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Boat weight?

Discussion in 'Catalina 310' started by marchem, Oct 9, 2017. Add this thread to a FAQ

  1. marchem

    marchem

    Joined Nov 16, 2012
    425 posts, 14 likes
    Catalina 310, 2000, #31
    US Santa Cruz, CA Santa Cruz
    We hauled our boat today for a bottom job. The weight readout on the lift was 16,000 lbs. Someone said that that is an overestimate, because of the angle of the slings, and that 14-14.5K lbs was closer to correct.

    The spec for the displacement is only 10,300 lbs. I know we've put a lot of stuff on the boat, but 4,000 lbs? Seems excessive. Or maybe the spec is low, and the travel lift reads high?

    What sort of readings do others get? Just curious.
     


  2. jssailem

    jssailem

    Joined Oct 22, 2014
    3,190 posts, 592 likes
    CAL 35 Cruiser
    US Salem, Moored Port Everett WA
    I heard that is what sumo wrestlers say at weigh in.
     


  3. shemandr

    shemandr

    Joined Jan 1, 2006
    2,868 posts, 209 likes
    Marblehead Skiff 14'
    US Greenport, NY Greenport, NY
    That's almost an extra keel! Time for a diet. Take everything off - all of it. Put back only what you actually use. Your boat is in the water all year? Maybe run a dehumidifier for a few days with the cabin closed up. You'll suck
    out a few hundred pounds.
    "Or maybe the spec is low, and the travel lift reads high?"
    That's pretty much what I say every morning when I weigh myself.
     


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  4. Meriachee

    Meriachee

    Joined Aug 1, 2011
    1,845 posts, 297 likes
    Catalina 270
    CA Edmonton, Ab Wabamun - on the orange ball
    Gravity doesn’t change at an angle. Either the gauge was out of whack, or the boat is that heavy.
    They don’t charge the lift by pounds? Kinda like the grocery store spraying the broccoli every 87 seconds and then charging the weight.
     


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  5. vhoisington

    vhoisington

    Joined Mar 13, 2011
    123 posts, 22 likes
    Islander Freeport 41
    US Longmont, CO (SF Bay) Longmont
    Well add in the weight of existing fuel, water and waste tanks (water weights about 7.62 lbs per gallon, diesel is a little less and holding tanks are the same as water weight) all electronics, sails, etc and you might be surprised.

    But yes, this does sound a little high for your boat
     


  6. marchem

    marchem

    Joined Nov 16, 2012
    425 posts, 14 likes
    Catalina 310, 2000, #31
    US Santa Cruz, CA Santa Cruz
    They charge by the foot...
     


  7. rpwillia

    rpwillia

    Joined Sep 29, 2008
    1,697 posts, 7 likes
    Catalina 310 #185
    US Quantico
    At haul out a few ago a crane operator I trust told me 15,500. I need to paint it in vertical stripes as they are slimming.
     


    marchem likes this.
  8. marchem

    marchem

    Joined Nov 16, 2012
    425 posts, 14 likes
    Catalina 310, 2000, #31
    US Santa Cruz, CA Santa Cruz
    That makes me feel better!!!
     


  9. marchem

    marchem

    Joined Nov 16, 2012
    425 posts, 14 likes
    Catalina 310, 2000, #31
    US Santa Cruz, CA Santa Cruz
    Actually the angle does matter. If the straps are pulling at a 45 degree angle the load (which is being measured) is much more than the actual weight. At 90 degrees the load becomes essentially infinite.
     


  10. Ron20324

    Ron20324

    Joined Jan 22, 2008
    5,556 posts, 352 likes
    Beneteau 323
    US Annapolis MD
    My B323, 32'10", for several haulouts is 13,000. It's pretty well equipped.
     


  11. Meriachee

    Meriachee

    Joined Aug 1, 2011
    1,845 posts, 297 likes
    Catalina 270
    CA Edmonton, Ab Wabamun - on the orange ball
    Really? A pound is a pound is a pound. If you're going to tell us that the straps in the travellift were at a 45 degree angle, I would think that you'd be a lot more concerned about the security of the load (your boat) than the weight.
     


