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  1. #16

    Re: Noosacat economy

    Try Mick (outta line). He has a 2300 walk around with 150 verados. Had a bit of grief with handling until props were sorted I think. He could tell you where his economy is I am sure. Maybe pm him. Not sure if he gets on here much.


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  2. #17

    Re: Noosacat economy

    I have a 2400 that is quite heavy. I get pretty much spot on 1lt/km all the time.
    Even when fully loaded for a few days out at the reef with 600lt fuel/water/camping gear/ect it doesnít change much.
    Twin 175 Suzukiís

    Yours sounds a bit thirsty, but depends how you drive it too. If I drove mine harder it would be same as yours.

  3. #18

    Re: Noosacat economy

    Quote Originally Posted by gazza2006au View Post
    700 litre fuel tank!!!!! how on earth do u explain that fuel bill to the wife, with a fuel tank like that i would only need to fill up once every 5 years i'd be broke for the next 10 lol
    Gazza...what she don't know wont hurt her..i think in there language its..4 hair doos & nails

  4. #19

    Re: Noosacat economy

    Quote Originally Posted by soulfish View Post
    Gazza...what she don't know wont hurt her..i think in there language its..4 hair doos & nails
    Or 4 pairs of shoes

  5. #20

    Re: Noosacat economy

    Quote Originally Posted by Flex View Post
    Yeah very odd. Motors are on top bolt hole.
    Rex do you have any speed figures at 4000 or 4500 rpm? Unless the turbo offshores are very different than the powertech. What max rpm you get.?
    Iím gunna test a set of 20ís and high cup 19ís.
    First thing I was thinking Flex was motor height comparison, given they are the same boat - albeit with assumed same weight. Top hole or motor at top position (ie bottom hole)?

    Exact same (diam & pitch) 4 blades on both boats? Or just both 4 blades? What type did you try? Sometimes you can jag a sweet change in props with one change, other times it can be damn frustrating.

    Iíve also recently heard that 2400 NCís are running arse-about counter rotating than normal as that provides better handling and prop tuning - at least with the selective rotation Zukes.

    Donít give up mate, can be really frustrating but the end gain is usually worth it .
    Cheers
    Brendon


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  6. #21

    Re: Noosacat economy

    Thanks brendon.
    Regarding motor height itís as high as it can possibly go.
    Props were a different brand but exact same specs. 17p 14,1/4.

    Funnily Noosacat has a boatvtest report on their site with my exact setup when I had the 3 blades on.

    Must be like a new Car report where the figures are exaggerated. Because I get no where near what Yamaha states.

    Their results are
    4500rpm for 61km for 61litres.(which is good economy)

    My results with identical setup is
    4500rpm 61km for 70litres.

    Running light to, gets smidge worse when running heavy.

    Iím swapping my 4 blade 17ís and gunna try set of 3 blade 20ís.

    See if I can jag more speed for the same fuel burn.


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  7. #22

    Re: Noosacat economy

    Maybe even though the motors are as high as they can go, they are still low?

  8. #23

    Re: Noosacat economy

    the one bit of info you havent provided was the rpm at wot. You would want to get the full rpm range on the prop. all this talk of going from 17" to 20" would have me worried. I dont think there is much difference between a 4blade 17" and standard as far as ouright speed or economy goes, your just changing the points of power delivery. Going to 20" is just going to bog you down. I would be inclined to go 15" to make the motors boogie. I dont understand the fear of over reving as they all have some kind of over rev control, but getting bogged down or inadequate performance is somehow more acceptable. Smaller pitched prop means the motor spins easier and has less load which should equate to better economy. Dont think that because its a yamaha it should have the same sized props as other makes.

    check this out

    And those videos that show the yamaha motor not being able to get the boat on the plane, ha, bullshit artists. Drop the prop size and it will !!

    In your case, your only interested in the 4-5000rpm range so I wouldnt worry about topend speed so much.

  9. #24

    Re: Noosacat economy

    Quote Originally Posted by Flex View Post
    ...
    Regarding motor height itís as high as it can possibly go.
    Props were a different brand but exact same specs. 17p 14,1/4....
    Re motor height, see Noelís reply. Are they still too low? Do they ventilate easy at normal trim or not at all? How much +ve trim before they let go?

    Prop pitch in any prop size is Ďan estimateí, unlike the diameter, which can be physically measured. Different brands same size spic means they will be close, but not the same. Can you try/borrow another set of props on the same boat/model that you know work better?

    Quote Originally Posted by Flex View Post
    ....Funnily Noosacat has a boatvtest report on their site with my exact setup when I had the 3 blades on.

