Puma 54
Design
The Puma 54 is based on the RG65 Puma / JIF 2 (in a similar manner to the Footy Puma 305 http://www.sailfootyuk.com/puma305.html). A quick calculation 540/650 x 850gms=706gms suggested that using the same sections (shadows) as the RG65 version would give a M540 displacement of around 700gms. With a bulb weight of say 400gms the rest would need to weigh around 300gms which should be possible.. Scaling the mast position used on my RG65 version suggested a mast C/L 15mm in front of the fin leading edge. A second mast location with the tube touching the leading edge was also included. For the radio installation a cassette with a Futaba S148 with extended throw for the sail and a 5gm servo for rudder. The sail arm would move beyond the side of the hull but as I was not using the full width of the measurement box, I could position the hull off centre if necessary. |
Build.
The Puma shadows were set at 53mm intervals. This allowed 10mm for the bow block. (rather than the bumper required for the RG65 version). I used 1/16th mediun hard balsa planks and alphatic PVA glue. As the planking progressed I added a small additional former half way between the bow and the first shadow to finish the lower planking on rather than try and plank all the way to the bow. Once all the planking was finished and dry the balsa bow blocks were added and a strip of spruce to protect the point of the bow. Hull and deck is finished using glass cloth and epoxy finishing resin. |
Rig
The sails are sized to fit midway between the maximum and minimum class size lines. The swing rig is based on the Stollery Footy balanced swing rig design (http://www.sailfootyuk.com/make-simple-soft-sails-for-a-balanced-swing-rig.html.) The Jib is double surface made from a thin plastic bag about half the thickness of the single skin main. |
Sailing
The sails need to be set as per a balanced rig footy – quite slack. http://www.sailfootyuk.com/setting-up-soft-sails.html Limited trials (mostly in Abington Park MYC mixed fleet racing) have shown the setup to be well balanced and it generally sails well. On tacks and reaches it will track straight with just a little rudder trim. In strong / gusty winds it sometimes needs full rudder to keep it straight. (perhaps an extra 10 or 20mm on the rudder length may help).The rear mast location does improve stability slightly in rough conditions. Performance is comparable with a Micro Magic and it is able to stay with Wee Nips and RG65s (depending upon the conditions and the skippers ability). |
Conclusion
Using a RG65 design reduced in length produces a viable M540 boat.
As with Footy’s a bigger rudder is a good idea.
The Gothic and Doppler RG65s would probably make excellent M540’s. If you have built a planked RG 65 you have the shadows ready to build a M540
Obviously the Puma 54 rig could be fitted to other designs – or design your own.
Paul Risdale
Using a RG65 design reduced in length produces a viable M540 boat.
As with Footy’s a bigger rudder is a good idea.
The Gothic and Doppler RG65s would probably make excellent M540’s. If you have built a planked RG 65 you have the shadows ready to build a M540
Obviously the Puma 54 rig could be fitted to other designs – or design your own.
Paul Risdale