As with the Fairey Battle earlier in the list, the Douglas Devastator represented a major advance on its predecessors. First flying in 1935, it was one of the first carrier based monoplanes, the first all metal naval plan and the first with a fully enclosed canopy. At this stage it was, arguably, the most advanced torpedo bomber in the world. By the time of Pearl Harbor it was, however, completely obsolete, yet with its replacement, the TBF Avenger, still in testing stages there was no alternative. With a top speed of 331kph (206mph) the plodding Devastator was gravely vulnerable to patrolling fighters. To make things even worse, the crude torpedoes it carried could not be released above 185kph (115mph) and often broke up or failed to explode. Testing had been carried out with dummy torpedoes with warheads filled with water, and little thought had been put in to how they would perform in combat