portside. We're glad the craft has recovered but alas, we don't believe there's much you can do to prevent publication of the photo.
Public pix. You can't stop people from shooting photos of your boat if it is in a public place. The photographer is free to reproduce these photos for editorial purposes (informational uses such as the boat insurance article). The same may not be true for commercial uses (for example, an ad for boat insurance), because there is an argument you may be able to assert that people associate you with the boat and the use in ad implies your endorsement. That's expensive, and you may have to be a Tiger Woods to pull that one off.
Copyright issues. If you took the photo, or you acquired copyright from the photographer, you can claim copyright ownership and demand that the unauthorized use stop. (We have the feeling that's not the case.)
What to do? We like your suggestion to kindly ask that the author change the photo (or at least block out the name of the craft). Sometimes people can be surprisingly reasonable. If the author doesn't cooperate, there's not much you can do except hope it fades into obscurity.
BTW Dept. As the seller you probably know you can't conceal existing flaws. So if the incident caused damage, you may have a duty to disclose that. State laws may differ on this requirement.
P.S. Dept. You asked whether the reproduction was legally kosher? Not to put too fine a point on it but the true meaning of "kosher" is that something -- food or a ritual -- conforms to Jewish law. We couldn't find any Jewish boating laws but we did find evidence of Jewish copyright laws.