single point lift |
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Virginia H.
Crew Joined: 03 March 2012 Location: Hampton, Va Status: Offline Points: 46 |
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Posted: 03 March 2012 at 9:08pm |
In all of the discussions I have not seen anything on a single point lift for the Laser 28. Is it standard and if not has anyone added one successfully. Our yacht club has an i beam crane set up for single point lift like for a J24.
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frfletch
Commodore Joined: 13 May 2008 Location: Canada Status: Offline Points: 365 |
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Many of us use a single point lift. My boat is stored on the hardstand and we use the lift regularly.
A stainless steel bracket with a 1/2" ss pin is mounted permanently to the rear two keel bolts. Then you install an inspection port in the coachtop with its center 1075mm forward of the main cockpit bulk head measuring from the cockpit side. Order or buy a lifting strap with a minimum length of 7 1/2'. The strap is fixed to the bracket with the 1/2" pin and leads out of the new inspection port and to the lifting hook. The port is about 22" aft of the CG so two retaining lines are used to hold it back. Mine are 5/16" amsteel with a loop at each end. Slip these over the strap before fixing the strap to the hook, then each of the amsteel lines is led 2 times around the coachtop winch and then it just loops over the primary winch drums each side of the cockpit. Key issue is to get the exact length of the two retaining lines correct so that when the hook rises and the strap takes up the weight of the boat, the strap finds center of the inspection hatch. I installed a 4" inspection hatch and have no problems with this method. We just set up the system, fix the hook, leave the boat and lift. I can provide the exact length of the retaining lines for you after this weekend. I think Bill Layton can either provide you with the keel bracket, or provide a drawing for you to have one made. They are very simple. |
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Virginia H.
Crew Joined: 03 March 2012 Location: Hampton, Va Status: Offline Points: 46 |
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Thank you.
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frfletch
Commodore Joined: 13 May 2008 Location: Canada Status: Offline Points: 365 |
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Just to correct yesterday's post, the keel bracket is actually attached to only one of the larger keel bolts within the keel well. The length of the two retaining lines that you will make using 5/16 (8mm) Amsteel is 93 5/8" to the inside of the end loops when they are stretched out with medium tension. To measure tie one end of a piece of small cord (1/8") around a fixed object and the other end through the first loop you make that will go over the lifting strap. (I was on the boat so I tied it to the lower shroud). Then splice a much larger loop on the other end of the Amsteel retaining strap using a straight slip splice and lead the end fid core out of the core center 12" down so that you have the end of the rope outside the area of the slice to allow length adjustments. Then tension the strap between the fixed point and it's opposite end. (I used the winch to wrap the other end of the cord around and pulled it tight by hand to put tension in the new line and measure its length.) If it is short, take off the tension and shorten it a little by slipping the butt-end of the splice a little pulling to make it shorter, or letting it out to make it longer, then tension the strap and measure again. When the length is correct, whip the adjustable splice, but don't lock stitch it yet. Now test it with a small trial lift. Lead the lifting strap from the bracket out of the inspection port, slipping the little looped ends of the retaining straps around the lifting strap, and tie the lifting strap to the boom with a piece of bungee cord to keep it in the "up" position. Now lead the two retaining lines around the cabin top winches two times clockwise, and then place the larger loop over the top of the genoa winch on each side of the boat. At this point the lifting strap will be pulled hard against the rear of the inspection port. Don't worry about that. Loop the lifting strap's end over the lifting hook and start lifting observing that the strap should center of the port when the boat is lifted. If it does not center.......read below:
Since you have not yet cut-off the final butt-ends used to make the slip splice on the bigger looped end, you can still slip these one way or the other to make the final adjustment to the length of these straps. When everything centers perfectly in the lift, then lock stitch both splices and you are done. We have done over a hundred launches using this method and it has proven to be fast and reliable. It provides a perfect lift every time without any adjustments and in the 3 years we have been using this set-up we have never re-adjust the length of the retaining lines which simply do not stretch under these tensions. One might think one could use a bowline on each end of the rope and adjust those, (maybe one could) but fine tuning line length using a knot would be difficult. Also, these retaining lines do come under quite a bit of tension, and a bowline will break any line or rope at about 50% of its designed working load, so I prefer the simple slip splice using a long tail led inside the core of the braid. My tails go down the core about 12" and are lock stitched for a considerable about of that length. Last note: My coach top winches are Harken #8 and my primaries are the original Maxwells. If your winch drum barrel circumferences are different than those, then your lines may have to be slightly adjusted in length. Just try to get the second loop close to the 93 5/8" figure with an extra large loop on that end so that if it has to be shortened it will still fit around the top of the big winch. Good Luck! |
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Virginia H.
Crew Joined: 03 March 2012 Location: Hampton, Va Status: Offline Points: 46 |
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could you email me the drawing of the bracket? I assume the largest aft keel bolt? My email address is armst1111@aol.com, Thank you.
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frfletch
Commodore Joined: 13 May 2008 Location: Canada Status: Offline Points: 365 |
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I am headed to the boat now and will measure and photograph it for you. Additionally, I think that Bill Layton may have them and can be contacted via this post. They are a very simple thing.
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frfletch
Commodore Joined: 13 May 2008 Location: Canada Status: Offline Points: 365 |
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Do you have an inspection port in the deck through which the lifting strap must pass? If not, you will need to cut one in and go through the procedures of mounting the little hatch and hatch cover. I think I may still have the diagram on this that Bill sent to me, but if not, no doubt he will pick up on this post and respond.
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Virginia H.
Crew Joined: 03 March 2012 Location: Hampton, Va Status: Offline Points: 46 |
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I have a hole over the 2 aft keel bolts in the keel sump. It must have been a ventilator at one time.
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