For the record, I’m a former salmon fisheries biologist, now retired. I have attended Orca symposiums put on by the National Marine Fisheries Service (NMFS). I have also some professional background in using a DC electric field to deter seal predation on salmon caught in gillnets. This study was published in a North American Journal of Fisheries Management, available upon request.
So with that preamble, I would advise against modifying your “fins” and rudder:
1) I don’t think it would deter the whales. If they had a mind to attack your fins and rudder, they will. As alluded above, they are highly intelligent and will figure out a way to destroy them anyways, if so motivated.
2) Those spikes will surely compromise the fins and rudder, with unknown consequences.
The only method I know that works for certain is “lethal deterrence”. I realize that is not possible in most circumstances and probably illegal in most jurisdictions, but that is the only known method that works for certain. A few have suggested “seal bangers”. I can tell you from experience they DO NOT even work on seals. They would likely make the whales more aggressive. In British Columbia there is a herring roe fishery and sea lions dive over the cork line of seine nets to catch and eat the pursed herring. 100 or more sea lions can be inside those nets and the damage to gear and catch is extreme. Seal bangers do not deter this activity and only serve to upset the environmentalists.
I might suggest you travel in a small flotilla at speed if that is at all possible. Perhaps if one vessel is attacked, the others could assist with hazing.
I wish I had better news, but I don’t.
Jim