    Must be like a new Car report where the figures are exaggerated. Because I get no where near what Yamaha states....
    Are you comparing stats from ideal conditions (where thereís will be tested - in the river probably), or your real world conditions?

    Boat weight? If yours was a rescue boat then it definitely was built to survey and was obviously Ďin surveyí for some time. Could easily be heavier than a rec boat same model. Wheghbridge is the only way tri know.


    Quote Originally Posted by Flex View Post
    ...Iím swapping my 4 blade 17ís and gunna try set of 3 blade 20ís. ...
    Thatís a huge jump in pitch! I doubt they will work well unless the 17ís are under propped, and/or they are a tall prop and the 20ís are short. But try them anyway.



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  10. #25

    Re: Noosacat economy

    Flex i'm the same mate, just bolted on F150's on a 660 noosa cat (simular weight) Built bigger pods to float them.
    Very dissapointed in econemy, The noosacat tests are with 110ltr of fuel and in the creek which is a dead set wank. I have just trialed a set of powertech 18's and in calm conditions in tin can straights i averaged 1.08ltr a km and hit 45 knts full fuel with the cook and kids driving it reasonably hard. Thats good i would have thought, but recently i did a trip in some swell and it all change. Did 318km for 430ltrs. 1.35ltrs a km driving like a girl,22 to 24 knts until we came home at 28knts which the boat felt happy then and burnt less juice for the trip home which makes me think i need to go back to a 17 with less cup. Frustrating as f@@k mate especially when blokes with 2700's are getting 1.4ltr a km and another 2700 i know of getting 1.5ltr a km, then theres a 3000 series KC i know of and he gets 1.5 to 1.6ltr a km.
    I'm trialling 4 blades 16's soon as i need eco more so than speed as i cant sit on 30knts everywhere off fraser and range is a higher priority.

    Rexaway...Out of curiosity what was your fuel figures swinging the 19 standard black prior to you going 4 blades?

  11. #26

    Noosacat economy

    Quote Originally Posted by Flex View Post
    ...Iím wondering if the f150 yammies are just a thirsty engine?
    Surely the 2300noosacat isnít that much heavier (maybe couple hundred kg at best)than 2400KC.
    They seem to get great economy and awesome speed from the 140ís...
    I wouldnít say thirsty Flex. Strong, yes (check the EPA test data), but no thirstier than any other Ďsame gení four stroke.

    The boat specs available online show that there is approx 350-450kg difference in these boats with max rated donks (NC heavier), and from observation of boats, std fitted motors, trailers and tow setups over the years, and performance figures etc, I would say this indeed the case. Slightly different hull design too.

    A mate in my fishing club has a NC 2400 with 150 Zuke APís. Sub 1km/L if he travels too slow, but around parity or 1.1 occasionally if at 50kís and calmer conditions. Another guy I know with same boat, slightly heavier but 175 APís gets marginally better economy I think (0.1), but is also running a pitch larger props (due to extra HP). No precise stats sorry.

    One thing is for sure, from my research and recent mates motor upgrades, is that the Ďcurrent gení 4/Ďs are indeed 10-15% better on fuel, and across all brands too. And, E-TEC G2ís a lot better than G1ís etc. Would it warrant an upgrade on economy alone? IMHO, no, but if factoring in other +ís (incl range), maybe ).

    Quote Originally Posted by Flex View Post
    ...Anyone have a similar boat and can share exact fuel usage?
    Not many blokes have precise fuel burn figures....
    I can now .

    Similar, yes, but bigger and heavier, and a different hull design - but still a cat . 2018 Powercat, real hull size 7.6m(25í), plus pods x 2.8m(9í) beam x ~3000kg dry hull weight (weigh bridge, give or take a few kgís depending how close the trailer TARE is to the plate). Hull design itself hasnít changed in 30yrs, and is the same as the old Powercat 268ís. Zuke 200APís, 3 x 16 x 20 Zuke props.

    Some recent performance figures in glassy conditions, which from other trip stats, counteracted the reduced crew weight anyway as she was sticking to the glassy calm water a bit .

    These figures were with just me on board, only 15 hrs up on the donks, ~250L fuel & ~120L water, ~ 125kg gear. On other days with 4 or 5 adults and a lot more weight/liquids, the figures at 25 Ė 30kn donít change much from below even in 15-20kn Moreton Bay conditions Ė at least from what I have seen anyway.

