I've been playing again,
I wanted to see how much these tiny wooden hoops could take when under load so I rigged up an apparatus with some old kitchen scales I dug out of my shed and some steel weights I have.
The scales are supported by the red hardwood beam which is held to my kitchen table top by a 6" G clamp. The 22mm x 5mm section obechi beam spanning the top the scales supports a wire sling below the scales and is able to swing freely.
This way the load is transferred to the laminated hoop and on through the wire hook, wire sling and odechi beam above it so that I can read the load directly on the scales
I wanted to mimic the load of a sail pulling at the mast via the hoop.
Bearing in mind the tiny size of 27mm internal diameter and profile of 1.5mm thick x 2.4mm deep, each ring could take an 750 gram load without deforming.
There are ten of these hoops on the trawlers 0.367m2 mainsail and a further nine on the 0.185m2 mizzen sail so I reckon these little hoops will easily take the strain.
Breaking load was found at 1500 grams!
The hoop took the 1500g strain for a full 5 minutes, elongating all the time until it finally broke!
I'm pretty impressed
since I used cheap white wood glue and the hoops were only made yesterday!
A post mortem of the failed hoop showed that it had de-laminated at the two points of load suggesting the lack of cure time of the glue perhaps or as I suspect a poor quality wood glue.
I'm popping out tomorrow for some cascamite to make another batch of hoops!
Incidentally the little black bits on the wire hooks the hold the hoop are halves of a rubber grommet as the wire alone would have created two tiny pressure points that would not occur on the actual sailing model - I wanted to be fair!