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Bertram 54 propeller

Discussion in 'Bertram Yacht' started by radmiral, Apr 13, 2011.

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  1. radmiral

    radmiral New Member

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    I need to replace a bad set of props that came with my 1988 54 with 1292 's . They are 4 bladed and look like they have been redone. I only get 23kts WOT at 2300 . Does anyone have experience 3 versus 4 blades,and what size ?
  2. Loren Schweizer

    Loren Schweizer YF Associate Writer

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    Your 54 Bertram came out of the factory with 30 X 34 wheels with a slight (B or C) cup. The base boat--2/3 fuel, 2/3 water, 6 people, 2000lbs gear--with no tower or dink or sixty cases of Heineken should see you over thirty kts.

    Likely, the previous owner changed props. Simplified version: 4-bladed props help mitigate vibration albeit with slower speeds while 3-bladed props deliver more performance ( which is why they were OEM).

    Maybe there was a vibe issue due to shafts or struts or engine alignment(s) out of whack and the situation was 'band-aided'.
  3. radmiral

    radmiral New Member

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    There is vibration with the 4 bladed reconditioned props. I have someone with a good price on 3 bladed , but now I am concerned about needing to deal with the shafts and rudders. I am inclined to buy the 3 bladed ones and when I will haul the boat , deal with those issues. Do you have an idea what shaft alignment and rudder job should run?
  4. Capt J

    Capt J Senior Member

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    Shaft alignment is done with the boat in the water and is basically only time, and adjusting the height of motor mounts, and possibly side to side slightly. You could check this yourself with feeler gauges, you could even align the motor yourself if you have mechanical aptitude. Google it and you'll see how to check it and then decide if you want to hire someone.

    Checking the trueness of the shafts should be done out of the water when the boat is hauled. A rudder job, do you mean changing the rudder bearings and repacking them and everything? Price depends on what equipment you have, but I'm guessing non dripless. To pull the rudders, change bearings, repack, and possibly a part of two, I would guestimate $2k for both. A yard could tell you better.

    I have run a 1984 54' Bertram that was light, back in 2004, it had 4600hrs on 12v71TI's (origional no rebuilds), it had little fuel, no tender, just a hardtop, and it hit 30 knots.....I was very impressed with it.
  5. Ormond Bert54

    Ormond Bert54 Senior Member

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    I have a 1984 Bertram 54 ... 12V71TI engines (800 hp each) 3 blade 28x30's stock that are now 28x28's after years of abuse, reconditioning etc. My gears are 1.51 / 1.

    I am not happy with the performance of the boat ... am pursuing new propellers once I finish with the overhaul of one of the engines (for the second time in a year .. long story).

    The prop shop is going to pull both props to verify again that they are indeed 28x28 as they are now. Will also verify RPM's with a photo tachometer.

    Prop shop concurs that 4 blade does not buy more performance ... also says 4 blade does not mean smoother but I have heard from many that 4 blade does mean smoother performance.

    I'm hoping for WOT performance of 29 knots and cruise of 20-22 knots.

    I am aware of a Bertram 54 with my same engines running 4 blade Michigan Wheel "Dyna-Quad" 28x30 props ... difference is that his gears are 1.75 to 1 and not 1.51 to 1 like mine.

    His performance is 22 knots cruise ... 29 knots WOT. Where I want to be.

    Either way ... slapping on a different set of props will not solve the issues of vibration or performance. Working out the issues carefully with some trusted professionals should.

    PM is you want to continue communicating about the craft ... we have different engines but it's nice to have folks to talk to who have a similar craft.
  6. K1W1

    K1W1 Senior Member

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    Hi,

    While your engines may get to 2300 RPM do you have any idea of how close this is to max load?

    If you are under propped you will achieve full RPM out of the engines but not get the same drive if the props are too small compared to if they were the correct size and pitch.

    A stain gauge on the shaft is an accurate way to tell what is being produced by the engine, if not available the next best thing would be fuel flow metering showing what is being burnt.
  7. radmiral

    radmiral New Member

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    I have not installed a flow meter and have only sight gauges on the tanks. I have gone a couple of times from Miami to Bimini and seem to be burning too much. I was cruising at 1950 at 20 kts Not Covered
    *It is a full tower boat and have a Davit and 12 foot Dinghy. I have some vibration.
    *
  8. Loren Schweizer

    Loren Schweizer YF Associate Writer

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    radmiral, your boat has "issues".

    Gilbert over at Glasstech on the river can offer you advice on the fix. It will not be inexpensive, but he's done this for many years and has seen it all. Rick at Norseman has performed this fix for a long time as well.

    Your strut installations at the factory were done by eyeball; they were not lasered. If somebody whacked a wheel, and the shafts are out by more than .006", they need to go to a machine shop for straightening.
    Who balanced the props? A guy with a hammer? A good prop shop in required.

    As CaptJ recommended, an engine alignment with the boat in the water is needed...those engine mounts may be worn out as well.

    There is generally no one single thing amiss here; it's a combination, likely, of three or more areas to check.

    BTW, your (stock) gears are ZF 195 1.5:1
  9. Capt J

    Capt J Senior Member

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    You have a lot of weight on the boat compared to standard trim, between the tower and dinghy davit. Try running the fwd fuel tank dry first and using the tabs if needed to keep the bow down. Sportfish like to run light in the bow for speed and performance. See if that picks up your speed any, it should pick up a couple of knots at cruise. Drain the cockpit tank last. However, adding a tower generally slows a boat down 1-2 knots, and adding a dinghy/davit usually slows the boat down another 1-2 knots.

    Now I see why someone switched to 4 blades. They are generally better at keeping a heavy boat on place such as yours because they have more blade area and bite. Albeit at the expense of less speed. A lot of boats it really doesn't help keep them on plane or offer any advantages over 3 blades except slower speed and slightly less vibration. It sounds like you're close on rpm's. Are the engines supposed to go 2350rpm's at wot or 2300? I ran a set of Covington 12v71 TI's and they were only supposed to turn 2300rpms. I would try a set of 3 blades and see. How many hours are on the engines and who marinized them, what HP? And, if they're JT 12v92's plan on them using a lot of fuel. How much did you burn going to and from Bimini?

    As for the vibration, I would 2nd Glasstek as they are probably more knowledgable on your boat than the people at Bertram are. I've heard good things about Norseman also. Have them check engine alignment in the water, then check shaft alignment out of the water.
  10. mysue

    mysue Guest

    My 83, 54' Bert has 800 hp 12v71's & will do 32kt's wot with 4 blade 30x34's. Motors have 1800 hours. I'm haappy, although I seldom run her that fast. Mostly putz around at 8-900 rpm, only running up to wot to clean the turbos out.