rudder cores

["Roger Wright" <rowr@xxxxxxxxx>]

I discovered today that my super light rudder blade cannot handle 20 
knots!!!

I was having a great sail with winds gusting around 15 to 20, (waaaay 
overpowered on 20 knots :) survival mode), I was trying to hold it all 
together without being seriously dumped, or thrown over the sail, when I 
heard this ominous craaack. I thought that I had ripped the tiller out of 
the transom by the way the boat reacted, but once I dug my mast out the mud 
and got back on- board, I found that my beautiful carbon rudder had snapped 
clean through at the bottom of the box.

I think that I used 2 s-glass, 1 kevlar and 2 carbon for this blade, making 
it super light. Upon inspection, I could also see the foam running right to 
the end of the carbon trailing edge, which means I did not have a really 
good bond on the trailing edge.

A few learning points here,
1. Maybe a little heavier lay-up for safety
2. Make sure that you have a carbon on carbon seam with a good bead of epoxy 
running the full length of the trailing edge on the inside.
3. Check the edges of your tiller box casing to make sure there are no point 
loads when using carbon blades.

Oh, and another thing, that thin shock cord on the trapeze wires does'nt 
stop you from hurtling right around the forestay on the wire while doing a 
really fast unintentional jibe downwind in 18 knots :)

happy sailing,
Mike, I am really glad this did not happen offshore at Jericho

Roger 


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