Results 1 to 31 of 31

Thread: Lift points

  1. #1
    Join Date
    Nov 2020
    Location
    Springfield, VT USA
    Posts
    15

    Arrow Lift points

    1957 Lyman Runabout 15" recommended lift point with outboard attached.

  2. #2
    Join Date
    Jun 2000
    Location
    Pleasant Valley NS Canada
    Posts
    21,964

    Default Re: Lift points

    Single lift point?
    Hope for the best, but plan for the worst.

  3. #3
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    18,804

    Default Re: Lift points

    One of those eyebolts that screw into the top of the flywheel...be my first choice.
    Lift the engine, boat will follow. Pick the bow from the tow bolt.
    ...if that is wha cher axing

  4. #4
    Join Date
    Apr 1999
    Location
    Hyannis, MA, USA
    Posts
    49,609

    Default Re: Lift points

    Most uses get the boat in and out by trailer. Have see some marinas that provide dry storage on racks, in and out by specialized fork lift. Some especially grand places have a roof and walls and a lift to get the boat out.

    If you feel you must lift by crane and don't trust slings, or if you're thinking of building davits so you can carry it on your 100' motor yacht, start by knowing the loading weight at bow and stern. If no scale big enough, make an 11' lever (so you can have 10:1 multiplier) and pry the boat up a little. A first class or second lever will work and you can press the lever holding a scale to see how much force it takes to more her.

    Most Runabouts have a towing eye just above the waterline. Check that it's in good condition, properly bolted through the stem, and robust enough to take the load plus a generous safety factor. It would make sense to make a lift sling here so it can embrace the bow. Padding required.

    For the stern, eyes through the transom as far out as makes sense, maybe half way up, with decent length chainplates so the strain does not split the transom. Bolted and backed.

    And how's this for the Mothership:

    Last edited by Ian McColgin; 11-25-2020 at 11:04 AM.

  5. #5
    Join Date
    May 2000
    Location
    Conway, MA
    Posts
    5,949

    Default Re: Lift points

    The problem with the towing eye besides it's low position is it is set for tension not sheer, using it to lift up would tend to split the stem. Lifting eyes at the bow would normally be placed in the middle of the fore deck, like the mooring cleat, but connected through the keel at the base of the stem. At the stern, lifting the transom with a bridle between two high through eye bolts would lift the engine and the hull.

  6. #6
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    18,804

    Default Re: Lift points

    Yes, but a 15 foot ob boat should weigh very little in the bow .Not like an inboard boat .

  7. #7
    Join Date
    May 2000
    Location
    Conway, MA
    Posts
    5,949

    Default Re: Lift points

    Might almost balance on the transom? With some outboards it might, almost.

  8. #8
    Join Date
    Apr 2009
    Location
    Mountain lakes of Vermont
    Posts
    15,599

    Default Re: Lift points

    You're only about 45 minutes from me.
    In non-Covid times, I'd offer to come over and help out with whatever you've got going on.
    Perhaps next summer!
    I was born on a wooden boat that I built myself.

  9. #9
    Join Date
    Nov 2020
    Location
    Springfield, VT USA
    Posts
    15

    Thumbs up Re: Lift points

    Quote Originally Posted by Rich Jones View Post
    You're only about 45 minutes from me.
    In non-Covid times, I'd offer to come over and help out with whatever you've got going on.
    Perhaps next summer!
    Thanks Rich, where are you located?
    I am planning on painting the hull and repairing some damage on the forekeel in the spring, so getting it off the trailer would be very helpful.
    I am a newbie with wooden boats and would greatly appreciate any guidance you can offer.
    Thanks

  10. #10
    Join Date
    Nov 2006
    Location
    Winnipeg, Manitoba, Canada
    Posts
    872

    Default Re: Lift points

    gantry made of wood 2.jpgGantry made of wood 3.jpggantry made of wood.jpggantries and slings with photos saved from the net over time (from this forum if I am not mistaken)
    Last edited by oldsub86; 11-26-2020 at 10:03 AM. Reason: added photos

  11. #11
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    18,804

    Default Re: Lift points

    msidd, yer just trying to get her off the trailer?
    Drop the trailer tongue to the ground, (this will lift the stern),block up /or tie up the boat stern /engine where it is at.
    Lift the trailer tongue with the screw or a jack, (this will seperate the sten of the boat from the blocking).
    Tie the bow up to a rafter or a crossbeam between the bow and tongue,which is probably very light,...release the tie between bow eye and trailer winch...voila...pull the trailer out from the suspended boat .
    bruce

  12. #12
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    37,530

    Default Re: Lift points

    Good to see another woodchuck on the forum - welcome! I'm just northeast of Burlington.

