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Thread: On-trailer Boat Lift

  1. #1
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    Default On-trailer Boat Lift

    This just came thru my feed. Looks interesting. Expensive, but quite amenable to a DIY version, for those who aren't tallying their hours.

    https://www.jamestowndistributors.co...%20Boat%20Lift


  2. #2
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    Default Re: On-trailer Boat Lift

    Some of the smaller boat yards have things like this, bolt on or old popetts welded on.

  3. #3
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    Default Re: On-trailer Boat Lift

    It's $750 for 4 of 'em - so not quite as bad as it first appears. Judging by the colors I'd guess made by Brownell? Their jackstands aren't cheap either. Good quality though.
    "If it ain't broke, you're not trying." - Red Green

  4. #4
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    Default Re: On-trailer Boat Lift

    Yard and transport ( pro) trailers from Brownell have long been fitted with them.

    Helpful. If its just to paint the bottom, consider a pair: paint the aft half; wait an hour; lower the boat and move the stands forward. Or do one side and then the other.

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

  5. #5
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    Default Re: On-trailer Boat Lift

    I use these and find that they work great.

  6. #6
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    Default Re: On-trailer Boat Lift

    These are not lifts. The keel takes the weight and is firmly supported. The poppets simply keep the boat upright. The advantage of adjustable poppets is, of course, that it can take a range of boats.

  7. #7
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    Default Re: On-trailer Boat Lift



    Quote Originally Posted by Ian McColgin View Post
    These are not lifts. The keel takes the weight and is firmly supported. The poppets simply keep the boat upright. The advantage of adjustable poppets is, of course, that it can take a range of boats.

    The promotional photo from the maker clearly shows the poppet used to jack-up the boat so that it can be painted.

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

  8. #8
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    Default Re: On-trailer Boat Lift

    Faced with swopping trailers under an old Breton fishing boat, I put up two cross tubes on stands and lifted it with two ratchet straps. I expected to have to jack it up under the keel, then hold it up with the straps, the event, the strap mechanism was strong enough to do it alone.
    Just about to do it again with a GRP 20ft cruiser. Prob a bit heavier, at nearly a tonne, so might need the jack.

  9. #9
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    Default Re: On-trailer Boat Lift

    If you want to jack your boat on the chines, you are welcome to take the risk. The picture goes no where near the keel so can't see if it's supported or not.

    Sometimes a boat hauler will jostle things a bit to get it right, especially fore and aft trim, but even there the boat's pivoting on the keel, not lifted off.

    People do get away with unsafe lifts, especially of lighter vessels. Doesn't mean poppet companies advise unsafe lifts.

  10. #10
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    Default Re: On-trailer Boat Lift

    If you want to jack your boat on the chines, you are welcome to take the risk. The picture goes no where near the keel so can't see if it's supported or not.
    The image shows the hull lifted above the trailer bunk. And the chine is a fine place from which to jack the boat.

    Brownell, the maker, in fact, calls these, "trailer-mounted boat lifts." Their copy explicitly states:

    The Trailer Mounted boat lift mounts securely to your trailer frame. It is designed to safely lift a boat (up to 10,000 pounds) enough to clean or paint the bottom while it rests on the trailer.

    Screen Shot 2021-09-14 at 1.26.33 PM.jpg
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  11. #11
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    Default Re: On-trailer Boat Lift

    RE: Lifting from the chine: I direct your attention to 00:45



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

  12. #12
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    Default Re: On-trailer Boat Lift

    Screw jacks lifting 2500 lbs? Humm. At least they have acme treads.

  13. #13
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    Default Re: On-trailer Boat Lift

    Quote Originally Posted by Andrew2 View Post
    Screw jacks lifting 2500 lbs? Humm. At least they have acme treads.
    I have Brownell jackstands on my boat. The threaded/nut section is identical to these & I've found them to be amazingly strong. I've seen novices lift good sized boats off keel blocks with them.
    "If it ain't broke, you're not trying." - Red Green

  14. #14
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    Default Re: On-trailer Boat Lift

    OK. I'm wrong.

    Lifting on the chine is safe mostly assuming your boat has no major ballast. Like an outboard. In the ad the after poppet is in the center of the panel but let us suppose they know that boat and do not intend the pic as a general jack placement tutorial.

    And let us assume that the instructions note the problems of going too far one jack at a time.

    But for efficient bottom prep and painting, it's hard to beat proper blocking. You know: room to swing a sander . . .

  15. #15
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    Default Re: On-trailer Boat Lift

    Quote Originally Posted by Breakaway View Post




    Not referencing anything Breakaway said... If the boat in this photo is normally supported by the two bunks and the keel, the jacking shown will be lifting it off the keel also. That boat will not be supported at the keel unless there are also jacks under the keel.

    Jeff

  16. #16
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    Default Re: On-trailer Boat Lift

    It doesn't look like it would be too difficult to make a set yourself using scaffolding levelling jacks.

    https://www.menards.com/main/paint/l...5760268&ipos=1

  17. #17
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    Default Re: On-trailer Boat Lift

    Quote Originally Posted by Andrew2 View Post
    Screw jacks lifting 2500 lbs? Humm. At least they have acme treads.


    hold my beer

  18. #18
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    Default Re: On-trailer Boat Lift

    Quote Originally Posted by oldsub86 View Post
    It doesn't look like it would be too difficult to make a set yourself using scaffolding levelling jacks.
    As the owner of both a set of boatstands and a scaffolding tower, you're right. The "tricky" part is cobbling together a good swiveling mechanism to accommodate the hull, the base is pretty self-explanatory.
    Steve

    If you would have a good boat, be a good guy when you build her - honest, careful, patient, strong.
    H.A. Calahan

  19. #19
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    Default Re: On-trailer Boat Lift

    Swiveling mechanism !!! A 40' sloop washed up on the sand just south of the Hyannis Port Yacht Club. The owner had about no money so he resolved to do it alone; no machinery but plenty of Egyptian technology and raw courage. What he had going was all sand and never any waves.

    I did not see how he got the boat pointed towards water or why he decided to go that way rather than stern first. I think you'll guess at the same reason I've hypothesized but I don't know, never talked to him.

    He jacked her up on the keel with stands in line with the jack and tightened regularly. Once an inch above the ambient sand, he'd attach four tall legs rather like what LFH designed for the Marco Polo. These were sloped aft at the back end of rubbing boards and tied both front and back and and X, and tied under as slings. The front were yoked together with a pulley and come-along to an anchor off in the water.

    Pulling easy on the come-along the boat's weight would rock up onto the legs when he'd get the stands out of the way. More pulling past legs straight up and then then boat would fall gently down and forward.

    And repeat many times. He could manage about four cycles per day for a foot's gain. Two months for the thirty or so feet to water's edge and thirty more into deep enough water that she floated free.

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