What KB and Nohuhu said!
I'm still on the original TI pin but on my older AI I broke 2. The first was in around 25knots of wind and I tried to fix it on the water but it was too rough so I headed to shore. I furled the sail to a 'handkerchief', dropped the daggerboard and steered using the paddle while pedaling as well. Worked OK.
The second time I was able to fix it on water as I detailed here in an earlier post:
"Broke my second rudder pin last week. It had been in about 3 months. This time I was able to replace it easily on the water and continue on my way.
Winds were about 8-10 knots with stronger gusts and I had just commenced a tack upwind when the pin snapped at the lower end causing the rudder housing to kick up. It stayed in place though, unlike the first break when the whole housing was trailing behind held only by the rudder lines.
I furled the sail, uncleated the down line, grabbed the spare pin and headed aft. Kneeling on the rear hatch/well I was able to release the housing by wiggling it. The broken pin came out easily and it was just a matter of lining up the holes on the housing and the hull and inserting the new pin.
My GPS plot shows just what a minor inconvenience it was!
If I had no landing alternative in rough conditions I think I would drop the mast and tie it off to the aka to help stability, lower the daggerboard and then head aft much like KB has described.
If you don't think it's possible to change at sea then you should practice steering using a paddle. Remember to furl the sail to a manageable size for the conditions and drop the daggerboard so you don't overpower the paddle. Supplemented with pedaling you should be able to make land OK.