How do I get boat off trailer?

Discussion in 'Boatbuilding' started by series60, Aug 19, 2009.

  1. Fanie
    Joined: Oct 2007
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    Location: Colonial "Sick Africa"

    Fanie Fanie

    Hi Owene,

    I heard that one before :D I guess news travel fast. At least the guy was quick to get away from the dry. I also feel like that currently, getting very land sick (sick of sitting on land).
     
  2. Safety First
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    Safety First Junior Member

    FYI, the ABYC states that the Bow Eye be constructed and installed to withstand twice the Gross weight of the boat in a direct tension pull... along with other specifications. It would be rare to find any boat with a bow eye mounted on a truly vertical plane to allow for the Bow Eye to be perpendicular to the bow plane while its being towed on absolutely flat calm seas for a direct tension pull to be employed. It is more likely that the Tension forces are shared with sheer and torsional stresses and that is why I believe that it is engineered to withstand the amount of tension that the ABYC states. If in fact a boat did weigh 2 tons, 4000 lbs, and if a boat is supported by boat stands under the transom, and if in fact there was half the weight of the boat at the Bow Eye, which would be 2000 lbs. The weight at the Bow Eye is usually substantially less than half the weight of the boat. Imagine the stress applied to a bow eye while a boat is being towed in 2 to 5 foot seas. Imagine the acceleration that occurs when the tow boat is going faster and then slower than the boat being towed. Have you ever towed a car with a chain and you slow down and the car behind you doesn't so you quickly give it the gas and the slack in the chain now jerks tight and puts a great amount of stress on both attachment points? The same thing happens to the Bow Eye of the towed boat. Although the Bow Eye is not defined or designed to be a lifting point, which is intended to raise the entire boat from along with other fixed lifting points, it is engineered as previously described which can be calculated into your usage of the Portable Boat Lift as it applies to your boat. There is in fact engineering involved in span tables of Lumber regarding its ability to withstand certain stresses depending on many factors such as size, species, and so on; The same way, there are also codes and engineering to determine the span for these manufactured or naturally milled wooden members. There are also codes and engineering that apply to the manufacture of steel structural components.
    There is no engineering available for the sizing and/or any other criteria for a "Tree Branch" and you'd be wise to never go under any load supported by a Tree Limb. As a kid I was always surprised when the bough broke.
    I would confidently suggest that the bough would more likely break before the "Bow" does.
    Take a look at www.portableboatlift.net and see if the engineering and fabrication don't in fact take the difficult task of separating boats from trailers and make much more sense than using a tree limb and/or getting under boats to inch them out with dunnage, bottle and floor jacks.
     
  3. Commuter Boats
    Joined: Oct 2006
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    Location: Southeast Alaska

    Commuter Boats Commuter Boats

    "series60 " got his boat off the trailer, there was discussion about bow eye strengths ( which are listed in the catalog) and then some discussion about ABYC and engineering tables for wood. This chart may not be relevant but I hope some will find it interesting.
     

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  4. alan white
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    alan white Senior Member

    Interesting to see this thread come alive just when I was about to build my own design for transferring a boat from trailer to stands/cradle and back again.
    I too do not believe the bow eye is on average up to being stressed as seen in the ad for the boat lift above. One reason is that there's a tremendous lateral load on the fitting, which is often no more than 3/8" in diameter on a 2000 lb boat. The stress will possibly bend the eye bolt and effectively loosen it as well. Also, with the bow eye lifting method, two well-spaced stern stands are needed while a sling arrangement requires only one. Add to this the fact that no two boats are alike in bow angle and what I see is a bunch of lift manufacturers selling a product that would have to be more sophisticated and expensive to lift the boat properly---- in slings or rather one sling, which distributes the load safely every time.
    The bow eye is designed for a straight-line pull to load the boat on the trailer. Even then, there's generally some angle involved. I wouldn't tow a boat with it. I would use a bridle through chocks to the deck cleat. Easier to rig and quickly release.
    My transfer system would use a sling, an over-the-top spreader, and two tall tripods, and one or two (depending on the boat design) jack stands at the stern.
    This setup will be fast to set up and it will reliably raise any boat without any chance of damage to fittings.
     
