I have stayed afloat through countless boat wakes and sudden winds, if you are not comfortable with the canoe rockin over that kind of sea, then those places are not right for you to fish from a canoe. For me, breaking waves is when thing get real fun (wet). Before I fish a new area from a canoe, I always plan where I could put in if a big unexpected wind should come up and we could not paddle back to our launch. Only happened once, fishing for fun (not guiding) in a friends 19' Freighter canoe. The bay went from flat calm to tight 3 foots in a few minutes (another complete miss by the weathermen) and we rode it to a far shore and I walked back to the vehicle to do the pick up... At least we got a few nice striper on the fly rod before it started to blow... Boat wakes are not often that hard to stay upright in (when anchored it is even more of a challenge), but in the end it comes down to your ability, judgment and comfort level that dictate where you can fish...