    Bruce's suggestion is a good one.

    A single lift point would be tough. Chris Crafts have 2 - but that's on inboards. A friend who has a Thompson that's similar to your boat used 2 straps hooked to comealongs. If using this method, be sure to put a spreader between the sides of the straps so the hull does not get crushed. Also make sure the upper attachment points are strong enough!
    "If it ain't broke, you're not trying." - Red Green

  13. #13
    Join Date
    Nov 2020
    Location
    Springfield, VT USA
    Posts
    15

    Default Re: Lift points

    Thanks Wizbang, oldsub86 and Garret, and Rich
    Among other things I am a timber frame builder so I know how to lift and move heavy wood objects.
    Yum Runner is temporarily housed in a timber frame garage. My intuitive inclination was to use straps, spreaders and the building as structure to lift it off the trailer.
    Once off the trailer I need to block it. I plan on blocking under the transom and the forekeel. Keeping the contact as small a footprint as possible so I can repair and paint the hull. After paint and repair, lift again with the straps and paint the area that was missed. Please correct me if this is not a good plan.
    Thanks so much
    Mitch

  14. #14
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    18,804

    Default Re: Lift points

    Yes it's a good plan...for a 2 ton 25 footer.
    Can we get photos of her and the trailer?

  15. #15
    Join Date
    May 2000
    Location
    Conway, MA
    Posts
    5,949

    Default Re: Lift points

    And the building.

  16. #16
    Join Date
    Jun 2000
    Location
    Pleasant Valley NS Canada
    Posts
    21,964

    Default Re: Lift points

    I'll stick my neck out and suggest that the boat & motor combined weigh less than 1500 lbs,, and not more than 2000. Centre of gravity will be 2 - 3 feet forward of the transom. Put a strap under the hull one foot forward of the trransom and one around midships or a foot farther forward (both straps in line with transverse structure such a s a bulkhead or frame, if possible) and you will be good to go. Remember that the straps won't slide across the hull very easily, so a high lift will start to roll the hull up toward the lifting side.

    For ease of access to work on the hull, I would consider setting the hull on blocks at the keel only, and cross-brace from the inwale to building structure to keep it in place. this will give complete access to the hull along its entire length. For safety when working underneath, put blocking on both sides around midships, adjusted to fit with shallow-angle wood wedges, These can be easily re-positioned when they get in the way.
    Last edited by mmd; 11-27-2020 at 09:57 AM.
    Hope for the best, but plan for the worst.

  17. #17
    Join Date
    Nov 2020
    Location
    Springfield, VT USA
    Posts
    15

    Default Re: Lift points

    Thanks All.
    MMD is pretty right on about the weight. I have a portable gantry to place just forward of the transom, no need for a spreader. Blocking just under the keel will take all of the weight?
    Here is a funny: Dreamed last night that I rolled her over like G&B Marine Railway did to Jonathan Edwards the "Elisa Lee"!! LOL

  18. #18
    Join Date
    May 2000
    Location
    Conway, MA
    Posts
    5,949

    Default Re: Lift points

    How the mind keeps working!

  19. #19
    Join Date
    Nov 2020
    Location
    Springfield, VT USA
    Posts
    15

    Default Re: Lift points

    yum runner.jpgooops, forgot to attach a photo per request from Wizbang 13.

  20. #20
    Join Date
    Nov 2020
    Location
    Springfield, VT USA
    Posts
    15

    Default Re: Lift points

    Tell. me about it! sometimes a burden

  21. #21
    Join Date
    May 2010
    Location
    Chicago
    Posts
    761

    Default Re: Lift points

    fwiw, industrial lifting straps are not much $ at Grainger, and can be had at loads more than you will never need. Empirical process: with the boat in the water under a crane, lift it just clear of the water and adjust the straps until you find the balance point, if something goes wrong, there will be a splash and no more. If you want to weigh it, rent a dynamometer or make friends with someone who does rock-and-roll truss rigging. The things nowadays broadcast weight by wifi and are only a bit larger than a shackle. My mackinaw weighed 3340 with water ballast empty. The red thing in the photo is a load cell I was able to borrow that was good for 10 tons. Once you find the balance point, talk to people with some engineering chops and put in the lift points.

