GoldenEye 007/Frigate

Rescue hostages
Run around finding soldiers holding hostages at gunpoint. The soldiers and hostages are placed at difficult angles. Even if you retreatm the hostages will die as the soldiers become aware of you. Kill the captors and any other soldiers that are nearby, and the hostage will start to run away and the message "Hostage released!" will appear at the top of the screen. Be careful of nearby computer consoles, if damaged they will exlode, injuring anyone around including you and the hostages. Later, when the hostage has gotten off the boat, the message "Hostage escaped!" will appear. You have to free more hostages on harder difficulty levels.
 * Difficulty level: Agent
 * Gadgets used: None
 * Objectives req'd: None

Disarm bridge bomb
Go to the bridge (the room near the front with all the computers and stuff in it). Take care of the guys, being very very very careful not to blow up any computers at the front and near the center of the room. (Don't shoot the hostage, either). Once you've taken care of that, look around for a computer in said part of the bridge with a little brownish-yellow thing on it. Arm the defuser and push the fire button after walking right up to it. Done.
 * Difficulty level: Secret Agent
 * Gadgets used: Bomb Defuser
 * Objectives req'd: None

Disarm engine room bomb
Same thing here, except you go to the computer in the engine room (that's on the bottom floor of the boat, BTW).
 * Difficulty level: Secret Agent
 * Gadgets used: Bomb Defuser
 * Objectives req'd: None

Upstairs in the engine room, you should be able to see the bomp on top of the comupters. Select the Bomb Defuser and press the fire button to disarm the bomb.

Plant tracking bug on helicopter
While running around freeing hostages, you might find a helicopter at the back of the boat. Go to the menu, and select the tracking bug. Press Z when you're facing the 'copter (and also reasonably close to it).
 * Difficulty level: Agent
 * Gadgets used: Tracking bug (duh)
 * Objectives req'd: None

At the front of the ship is a helicopter. Go to your invintory and select the Tracker bug. Aim at any part of the helicopter and press the fire button to plant the Tracker bug. You only have one so don't miss.
 * Notes: After planting the Tracker bug it is possible to shoot it off again causing you to fail the objective.