We made a retractable carbon fibre prodder to replace a fixed aluminium tube one which broke - for our 2tonne 30 1/2 foot racer cruiser. Over a 50mm oregon timber core - very slightly tapered at outboard end. Works perfectly, just a high strength spectra rope stay down to the cutwater for assisting to take the vertical load - no lateral stays needed. We got excellent advice and carbon braid and uni material from Dick at ironbarkcomposites. 3 braid layers, 2 uni layers, about 5mm wall thickness of the carbon layup. Epoxy resin. Needs 2 people to lay up the resin and carbon properly including steel roller to get the resin to soak through.......numerous other processes needed. Carbon material cost about $300 - resin and timber on top of that. Kevlar sock over the carbon where it comes out of the tube in the hull to avoid wear. This was our first carbon layup project and the stiffness of the resulting prodder is amazing.
It retracts into a tube in the topsides - pvc tube but strongly supported by stainless saddle and epoxy glass at the fwd end, and by ply deck head bulkhead at the inboard end. I can email you photos if you want.
Barry Colson wrote a good article here;
colsonyachtdesign.com.au/latest-news/For your S80 not sure why you don't simply set up a system off the foredeck and bow onto which to mount your alum symm kite pole - have it about 1.5m out from the bow and it shouldn't need any lateral or vertical spectra rope support. I have done this on a 24 footer. Not sure of your rig dimensions but there are numerous asymm kites for sale on the web which should suit. Draw up your rig with the 1.5m prodder and the luff length of the asymm should be about 1.1 times the straight line from the prodder end to the halyard exit box for a "reacher" type asymm, and about 1.2 times for a more broad running asymm.