Yes the flood was worldwide.
Source from:
In the Beginning: Compelling Evidence for Creation and the Flood - A Few of the Mysteries
Mid-Oceanic Ridge. One of our planets most dramatic features and the earths largest structural feature, the Mid-Oceanic Ridge, was discovered in the 1950s. It wraps around the earth and is the worlds longest mountain range46,000 miles. Unlike most mountains, it is composed of a type of rock called basalt. Because most of the ridge lies on the ocean floor, relatively few people know it exists.
Figure 44: World Ocean Floor. Notice the characteristic margins of each continent. Seaward from each ocean beach is a shallow, gradually sloping continental shelf, then a relatively steep drop, called the continental slope. This strange pattern is worldwide.
The hydroplate theory proposes that:
a. These continents were once in the approximate positions shown in
Figure 53. (below)
b. They were connected by rock that was rapidly eroded and transported worldwide by erupting subterranean water.
c. As these eroded sediments were deposited, they trapped and buried plants and animals. The sediments became todays sedimentary rock, and buried organisms became fossils.
d. The continents quickly slid on a layer of water (rapid continental drift) away from the rising Mid-Atlantic Ridge and toward the subsiding Pacific floor. They came to rest near their present locations.
Figure 53: Continental Plates on a Globe. By far the best fit of the continents is with the base of the Mid-Atlantic Ridgenot with other continents, as shown in Figure
52.
All along this globe-circling rupture, whose path approximates todays Mid-Oceanic Ridge,
52 a fountain of water jetted supersonically into and far above the atmosphere. Some of the water fragmented into an ocean of droplets that fell as rain great distances away. This produced torrential rains such as the earth has never experiencedbefore or after. In other words, the flood of Noah's time.
Figure 59: Flood Phase. Sediments in the escaping water increased until their volume nearly equaled the volume of water gushing out. These suspended particles quickly settled and buried plants and animals in a chaotic mixture. During this phase, a phenomenon called liquefaction sorted sediments, animals, and plants into horizontal layers that are more uniform and cover a much larger area than sedimentary layers laid down today. Traces of these dead organisms are called fossils.
I just put some of the more basic info above, to get a full understanding go to the link I put above.