Mary Skater wrote:
...what I can't work out from the photos is how the bits are held together. Is glue strong enough, or do the parts have to be screwed or riveted together?
PVC connects by either threaded fittings or "slip" fittings, depending on your application or preference. Here, Gill elected to use a threaded end cap at the top (where the rope comes out):
He may have done this so he could later unscrew it and adjust the length of rope. Also, there is less chance of having visible glue on the rope.
All the rest of the joints are slip fitted here. It's very simple -- like assembling tinker toys. There is a PVC primer and glue that is specifically formulated to bond PVC permanently. The (purple) primer cleans the joint and the glue (get medium bodied blue or clear) does the gluing. Once dry and cured, it is permanent and very strong -- absolutely dependable!
I should add, anyone considering such a project should use "schedule 40" PVC. It is very common, thicker than some of the lighter classes and quite rugged. PVC is easy to cut with a hack saw (no special cutters required). All of this is commonly available at most hardware stores, building supplies, lumber yards, etc.
If someone were to replicate his, it looks like the material list would include
1 -- 10' section 1" sked. 40 pvc
2 -- 1" slip/slip 90 degrees
2 -- 1" slip/male thread 90 degrees
2 -- 1" threaded end cap (you drill the hole in the end)
4 -- 1" slip "T" fittings
1 -- small purple primer
1 -- small PVC med. bodied glue
4 -- feet rope (goes in, down, across top rung, up and out other side). This would be routed prior to final assembly.
2 -- snap fittings
2 -- Stainless padeyes with 3/4" machine screws, flat washers and locnuts
Foam, tape and zip ties to suit
Tentatively I would make the ladder a little longer -- easier to get your foot in the bottom rung when fully in the water -- am hoping to try his first and see how it works in deeper water. That can still be accomplished with the material list above unless you want to add another rung.