacturer has done this, using one smaller but faster spinning prop and one larger slower spinning.

I havent thought about it much, but with regard to the original suggestion of 'clocking' the props, I agree with you that it cant make any difference in terms of performance, because they spin in opposite directions so they will always have overlapping blades at some point in the cycle - maybe I'm missing something - probably am

I suppose it could be something about not having the blades lined up when behind the leg itself...dunno
 
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