I broke a rudder off at high speed 2 weeks ago which resulted in the affected upper casting being disengaged, resulting in a loss of steering while at the far end of the hiking stick. The pitch-pole/cartwheel was so violent that the mast did not settle gently and float, instead it entered the water like a javelin and found the mud about 12 feet down in one clean motion. By the time I floated up and got the water out of my eyes to look around, it was obviously beyond the point of being righted without outside assistance.
The GPS track showed an average of 19 knots, I can't comprehend what I was doing when I hit the water... It felt like catching air from a wakeboard jump as I was catapulted off. I'm not sure if I hit anything, but only about a 3" tall portion was left attached to the lower casting. I did hear a loud bang, but didn't see anything but the rudder disappearing into the murky water.
Upon reaching shore, and flipping the boat on it's side (the main boltrope started to pull out of the comptip, and then jammed upon lowering to the aluminum part of the mast) I then took the opportunity to dissassemble everything. What I found was evidence of long term cracks within the rudder, bent bolts in the tiller/crossbar system (the short bolt attaches to the hiking stick) and a broken rivet in the affected upper casting. I think all were a result of age, and not the ultimate load that broke the rudder.
Take a look at the inside of that rudder... The grey area must have been stress cracked for a long period of time to get discolored like that. It appears that up until the final failure, about an eight of an inch at the leading edge, and about 3 linear inches towards the back was carrying the load.
I think this may be a lexan rudder from the 70's. My guess is that the casting "bubbles" were open-cell and allowed water in from the bolt-holes, which later froze. Aside from that, at least thirty years of aging took its toll! It had markings "AH" and what appears to be "XX1" if anyone can tell me that it is something besides nylon? It was yellowed with age... I bought a new one from Strictly Sail to replace it since I was afraid of getting a used/probably lexan rudder off ebay (be warned, fellow shoestring budget sailors!)
Here is what I learned:
1. Dissassemble/inspect things before they break
2. leave your phone/radio tied up on the trampoline in a waterproof case instead of in a hull that may end up getting submerged
3. It's possible to turtle "instantly" running downwind in 30mph gusts if your boat somersaults and wind gets under the trampoline (I was about 135 off the wind, but gusts were much closer to 180!)
4. A spare parts kit should have several long zip ties to secure a casting if a rudder breaks through a bolt hole. After righting the boat, I had to remove the hiking stick and use the crossbar like a tiller extension. At which point the your trap wire becomes useless because you are now stuck with your rump on the tramp in high winds.
5. the bottom of the hull is really slippery when you have a lot of wave action and you are trying to keep you mast from being bent. Wear water shoes.
6. I doubt a used rudder is worth the cost savings, even if you are sailing a beat up $500 boat