    All the readings below were from the gauges except for the last column [km/h], which I calculated as I didnít write them down. Fuel data is the combined Total for BOTH donks.

    rpm, kn, L/nm, km/L, L/h, [km/h calculated]
    3000, 15, 1.8, 1.0, 26.4, [28]
    3200, 18, 1.5, 1.2, 28.6, [33]
    3400, 20, 1.5, 1.2, 31.2, [37]
    3600, 22, 1.5, 1.2, 33.8, [41]
    3800, 24, 1.6, 1.1, 38.6, [44]
    4000, 25, 1.6, 1.1, 42.8, [46]
    4200, 26, 1.8, 1.0, 47.2, [48]
    4400, 27, 1.8, 1.0, 49.0, [50]
    4600, 29, 1.8, 1.0, 54.7, [54]
    4800, 31/2, 1.8/1.9, 1.0, 60.4, [57]

    In comparison to my last boat (685 + F250, pics attached for size comparison)... ĎIFí conditions allowed, and I could travel as fast in the old girl, there would be no difference in economy! Brilliant performance really, especially considering the cat is ~1100kg heavier dry, and has 400HP instead of 250!

    A mate owned the same hull boat, with 2007 model 200 V6 Zukes, and I am about 20-25% better economy it seems with the 4 cyl APís. So... the current gen donks are indeed very good with performance/economy.
    Cheers
    Brendon IMG_8961.JPG


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  12. #27

    Re: Noosacat economy

    Quote Originally Posted by Andy56 View Post
    Smaller pitched prop means the motor spins easier and has less load which should equate to better economy.
    Not necessarily correct. I have found exactly the opposite with my E-Tec. Because it has such high torque, it will quite happily punch the boat out of the hole with a prop that is too high in pitch (to a point) and return fantastic economy numbers. The best numbers I have seen were with a prop that resulted in WOT rpm being 500 revs below "optimum". I ended up settling on a prop that gives a WOT of 200 revs below optimum. The closer I get to optimum, the lower my best economy numbers go and going over optimum WOT rpm with too smaller pitch produced woeful results.

    Talking to various boat builders back in the day when 4 strokes first started coming into vogue led to an opinion that provided the weight penalty is not significant enough to induce handling issues, you get better results by fitting higher horsepower so that cruise revs can be kept below the magic 3500 mark. There is more to it than just RPM though. If the hull isn't happy with the speed at a given RPM and isn't actually working efficiently, it can markedly decrease the economy. As such having a higher horsepower capable of swinging a bigger prop at WOT can in some circumstances put a hull right in it's sweet spot at a more economical RPM whereas the smaller engine with a smaller prop is running outside it's most economical RPM range to generate the boat speed required to make the hull work - but can't run a bigger prop to the required RPM. It's a delicate balancing act at times.
    "I soak the worms in rum. The fish love em and the worms die happy"
    "Alcohol is not the solution to your problems...................but then again, neither is milk"

  13. #28

    Re: Noosacat economy

    Completely agree Scott. Itís probably more relevant to cats too. They need to be moving at a certain speed before they become efficient. Each cat design will be different and some are better than others. I know with mine the speed is around 22-23knots. From memory with the little 60ís thatís at about 4700RPM. Some will consider those to be very high cruise RPM but they seem to do it effortlessly and the economy reading constantly flicks between 1.4 and 1.5km/l. Which of course is crazy good economy running twin engines of any size. The fuel used for km traveled marries up also. For a 135km trip Iím always around 100litres used when I fill up and that takes into account a lot of time with them idling while drifting, pulling anchor etc.. WOT of 29 knots @ 5800RPM drops it back to 1.3Km/L
    Democracy: Simply a system that allows the 51% to steal from the other 49%.

  14. #29

    Re: Noosacat economy

    Yep, I also can attest that cats produce the best economy above 20kn, but not WOT LOL. Also lifting the nose up also help a fair bit and crazy enough it uses more fuel in glass out condition as to sea with around 10kn wind. My twin 140s get about 0.8 to 1 Lt per kay depending how much of a hurry I am in, and I consider myself to be a lazy boater, mean I set and forget and just turn the wheel.
    Humility is not a weather condition.

  15. #30

    Re: Noosacat economy

    That is some unbelievable fuel economy gofishin your getting. I have early mod 2016 F150XB's on my cat and there 10% worse than my 02 mod mercury 115;s on fuel. I'm a tad worse than flex on fuel economy as well.



    Trialing the same 4 blades soon on a loaded trip to see if it makes a difference. The 3 blade 18's would lug in the arse at 24 knts and feel a bit boggy in swell when loaded on a trip. Hoping the 4 blades will lift its fat arse in the midrange revs in swell and keep her up. i will let you know how i go.

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