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55' Roamer Speed Capability

Discussion in 'Chris Craft Roamer Yacht' started by AllPoints, May 17, 2016.

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  1. AllPoints

    AllPoints New Member

    Joined:
    May 14, 2016
    Messages:
    7
    Location:
    Cleveland Oh
    So we just purchased our 55' Roamer we were planning on taking the trip from Buffalo to Cleveland today.
    The broker insists the boat should run at 18-20Knots, which would make the trip about 10 hours.

    BUT, the previous owner says he consistently runs the ship at 10Knots making the trip 20 hours. The owner says the ship will go that fast but burns through the fuel.

    The broker specializes in Chris Craft Yachts says he moved the sister ship a few years back and easily ran at 20Kn.

    The ship has dual 8V71Turbo charged engines.

    I'm very new to a ship this size. Would I be pushing the engines hard running at 18-20Kn? Was the previous owner just babying the ship for the past 20 years?

    Any help from the community would be welcome.

    Thank You
    -Captain James
    IMG_0451.JPG
  2. JimmyL

    JimmyL Member

    Joined:
    Aug 27, 2014
    Messages:
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    Location:
    Victoria, BC
    I'm not sure what your question is but diesels like/need to be worked but the added fuel cost makes it expensive to run at that speed not to mention the passenger comfort and the sheer pleasure of the trip. Picture your kid hammering the throttle of your prized Eldorado around town... It can be done but why?? My boat will also do 20 knts which is great when needed and I'll run it up there every once in a while just to exercise the power but 10-12 kn is where she likes to be and is the sweet spot for economy.
  3. NYCAP123

    NYCAP123 Senior Member

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    The sweet spot for those motors should be about 80% of max RPM, HOWEVER if the previous owner constantly ran at 10kts. I'd keep a real close eye on the temp and oil pressure guages, and watch for oil leaks.
    Think I'd break that shakedown cruise into a 2 day trip, and run as JimmyL suggested "run it up there every once in a while just to exercise the power but 10-12 kn" most of the run.
    P.S. Run by the tach, not by the speed. The speed will vary depending on current, wind, etc.
  4. olderboater

    olderboater Senior Member

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    You need to obtain a manual. They're widely available online. See what it says as far as how frequently, how long, and at what load you need to periodically run it. RPM is not load. On every boat we own, 80% RPM is well under 80% load. In most cases 80% load is about 86% or so RPM.
  5. olderboater

    olderboater Senior Member

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    Actually most of the time they recommend 80% load, not 80% RPM On all our boats 80% load seems to average about 86% of maximum RPM's, so 80% RPM would seem a safe conservative level, but I still try to do up to 80% load. However, I do not know the recommendation on your engines, and I'd recommending getting a manual and seeing what it says. They are readily available online.
  6. chesapeake46

    chesapeake46 Senior Member

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    They're DETROITS.....they're gonna leak.:)
  7. Capt Ralph

    Capt Ralph Senior Member

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    Messages:
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    Location:
    Satsuma, FL
    Detroit Diesels have always had a bad rep as oil slingers. I have witnessed more oil in the bilge than in the block a few times. Uuuck.
    It does not have to be.
    I just can not bring my self to replace the tach drives on the back of my 12v71ti's. I shoot a shot of grease in them every 6 months but the oil does win, It's my only oil leaks.
    I've kept up other 12Vs and some straight 6s. It's a chore but they don't have to be oil slingers.
    Picked up another customer with 671TIBs. It's going to take a long while with all the slobber blowing out, But it WILL be clean when I'm done.
    Lil bit at a time, in about a year.

    8V71s can have a clean life also. It takes time and patients.

    Back to the OP, Ya wanna run fast, don't watch the money gauge (fuel gauge) on the dash. It's always fun for a broker to run somebody elses boat when it's not his fuel.
  8. Capt J

    Capt J Senior Member

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    cruise RPM with your engines should be 1950 rpms. They'll burn around 60 gph for both and it's highly likely the boat will cruise at 20 knots with a clean bottom and trim tabs. That being said if you run them at 1000rpms they'll burn about 8 gph for both and probably do 9 knots or so. Not easy to figure out which is a heck of a lot more economical. However, Detroits don't like to be run there endlessly and all of the time. Many times on yachts like yours I'll run them 1000 rpms and every 5-6 hours run them up to 1950 rpms for 30 minutes to clean them out.

    And, I've always found that Detroits will always leak oil.
  9. Capt Ralph

    Capt Ralph Senior Member

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    It's all with the 71 Zen.. Keep thinking good vibes as you get close with your 71.

    Probably one of the big problems with DDC oil leaks, is finding where the heck they are leaking.

    Time, OPM and lots of loctite 515.
  10. chesapeake46

    chesapeake46 Senior Member

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    I should clarify my point. Oil leaks on a Detroit are not the end of the world.
    It'd be nice if they didn't but you should not be scared if they do leak.
    If they leak like a sieve, then I'd worry.