Yes, we've covered this before. Lot's of interesting history associated with this. Their grandmother was Julia Gardner whose father David was killed in the Peacemaker explosion on the Potomac:



A number of Tyler's cabinet were killed in this incident but Tyler was spared as he was below decks courting Julia. She became the first first lady to marry the president while in office. Julia was only five years older than Tyler's oldest daughter by his first marriage, Letitia. Tyler became a Confederate congressman and when he died in 1862, Julia became the lover of James Semple, A Confederate naval officer who would be put in charge of the Confederate treasury when Richmond was falling. Semple was actually married to Tyler's daughter Letitia, when he became Julia's lover. Semple suppsedly hid the "missing Confederate gold" that gold prospectors are still looking for hidden near trees that he left cryptic carvings in at several locations throughout the south..

The Peacemaker was designed by John Erricson of USS Monitor fame and had a twin cannon that was never ever fired again due to the incident on the USS Princeton. If you go to the main gate of the USNA you can still see the twin.