Gibraltar's Force H involved:
The sinking of the Bismarck was an excellent example of combined arms at sea working together to sink a stronger opponent.
Although it was eventually able to get back up to twenty-eight knots, the temporary loss of its speed advantage allowed a Royal Navy task force, Force H, to catch up to it. Established to take the place of the surrendered French Navy in the western Mediterranean, Force H was based at Gibraltar. It consisted of the aircraft carrier HMS Ark Royal, the battlecruiser Renown and a light cruiser.
But Force H had to find it first. British intelligence had decoded some of the Kriegsmarine’s message traffic, which stated that the Bismarck was going to Brest for repairs.
Read the article at link.