Let me go done and measure the diameters of my class 5 landyachts.

But before you spend any money make sure you can get hold of the glue. If you can't then buying SS stuff will be useless.

Also we need to work out how to test this setup before we have anything build. See later in this post.

....

Okay may two landyachts have a "pod" of :

-1- 60 mm x 4 mm steel ; length 420 mm

-2- 62 mm x 3 mm steel (even appears to be 2.5 mm wall) ; length 240 mm

The second pod (-2-) is the newer landyacht and before this one the builder had build at least 3 others. He said to me that a few lessons learned went into my landyacht. I bought the yacht of yet another person so the builder wasn't bullshitting me.

The bottom section of two alu masts I have/measured are 48x4.5 mm and 50x8 mm, the first mast quoted is the youngest.

Most of these components were chosen on account of their availability. Both yachts and masts were homebuild. Some drivers like to have their pod diameter to be noticeably larger then the mast bottom diameter so that the mast can move upright when riding downwind after being raked far back during the upwind. This has to do with the position of the weight and wheels of the craft. These considerations shouldn't concern us. So I guess we'll be smart to start at :

pod : 55 mm x 3 mm steel length 300 mm

mast bottom 50 mm x 5 mm alu.

This should give a rather tight fit. And 2 inch alu tubing has a 50.4 mm outer diameter so that should be easy to find in the USA.

I'm looking to make the mast pod something like this :




Where the top pod (steel tube) is welded to the bend steel plate and which is then later glued to the top of the alu 80x2 mm mainbeam.

I would like to go close to 180 degrees bend on the steel plate as that really helps avoiding tensile stresses in the glue layer. There is no need to go for a full 180 degree. Something like 160 will be fine. Additionally having a large wrap around really increases the surface area, resulting in lower stresses in the glue layer overall. This makes the joint more acceptable of "bad" glueing.

I also give you the design of a class 5 mast, again note that several methods exist to build up such a mast. My youngest mast uses less components as the builder was able to find tubes will thicker walls then 2 mm.






I want to test this setup under some considerable bending loadings fore-aft and side-to-side and see if the glue holds.

This means we have to lock the ends of the 80x2 alu beam in some way. Does anybody have a good idea on how to do this in an inexpensive manner. Remember this 80x2 beam will be under alot of torsion loading. Simply jamming it in a vice will most definately not work.

We could glue the ends to a wide wooden beam, making sure that teh glue area is many times larger then of the mast pod. These beams can then be linked up by a crossbeam from which to mount the mainsheet system. We then only need to insert a tube acting as a mast with a boom supported by a high strength line and start pulling it apart.





If this fails after say 3 times the expect laods then we will cut the pod increasingly smaller till the vertical part of the pod bends or deforms then we know hoe tall the pod at least needs to be. On the "standard" landyacht this pod looks rather short indeed.

Would something like this work for you Flatlander ?

Wouter