Slab Keel Balast

I would like to try a slab-design ballast on my keel, so the fin could be reversed. the fin will have a sweep to it and I would like to try out the different algles. The slab could also be designed to create lift, and decrease sideways resistance when the boat wants to heel.

My slab-design ballast would be a flat-ish block about 50x18x3mm with a square footprint and beveled edges. I thought about a disk-shaped ballast, but that’s about the same thing as a slab, but without the corners.

Has anyone tried this? Any tips?


Take a look at these 6 Meter class lead bulb keels during the 2007 UK R6M Nationals. They are hydrodynamically low drag and are proported to create a little lift. Rumoured to be slightly slower downwind although my Ravenna with said bulb is as blisteringly fast downwind as upwind. Hopefully some inspiration.

Those are good pictires.

YOur ballast is a LOT more developed than the idea I had, so I will keep that in mind for later on. Right now, I just want to stick something on the fin, so I’m going to make up a simple block and probably just file or sand the edges round, and see if it will go. :scared:


Glad Damian Ackroyd’s photos inspired you. Unfortunately my Ravenna was not at the 2007 Nats. It’s last outing was the 2001 Nats where she came in 3rd. My wing bulb is the same as the ones in the photos and is a Sails etc part.

Once you get your lead on post some photos and thoughts. It would be interesting to see a comparison to a normal round bulb…?

Il Moro from Victor Products used to furnish a rather flatish bulb with flat trailing end. Not quite as radical as yours, but similar in looks. I’ll have to look - I think I may have one at homes which hasn’t been glued up yet. They came in two parts.