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Tiara 3800 Open Performance Data

Discussion in 'Tiara Yacht' started by dscaring, Apr 24, 2018.

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  1. dscaring

    dscaring New Member

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    Looking at purchasing a 2002 Tiara 3800 Open with 450HP Cat 3126-B's (electronic).

    Unfortunately all Tiara 3800 performance data I've seen online (forums, Boattest.com) etc, are with the Cummins 450HP 6CTA 8.3-M2 diesels. Those reports show cruise around 26 knots (30 mph) @ 2250 rpm and ~30 gph (1.0 MPG)

    During sea trial with the twin Cat 3126 (with Cat mechanic onboard) we recorded a cruise of aprox 21 knots (24mph) @ ~2100-2200 rpm, and fuel burn of 18 gph per engine (36 gph total) or 0.66 MPG

    Is it possible that the Cummins are that much more fuel efficient? I've asked Tiara if they have performance curves for that vessel with both engine configurations, but i have not received any info yet.

    Any insight would be helpfull.

    Thank you
  2. Capt Ralph

    Capt Ralph Senior Member

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    I think these Cummins numbers are on a very light boat.
    Attached are the Cummins graphs.
    I do not have the Cat graphs.

    I've turned into a 8.3 fan also.

    Attached Files:

  3. dscaring

    dscaring New Member

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    Thank you very much for the response. I also was skeptical of the boating magazine reports (assumed a very light load) but i've seen many 3800 owners, quote similar numbers from their real-world experience with Cummins power. My boat during sea trial was definitely loaded up (full fuel and water tanks, 6 guys), i just didn't think that would account for such a huge difference in performance numbers (5 knots and 0.3 MPG at same RPMs). Thanks again
  4. Capt Ralph

    Capt Ralph Senior Member

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    I think the 8.3s spin faster a bit so it's hard to compare rpm to rpm.

    Lets find a Cummins powered boat and go for a trial on her.....
    Even a fish charter.
  5. Capt J

    Capt J Senior Member

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    Isn't cruise on 3126's 2400 RPM's, I'm almost sure it is. What is your speed there? 450 HP 3126's usually burn 45 GPH at 2400 rpms. What was your speed/rpms WOT? You have to remember you're also looking at a 16 year old boat with most likely numerous coats of bottom paint etc. The 450 HP C series cummins I ran in real life burned 40 GPH at cruise in a 35' Carolina classic. I ran it from Pensacola to Cape Cod.
  6. dscaring

    dscaring New Member

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    Thanks Capt J. I'll have to call the Cat mechanic to find out what we were running at 2400 rpm's. I took a photo of the Cat display while at WOT. Numbers were...

    RPMs: 2715 Port, 2794 STBD
    Engine Load: 99% Port, 99% STBD
    Fuel Rate: 25.3 GPH Port, 25.3 GPH STBD

    incidentally, the hull was "allegedly" stripped & barrier coated in 2016.
  7. Capt J

    Capt J Senior Member

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    What was speed at WOT?
  8. dscaring

    dscaring New Member

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    Oh yeah sorry...and speed was 27.3 knots per the GPS
  9. Capt Ralph

    Capt Ralph Senior Member

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    Reminds me to ask, Did anybody compare prop specs (diameter?) to the original spec?