Here is the last born design of a SWING RIG for my Marblehead Studio3.
Instead of spending time in shaping balsa or other stuff and then laminating them with carbon/epoxy,
I decided to use what already available : the carbon tubes . My Rig is composed of the mast that start with a 14mm tube followed by 12 and 10 mm sections. The mast is split in with 3 equals tubes lenghts and do not requires the use of spreads being already rather stiff.
The booms are instead made with 6mm carbon tubes.
Following the drawing, the under deck mast length depends of the hull size. The holes are drilled so that the lowest 6mm tube is positioned above deck of about 15mm and the upper 6mm tube is positioned some 25/28mm above the lower one. The length will be chosen as fonction of the sail foot length. In my case the main boom is 450mm long and the jib boom 300mm long.
Once the holes drilled into the 14mm mast tube, the 6mm tubes are glued with epoxy.
To follow the correct assembly I use to deposit flat on the floor the various components on a scale 1:1 drawing as such to observe the angles of the booms with respect to the mast tube. Generally I fix the tubes as such that the extremes are somewhat at 40mm above the mast attachment ( see drawing)
In order to make a strong assembly I fill up the volume inside the mast, with a mixture of epoxy resin and silicium powder in yellow. To avoid propagation, I put a stopper in blue (balsa or foam) – the filling is done with the up side down position until is set. The quantity of resin should be sufficient to fill up for about 45mm. On my assy I added some reinforcements with 200g/m² tissu arount the mast. Similarly could be done at the extremes ends of booms.
Here is the drawing and the photo of my Rig.
This assy is very strong (actually still in use) and the full rig type B weight is only 289g using poliester drawing film sails of 86g/m².
Sorry for the short titles languages, Italian and French
The white spots visible in the picture on the lower side, are teflon rings .
Claudio
