Hollow Crossbeams







Hollow crossbeams or iako are very stiff and strong and avoid some of the difficulty of constructing a solid laminated beam.  In this case for my Wa'apa, I used 19mm (3/4") timber top and bottom with spacer blocks to hold them apart.  It would be okay to reduce the timber thickness to 15mm (5/8").  Draw the shape of the beam on a flat surface or put down some polytarp first to keep the glue off of your surface.  Screw a series of blocks along the line to which you will clamp the first member.  Glue and clamp the spacer blocks to the first member.


Glue and clamp the second member to the spacer blocks.

Glue and nail 4 or 6mm (3/16" or 1/4") plywood to the first side. 
       

                          

Bore a hole to take the hardwood dowel at the outer end.




Comments

  1. AnonymousJune 29, 2023 at 2:56 PM

    Question...I'm going to be building hollow box beams for my wa'apa as well, and wondered if I could forgo the 1/4" ply on the sides and just leave them exposed? Not sure if the beams would be more prone to twisting while under sail/pressure without the side panels though...thoughts? Thanks!

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  2. AnonymousJune 29, 2023 at 4:38 PM

    They might have less resistance to twisting but I think others have done it and had no problem.

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