    Ken
    IMG_8558.jpg

  22. #22
    Join Date
    Jun 2000
    Location
    Pleasant Valley NS Canada
    Posts
    21,964

    Default Re: Lift points

    Some time ago I posted a method for calculating the weight of a boat on its trailer using a tape measure and bathroom scales. No rentals or cranes involved.
    Hope for the best, but plan for the worst.

  23. #23
    Join Date
    May 2010
    Location
    Chicago
    Posts
    761

    Default Re: Lift points

    Quote Originally Posted by mmd View Post
    Some time ago I posted a method for calculating the weight of a boat on its trailer using a tape measure and bathroom scales. No rentals or cranes involved.
    seriously, send me the link. there isn't any pick point on my boat that I can think of but it would mash a bathroom scale

    Ken

  24. #24
    Join Date
    Nov 2006
    Location
    Winnipeg, Manitoba, Canada
    Posts
    872

    Default Re: Lift points

    Borrowed from another web site:

    Here is the method I use to weigh boats on a trailer without hauling the boat to a commercial scale, which requires two trips for boat and trailer.

    It's simple, accurate and will cause bystanders to marvel at your engineering whiz.
    The boat stays on the trailer the entire time. Put the scale under the tongue near the end. You can even put a block on the scale to lift the tongue so you can see the dial. Record the weight. Now, slide the boat aft on the trailer 12" to 18". You must measure exactly how many inches you moved it, and record that. With the scale in the same location under the tongue, record the new scale reading. Finally, measure the distance in inches between the trailer axle (wheel centerline) and the point on the tongue where it touches the scale. You have then four measurements:
    W1 = first (heavier) scale reading in lbs, W2 = second scale reading in lbs, X = the distance you shifted the boat in inches, C = distance between trailer axle and scale point in inches.
    The formula is Boat Weight = C (W1-W2)/X
    A couple of notes. The result, like any measurement, is sensitive to the accuracy of the input data. In this case, the most critical is the distance you slide the boat. One inch error out of 12 inches will really make a difference in the result. Slide the boat as far as you can and still have a readable load on the scales. Notice, too, that by subtracting the two scale readings, any constant error in the scale is canceled out.
    Note to techies: The formula was derived by taking the sum of the moments around the trailer axle for each case and (since the sum of moments about a stationary object is zero) set the two equations equal to each other and solve for the trailer weight. Things that you don't know, like the trailer's weight and the location of the boat's center of gravity cancel out, leaving just the variables that you can measure, and the boat weight.
    I also use another version of this formula for weighing a boat while it is under construction so I don't get a bad surprise when it's finished. You can use two bridged scales and/or a trailer extension to increase the range of weights you can measure. I usually shoot for measurements of about 30-40lbs
    for a low end and 250lbs or so for the high end.

    In your case I would reverse the order of moving the boat and do it when you next go to the launch ramp so you can move the boat in a partial launch.

  25. #25
    Join Date
    Jun 2000
    Location
    Pleasant Valley NS Canada
    Posts
    21,964

    Default Re: Lift points

    oldsub86 has it. I couldn't find my WBF posting I referred to above, but I did find the original MS Word document in my files. To reiterate what oldsub86 has posted above:


    Weighing a boat on a trailer


    Shift the boat as far forward on the trailer as it will go.

    Place a scale under the tongue support leg. Record the weight.

    Measure the distance from the tongue support leg to the tip of the boat bow. Record this.

    Shift the boat aft on the trailer a couple of feet, but not so far as to allow the trailer to tip backwards.

    Place a scale under the tongue support leg. Record the weight.

    Measure the distance from the tongue support leg to the tip of the boat bow. Record this.

    Measure the distance from the tongue support leg to the centre of the trailer axle (if a twin-axle trailer, measure to the point exactly half-way between the axles). Record this.

