A Photo & Discussion Forum for Wharram Design Enthusiasts
I have used silica flour(finely ground up sand) and epoxy. I am very happy with this using it on the bottom of my keels, skegs and rudders. I also applied it a little way up the keel(around 80 mm) because the keels sink down into the sand and can come in contacts with all sorts of things wanting to damage your keels
The keels were already heavily glassed. This was keyed. I glued on some little spacing blocks to the required thickness I wanted.(approx 12mm) Once set I used a strip of hardboard (the width of the keel) as a former. I put polythene tape on the length of the former and prearranged blocks and wedges to hold onto the keel while it dried. I firstly worked glue into the keel, then mixed up a really thick brew of silica flour and epoxy( it needs to be really thick because it is very heavy and you want to eliminate sag. You can always fill later if you do get sag) I applied this to the hardboard strip and placed it onto the keel. I then held it in place with the blocks and wedges and trowled off the excess once the strip was firmly fixed.
This can be done in manageable sections depending if you are working alone etc. I went to a lot of trouble to do this but now I have complete peace of mind drying out in coral, shells or sand with stones. I coule actually dry out on a boat ramp if needed but I havn't needed to and a bottom with a bit of give is a more sensible approach. I used this on my T 30. I have sold this boat to good friends and know it is in great shape and plan to do the same to my new (used) T 38. Lastly no screwing into the keel!!!!
Good luck Brett
Do any sanding /grinding as soon as poss as this stuff is extremely difficult to sand. I also used a tiling trowel (with the little v's on its edge) to apply to the sides of the keel, skeg and rudder. As soon as this had tacked off I applied more to fill the v's
I also have to replace keel strip as original hardwood ? glued on 90% gone and rotten. Keel still very good underneath , no water penetration or sift spots.
After reading all posts I am thinking why not ad a srip of polyethylene , routed to contour of keel bottom by glassing over with a few layers of glass going some distance up the keel , then when starting to gell ada second , sacrificial strip by screwing with stainless screws into first layer ( carefull not to penetrate into original keel) of poly. Thiswill then clamp unto soft epoxy and mould a ferfect fit. One could then also add cheeck strips extending from bottom of bottom strip extending past top strip say 5 cm up the keel, screwed onto both strips again while epoxy is soft to mould a nice seating, providing more protection anda degree of mechanical bonding to keel. No rot , light , slippy , no corrosion betweem metal and screws , easy to replace by using original screw holes and not to expensive compared to kevlar brass etc. , no antifouling needed.