I like the positive mental attitude in the hope of plural sightings but sadly, from San Pedro, your chances are close to zero - although they are out there, it's a big sea. Reliable sightings are found a week or so either side of the full moon March - June where they feed late afternoon at the Snapper spawning grounds off Gladden Spit east of Placencia.
Contact Brian Young at SeaHorse Diving for more accurate info and if you fancy a trip from there he is your man - I have been lucky enough to see them each time I have been out with him over the last four trips. Words do not do justice to a sighting. Yes Craig, I was looking the wrong way to see the alleged Hammerhead!!