Round ranger rigs

I decided to build swing rigs for the round ranger because; they appear to fit the hull better with its steeply sloping deck, are simple to make and take seconds to fit at the lake side. There are not to many components to make for a swing rig. There is the swing rig block which all the spars connect to and the mast crane. I initially made a swing rig block out some 10mm aluminum tube with a wall thickness of 2mm. This was bent to the desired angles and then drilled for the mast to pass through. I reasoned that the tube used needed to be as thick as possible to reduce the moment around the mast because the pultruded carbon tube I used has a very poor crushing resistance. To improve this I inserted a small length of 4mm aluminium bar bar within the mast where the block attaches. I used 8mm tube for the lower 400 mm of the mast and 6mm for the upper. The lower half of the mast was shaped to fit around the swing rig block which helps it fit securely to the mast and stops the block moving up the mast.

Although making a block like this it looks very simple but I found it quite tricky to make as it needs very careful bending to get the main and jib spars at the correct angle to the mast. The block also gives very little area to glue to the mast and if it fits the mast tightly any epoxy used will be scraped off during assembly. This made me adopt a different approach for the B and C rig where I made the swing rig block out of 1mm carbon sheet filled with epoxy microfibre. This method is described by Eric Rosenbaum at http://iomdesign.wordpress.com/rigs/ and is straight forward and allows very accurate placement of the spars which were tacked in place using thick cayno before the carbon plates were glued on.

Although the resulting block is heavier than a moulded carbon one at 7g it is comparable with the bent aluminium tube used for the top rig.

The mast crane was made out of 8 layers of 200g carbon cloth and epoxy. A crude mould was made out of two pieces of wood with a 7mm hole drilled between for the 6mm mast to pass through. the wood is covered in parcel tape and grease to ensure that it will release. A greased piece of 6mm carbon tube is inserted between the layers of wetted out cloth before the two pieces are screwed together and then clamped in a vice.

Once the epoxy has gone off the 6mm carbon tube can be removed (with the aid of a hammer). The mast crane shape is cut out using a dremel with a cutting disc and drilled.

The mast crane can be positioned on the mast before being glued in place using thin cayno. A micro magic boom clamp is used for the jib attachment allowing easy repositioning and maintaining the strength of the carbon.

I also tried making a mast crane out of a piece of 4mm carbon tube inserted into a strengthened section of mast

10mm lengths of 4mm diameter aluminium bar are inserted in the end of all tubes to stop the pultruded tube being crushed or splitting.