  5. SafetyFirst
    Joined: Jan 2010
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    Location: Florida

    SafetyFirst New Member

    Portable Boat Lift

    If you're like me you have tried any number of ways to separate your boat from your trailer to service the trailer or the boat hull. I have used a product by Portable Boat Lift that allows one person to safely separate their boat from their trailer in minutes, anywhere. They can be found at www.portableboatlift.com
     
  6. Red Tide
    Joined: Sep 2009
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    Red Tide Junior Member

  7. Safety First
    Joined: Nov 2009
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    Location: Florida

    Safety First Junior Member

    YardArms

    Yardarms are pretty heavy duty but mostly heavy, about 350lbs each and you need four of them. Not very portable but yes heavy duty. Portable Boat Lift has 3 main components each weighing about 75 lbs. It's a lot easier to use, a lot lighter, and a whole lot less money, you're right.
     
  8. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Why don't you run some paid advertising rather then smooching up free space here? Self promotion is a fairly easy thing, but that's not what this arena is about.

    I find your contraption an expensive contrivance. Any boat lift that need other equipment just to help with the lift, isn't a boat lift. It's overly complex for what it is and incomplete to say the least, perticularly at the current asking price.

    Any one that regularly needs to remove a boat or boats from trailers can rig up a lift from cobbled together boat winches and straps, likely for considerably less then your setup.

    My lift is home made, handles 5 tons and is operated by a single 1 HP motor. I think I have about 1,000 bucks invested in it. It works just like thousands of boat house lifts do.
     
  9. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    I take boats off by backing fast and slamming on the brakes with the winch cable having some slack. Then put jacks or large styrofoam blocks on the corners and let the boat down.
     
  10. Safety First
    Joined: Nov 2009
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    Safety First Junior Member

    I'll stop here and I will not reply to any more replies to my posts. No more smooching. I don't care if you like it or hate it, it was for informational purposes only. My reason for posting was to offer just one way to help with the arduous task. Jack stands did not come with the floor jack I bought, but I purchased them as I needed them to use with the floor jack. I will use Timber Blocks but will not use cinder blocks. Jack Stands are simply easier and better for me as they are adjustable and rated. I contacted a boat stand manufacturer and they walked me through what type, how many, and the placement of their boat stands for my particular boat. I don't believe in cobbling, to make or put together roughly or hastily, when it comes to lifting my boat or that can affect my health or safety. I am not here to put anyone off, argue, or purport the Portable Boat Lift is the only way, it simply works well for me.
     
  11. DianneB
    Joined: Jan 2010
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    DianneB Junior Member

    A long time ago when I hauled my 2.5 ton inboard cruiser home for the winter (on a big roller trailer) we tied off the stern to a stake driven into the ground, moved the trailer ahead a few feet, put blocking in place, moved the trailer a bit more, more block, and so forth until she was standing proud on the blocks. Worked fine as a one-man (one woman?) job without any cost and without any sweat.
     
  12. alan white
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    alan white Senior Member

    Now put it back on.
     
  13. Frosty

    Frosty Previous Member

    Some things need saying twice.
     
  14. alan white
    Joined: Mar 2007
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    Location: maine

    alan white Senior Member

    Anyhow, I've got this Rhodes 19 with the short fin keel and a couple of other keel boats. Like a lot of boats I transfer, it isn't a trailer-launched boat. But it does move around on a trailer.
     

  15. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Most small craft can be handled with a chain fall, come-along or hefty *** winch, dangling from a handy tree branch. I have several chains around branches in my yard and use them frequently as it easier. If I had a paved lot, I used a rolling gantry that I've made. But with the sugar sand and roots yard that I have, it just lives in front of the barn where it belongs and tools are handy.

    A small, light weight gantry is a fairly easy thing to make, especially if you can weld, though it could bolt together too. The first one I made was wood and it could hoist a couple of tons, but it moaned and bitched about it the whole time, making me nervous and eventually cracking. I've made a few since, most from square and rectangular tubing and some very simple chain driven drive systems to hoist straps, hooks or and elevator.

    A gin pole is even easier, though the boat will swing unless contained with lines or straps. On a budget, I'd use a gin pole, a trailer winch and some tackle to multiply power if necessary. You can snatch just about anything up off anything with a gin pole. Of course it's not portable, but it can be swung through a radius.
     
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