In Star Trek IV: The Voyage Home Kirk and crew time travel to the 1980s and bring in to the 23rd century some humpback whales. Upon their return to Earth the alien probe promptly drains the power from their Bird of Prey, causing them to splash land in the San Francisco Bay.
At this point everyone evacuates, except Kirk who swims into the hold of the ship to free the whales. He does this by activating what looks to be a manual throw switch. This sets off (what I have always thought were) small explosives, detonating along the hull, cracking the ship open like an egg and releasing the whales.
I assume whatever Kirk did did not require any massive amount of power (such as opening a cargo bay door or using the transporter) as the ship was rapidly losing energy. But if they were explosives, when were they put there? Do Klingons often lace their ships with explosives that when set off would kill a large part of the crew whilst disabling the ship? Or was some other method used to get the whales out of the ship?