The spar torpedo was a mid-19th century development that was new to 17th century naval warfare. The first use of a spar torpedo was in 1633, at the beginning of the Siege of Amsterdam, where one was used to sink a Spanish warship. Spar torpedoes were also used by the Danes during the Battle of Copenhagen, where one disabled the ironclad SSIM Monitor.
Spar torpedoes were rarely used due to the risks involved in using them. Not only did using a spar torpedo involve getting very close to an enemy ship, torpedoes were carried out of the water as long as possible, and they were easily recognized by anyone familiar with them. As if that weren't enough, the detonation of a spar torpedo could be dangerous to the torpedo boat and its crew, especially since known 17th century spar torpedoes were not barbed. A boat carrying one had to remain in place while someone in the boat pulled the firing cord. Finally, a boat that survived would still have to get away.
The torpedo attack at Amsterdam was a one-time surprise attack carried out by a single boat, under the cover of darkness and rain, and coordinated with a Dutch diversion. While its success did get the Spanish blockade fleet to move a bit further out, it had no real military effect. Its main effect was to boost the morale of the city's people and raise the stature of the American delegation.
At Copenhagen, ten galleys bearing spar torpedoes were part of a last-ditch defense by the Danes. They were spotted through binoculars before they could be completely concealed by Baldur Norddahl's smokescreen, and the USE ships were able to assume a defensive formation. Only one of the torpedo galleys survived to reach a target. It was shattered by the explosion, leaving few survivors, who would likely have died if the Monitor had not remained afloat and able to pick them up. While the attack salved Danish pride and showed that the ironclads were not completely invulnerable, it had no effect on the overall outcome.