http://www.hisse-et-oh.com/articles/article.php?article=760
I made this light, foldable gangway "passarelle", it is surely nowhere near the professionally built ones, but it costs one tenth and looks ok for the job.
The starting point is one of those four-piece foldable ladders, they can be found in prices ranging from 50 to 100 euro. The one I found was sold with a SWL of 120kg in horizontal position with two elements: add an additional element, a bit of rust here and there... with a bit of caution it should still be ok.
First thing is to cut off one of the four elements, I had to unrivet it, other ladders will have to be sewn.
these ladders are usually sold with a stabilizing horizontal bar, which is longer than needed but can be useful to fit the two wheels once it is cut to the appropriate length
the provided fixing bolts have been replaced by two ring bolts, where the lifting rope will be attached.
Then I took two fixed wheels (meaning they cannot rotate freely), there are two things to consider: first their base mounts must fit inside the width of the stabilising bar, which limits the choice to smaller wheels only, then their size must not prevent the ladder to be completely folded once they are fitted
As for planking, I chose the simplest option: plywood. Alternatives were teak planks, aluminum plating, hardwood bars, etc.
I cut the three plates, made holes for the rivets where the aluminum steps are positioned, and those for the transversal wooden anti-slip "sticks".
Once the ladder (now halfway to being a gangway) is folded, two plywood planks will be adjacent one another, so just be careful to position the transversal anti-slip so that the ladder can be fully folded.
general rehearsal with rivets
second rehearsal rivets plus anti-slip sticks
Then followed several coats of paint, riveting the three planks and screwing the anti-slip sticks.
Looks ok doesn't it ?
I hung the gangway horizontally and jumped over it several times and got that "strength" feeling, well we'll see...
One possibility to reduce the bending moment would be to hang the passarelle attaching the lifting ropes at the end of the second element, instead of at the end
once it is folded it can be put inside a locker, or discreetely on the side of the cockpit, very approximate measurements are 85x35x20cm
In order to still be able to use the now-gangway as a ladder, I thought a possible improvement might be to cut staggered half-moon shaped holes on the planks, where the aluminum steps are placed, like I tried to show on the unexcusably horrid picture below; unfortunately the minimum dimensions of the holes would be too risky for the tiny feet of my daughters (the younger one has a 21 size, that makes a foot barely longer than 10cm) so I just abandoned the idea. And oh yes, the spacing between the anti-slip sticks is maybe too tight for an adult, still I had to make it like that...
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