if there is no head shakes, its not a shark... sharks tails are like salmon, and they go from side to side, and that contorts the body side to side, hence easy feeling headshakes...

whales tails, are turned sideways, so the headshakes you are used to, would not be there at all... Orcas can swim fairly fast, for long periods of time, but, can only stay under water for like 15-20 minutes max, usually way less than that... Sperm whales on the other hand, can stay down for well over an hour, and an animal that big, you wouldnt turn, couldnt stop, and likely will never see....

the Minke, Grey, and Humpbacks are all very large whales as well, but are baleen whales, so i suppose it could be a foul hooked one, but multiple people hooking up to it, indicates that its biting something, or there is a very large population of whatever it is, to get snagged so frequently...

im now going with a Sperm Whale, they eat Squid, Octupus, other fish, and Sharks... they can swim 15-25 miles per hour for over an hour, and have been recorded stayin under water for around 2 hours...

i might just have to rig up the Hali rod with the Penn 149 and 300# spectra and go chase after it, it sounds like way too much fun not to....