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  12. JamesG161

    JamesG161

    Joined Feb 14, 2014
    1,800 posts, 247 likes
    Hunter 430
    US Waveland, MS
    Hold the horses...
    Almost all big weighing scales, fork lifts, cranes, etc. use "strain cells" and are good to maybe 3 digits of precision.
    So to make a lift safely, all crane lift points have a strain cell and are SUMMED for Total Weight.

    If that is NOT true, stop using that lift. UNSAFE!!!:yikes:

    If that lift has not recently calibrated their strain cells [by license and law they must]
    Lookout boat!

    ANGLE of the straps has ZERO to do with total weight. However the Angle of lift, of a single boom crane, is key to prevent "tipping".

    If those strains cell said 16,000 lbs and they were calibrated correct, then your boat weight is 16k ±1k precision.
    ______
    Trivia: Fresh water at room temperature weighs ≈8.33 lbs/gallon. Good marine diesel is ≈ 7.1 lbs/ gallon
    Crap diesel is heavier ≈7.9 lbs/gallon . You grade diesel by its specific gravity at 15.6 C°.

    Jim...

    PS: Diesel is lighter than water, doesn't mix with water and it Floats on water. ;)
     


    Parsons likes this.
  13. Meriachee

    Meriachee

    Joined Aug 1, 2011
    1,845 posts, 297 likes
    Catalina 270
    CA Edmonton, Ab Wabamun - on the orange ball
    Not to mention that if the boat gets heavier when it’s angle off vertical increases, how much heel would be required to send it to the bottom?
    :)
     


  14. JamesG161

    JamesG161

    Joined Feb 14, 2014
    1,800 posts, 247 likes
    Hunter 430
    US Waveland, MS
    Quit eating so much Lasagna!!:laugh:

    I stopped weighing in morning and eat more spaghetti!;)
    Jim...

    PS: Quit using your wife's Birthday party as an excuse.:cowbell:
     


  15. Ralph Johnstone

    Ralph Johnstone

    Joined Jan 4, 2006
    2,374 posts, 219 likes
    Hunter H-310
    CA West Vancouver, B.C.
    I believe the mass of the boat becomes infinite only as it approaches the speed of light.

    speed of light.jpg
     


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  16. vhoisington

    vhoisington

    Joined Mar 13, 2011
    123 posts, 22 likes
    Islander Freeport 41
    US Longmont, CO (SF Bay) Longmont
    Thanks for the correction on my weights. I keep mixing diesel and water. No wonder I have engine issues (not really but I do want to note the correction on my misinformation)
     


  17. JamesG161

    JamesG161

    Joined Feb 14, 2014
    1,800 posts, 247 likes
    Hunter 430
    US Waveland, MS
    OMG:doh:
    Make a note to self....:banghead:
    "Don't make a strong case on SBO without 2 cups of coffee"

    Boat Displacement Weight is NOT Total weight of the boat!

    Displacement weight = Weight of Water Displaced when the boat is....

    Floating!!

    Whew! Boat lift is probably safe.
    Jim...

    PS: Fat floats.;)
     


  18. marchem

    marchem

    Joined Nov 16, 2012
    425 posts, 14 likes
    Catalina 310, 2000, #31
    US Santa Cruz, CA Santa Cruz
    The load gets huge, but the mass stays the same, as long as it moves slowly. :)
     


  19. JamesG161

    JamesG161

    Joined Feb 14, 2014
    1,800 posts, 247 likes
    Hunter 430
    US Waveland, MS
    Captain Kirk to Sulu: Warp 2 Mr. Sulu...
    Mr Sulu: But Captain won't we go to infinite mass at 4 times the speed of light?
    Captain Kirk to Mr Sulu: Remember your training? Warp drives bend space thus avoiding relativity mass.:rolleyes:
    Captain Kirk to Log: Remind me to beam Mr. Sulu to the next Class M planet, first!

    Jim...
     


  20. marchem

    marchem

    Joined Nov 16, 2012
    425 posts, 14 likes
    Catalina 310, 2000, #31
    US Santa Cruz, CA Santa Cruz
    https://en.wikipedia.org/wiki/Displacement_(ship)

    Actually, displacement weight is the total weight of the boat...

    Boat lift is safe in ether case.
     



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