I have a 82L 2009 JP RWW Pro editon (biax carbon)
I only use it on maxing days as a bump and jump or when the wave conditions really suit.
The issue is, it's a single fin and i'm greedy and want more fins.
Jokes aside, the board is in great condition and i can't fathom selling it to replace it with a similar sized multi-fin board.
So i want to convert it to a thruster however my skills in modifying boards/fin boxes is limited.
I can do basic board repairs and dings etc and have set fins on surfboards but this is next level.
Would anyone out there be willing to sacrifice their time and tooling/shed to teach me how to complete a fin box addition?
Routing, Vaccum Bagging, toe and camber alignment etc..?
Money and Beer as payment.
There's a guy in Gero i think could teach you a trick or two and the payment currency would suit him quite well. But you'd need to go to Gero. not a bad trip.
What a coincidence look what I started today.... www.seabreeze.com.au/forums/Windsurfing/Western-Australia/What-s-Mike-up-to-now---continued--#2222165
Hi Stu,
I smashed the tuttle box out of my Patrik last year and repaired it with a new box, came up sweet. Let me know when you want to come up and have a crack mate.
Mike
Some more detailed info for Stu who will be attempting this on his board.
The fin boxes are surrounded by some high density foam this adds sideways support when load is applied to the fin, It also stops water entering the board if you hit a rock and crack the box which happened to me last summer and no water in the board. When making a board I normally put a whole block in from deck to bottom. As this is a retro fit and 4 boxes I'm trying to save some weight. I try and make the blocks 1.5 cm border around the box eg if box 20mm wide then block 50mm wide. The HD PVC I managed to get is only 25mm thick I want it 30mm thick I will glue a 5mm piece onto the top of the block.I routed slots as deep as my router 30mm then used a 6mm drill bit in drill to go deeper to the deck. Shaped the HD PVC to fit inside deck contour.I glued the HD PVC in last night with a mix of qcell and 30ml of resin to a thick sour cream consistency. I will route out holes for the blocks sat 50mm x 185mm x 30mm deep glue them in as above mix.Then when dry route out holes for the fin boxes and glue in with resin qcell (sand boxes for resin to key into)and 1 layer of 4 oz glass, let dry sand flush, glass over the top 3 x 4oz layers, filler, sand, spray, route out fin hole slot.
Another pic of what I glue inside the board but it's upside down the deck is the top curve of pvc and bottom of block is bottom of board. Does this make sense?

Yep. So the shaped deck piece ends up butting against the other core cell piece which you then router the fin box in to.