How to build a retractable ladder
A few years ago a friend asked if I had ever made a ladder to get back in the raft. I had thought about one but I am athletic enough to pull myself in the boat so I had not ever gone through the effort to make a ladder. He said he had tried but it did not work. I asked him to bring me the parts and I would mess with it. I tried a couple ideas but they were unsuccessful. After a trip to Ace and looking in every drawer there I came up with this.
Iíve made a few since the first one because I have never come home from a trip with it. Someone always wants it so donít give in or you will have to make another one!
There have been a few posts about these and since they are apparently no longer available so I thought I would post what I have made.
They are kind of a pain to build because there are a lot of steps and it takes some tinkering but here is my ladder. By the way this is a repair to my ladder. The bungee came out and needed fixed. I tried to not sew it the first time but it failed on a trip. My wife and kids love this thing because it makes getting back into the boat after a swim so easy.
You will need 1-1/2" PVC pipe
4 or 6 1-1/2"End Caps
1/4" rod brass or stainless would be best
1/8" bungee cord
1/8" dyneema or Kevlar single braid line
3/32" wire rope end crimps
stainless steel wire or hog rings
dental floss or nylon thread and a needle
a fid or chopstick
2 to 4 packages of sliding screen door replacement roller assemblies.
First off you will need a piece of 1.5Ē PVC pipe 17 inches long for each rung. The top rung is static (I used 1ľĒ for the top rung). The bottom one or two rungs move and have the bungee assembly in them. Drill a 1/4" hole about 1" from each end. The pulleys and brass rod will mound in these holes. Then 2 more holes 90 degrees to those and 1 1/2" from the end. The ropes will slide through these holes or will tie to these.
Cut 2 pieces of 1/4" rod (I used brass because it is what I had around) that fit through the first 2 holes and are the same length as the pipe is wide. They need to sit flush so that the pipe cap can fit on. Use a file if they are a bit long. If there is too much play they may fall out.
The "pulleys" are sliding screen door replacement hardware purchased from a hardware store. I have to ream them out just a touch so that they slide over the 1/4" brass rod. You will need 4 pulleys for each sliding rung.
You will need about 25" of 1/8" bungee cord per side of the ladder and some 1/8" braided Dyneema/Kevlar line. 10 or so feet would be a good starting length for the Dyneema line. I got my Dyneema line from West Marine. I use the Samson rope AmSteel Dyneema AS-78 single braid rope. It is nice to have a bit extra when assembling the ladder
Use a fid or a chopstick and push into the core of the Dyneema line. Remove the chopstick and push the bungee cord into the hole made in the line. Wrapping the end of the bungee with dental floss will make it easier to push through. You can pull it through with the floss too.
Next slide on a 3/32" wire rope crimp so that it covers both the bungee and Dyneema where they overlap.
Stitch the Dyneema and bungee together (I tried not to do this step and that is why I am repairing it). It doesnít take too many passes to secure it.
Flare the strands of Dyneema and then add superglue to both sides of the crimp. The really liquid super glue works the best. The Dyneema is flared so that it can support the weight after it is glued. If you are not crimping it I would probably wrap/sew both ends of the crimp prior to gluing so it will not slip.
After the glue has dried a bit I crimp mine with a set of wire crimpers but I don't know if it helps much. The stitching keeps the bungee from pulling out when it is extended and the super glue keeps the line from pulling out due to your weight.
On the opposite end make a loop in the bungee and use a stainless steel hog ring to crimp it. This loop just needs to fit over the 1/4Ē brass rod.
Make 2 of these assemblies to start, even if you are making 2 retractable rungs.
Now we can start to assemble a rung of the ladder.
Push the brass rod into the first hole, place 2 pulleys from a sliding door and then the bungee. On the other side do the same but make sure the bungee ends up on the opposite side of the pipe.
Fish the Dyneema line to the other side and wrap over the pulley, then back again to the side you started on. You will need to start to stretch the bungee cord as you do this. Get the bungee cord on the other side of the pulley and start the cord going back again. The bungee cord should be sliding over 2 pulleys. Once you have the crimp on the other side of the 2nd pulley the crimp will keep the bungee cord from pulling back again. Now push the cord through the hole 1 1/2 ď from the end of the pipe. You can pull on the cord to make sure it moves. You should have about 15" of movement. Repeat with the bungee on the other side. Be sure not to get the lines/bungees tangled up or crossing too many times inside the pipe.
Now that both bungee cords are through mark them with a sharpie where they come out of the rung of the ladder when they are not pulled tight. You can cut them now but cut them 5 or 6 inches longer than the mark. You can also pull the Dyneema line out and tie a slip knot to keep the line from retracting back into the pipe. If the bungee comes off of the pulleys at this step it can be really difficult to put back on.
If you want a 3 rung ladder repeat the steps above and make another rung.
To finish: Pull out as much Dyneema line as you can from the rung and tie a slip knot in the line near the rung to keep it from retracting. Thread the line through the rung above it and pull it out the side. Place a 1/8Ē stainless steel washer on the line and tie a knot in the line so that it ends near the knot. Repeat on all sides/rungs. You can cut the line a bit shorter if you want now but donít cut it too short in case you need to make adjustments in the future.
For the top rung you can make a loop in the line using your fid or chopstick. Look up on line how to make a loop in braided line or just tie a knot. Knots slip really easy in Kevlar/Dyneema line so be sure to tie a good knot. Make the loop a convenient length so that you can attach it to the boat.
I put traction tape on the rung where your feet go. Take it out side and hang it from a tree or something and test it. I have my kids stand on the rung with me to make sure they wonít break and the knots donít slip. Then put the caps on and make a second one for the other side of the boat! (My friend wants another one now. He got dump trucked on the grand and ended up on the other side of the boat. Canít hurt to have two I guess.)
Sorry about the quality of the pictures tonight. I was in a hurry. Donít get too frustrated with this project!