    Calculate the boat weight using the following formula:

    W = C(W1-W2)/X

    Where:
    W = weight of boat
    C = distance between tongue support leg and centre of trailer axle(s)
    W1 = first (heavier) scale reading
    W2 = second (lighter) scale reading
    X = distance boat was shifted between scale readings
    Hope for the best, but plan for the worst.

  26. #26
    Join Date
    Oct 2014
    Location
    SW Washington/ At Sea
    Posts
    470

    Default Re: Lift points

    Great advice here so far! I use the outboard to lift the aft end of smaller skiffs/runabouts. I have one of those motor locks that slides over the securing screw handles, it forms a cleat. The bracket that holds the motor to the transom is very strong and makes a good lift point.

  27. #27
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    21,414

    Default Re: Lift points

    Erring on side of caution, given that my point of view is not standing beside you and your specific boat, I am going to humbly suggest you want to lift an older, lightly-built wood boat from underneath. That probably means straps suspended from a block and fall for a DIY application. But it could also mean blocking or a cradle jacked up incrementally. Would help to know why you need to lift it and how often you need to do so.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  28. #28
    Join Date
    May 2010
    Location
    Chicago
    Posts
    761

    Default Re: Lift points

    The process below is really elegant! However it is dubious in my case; the tongue weight is #430, It's really difficult to slide the boat on the trailer unless it's good and slimy with algae, and it's a dual axle trailer, so exactly where is the center point of the suspension system?? All bickering aside, I am definitely going to try it when things warm up to compare with my other figures. Thanks!!

    Ken



    Quote Originally Posted by oldsub86 View Post
    Borrowed from another web site:

    Here is the method I use to weigh boats on a trailer without hauling the boat to a commercial scale, which requires two trips for boat and trailer.

    It's simple, accurate and will cause bystanders to marvel at your engineering whiz.
    The boat stays on the trailer the entire time. Put the scale under the tongue near the end. You can even put a block on the scale to lift the tongue so you can see the dial. Record the weight. Now, slide the boat aft on the trailer 12" to 18". You must measure exactly how many inches you moved it, and record that. With the scale in the same location under the tongue, record the new scale reading. Finally, measure the distance in inches between the trailer axle (wheel centerline) and the point on the tongue where it touches the scale. You have then four measurements:
    W1 = first (heavier) scale reading in lbs, W2 = second scale reading in lbs, X = the distance you shifted the boat in inches, C = distance between trailer axle and scale point in inches.
    The formula is Boat Weight = C (W1-W2)/X
    A couple of notes. The result, like any measurement, is sensitive to the accuracy of the input data. In this case, the most critical is the distance you slide the boat. One inch error out of 12 inches will really make a difference in the result. Slide the boat as far as you can and still have a readable load on the scales. Notice, too, that by subtracting the two scale readings, any constant error in the scale is canceled out.
    Note to techies: The formula was derived by taking the sum of the moments around the trailer axle for each case and (since the sum of moments about a stationary object is zero) set the two equations equal to each other and solve for the trailer weight. Things that you don't know, like the trailer's weight and the location of the boat's center of gravity cancel out, leaving just the variables that you can measure, and the boat weight.
    I also use another version of this formula for weighing a boat while it is under construction so I don't get a bad surprise when it's finished. You can use two bridged scales and/or a trailer extension to increase the range of weights you can measure. I usually shoot for measurements of about 30-40lbs
    for a low end and 250lbs or so for the high end.

    In your case I would reverse the order of moving the boat and do it when you next go to the launch ramp so you can move the boat in a partial launch.

  29. #29
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    37,530

    Default Re: Lift points

    I don't think the trailer/scale method will work with a double axle trailer, as it's counting on a single fulcrum point (the axle in a single axle trailer).
    "If it ain't broke, you're not trying." - Red Green

  30. #30
    Join Date
    Jun 2000
    Location
    Pleasant Valley NS Canada
    Posts
    21,964

    Default Re: Lift points

    Yes, it will work with a double-axle trailer; see my post #25, line 7 of the instructions...
    Hope for the best, but plan for the worst.

  31. #31
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    37,530

    Default Re: Lift points

    Quote Originally Posted by Garret View Post
    I don't think the trailer/scale method will work with a double axle trailer, as it's counting on a single fulcrum point (the axle in a single axle trailer).
    My bad - please see Michael's post.
    "If it ain't broke, you're not trying." - Red Green

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •