How to Be a Sailor is unique in the Goofy "how to" canon. Very often, the "how to" shorts revolve around sporting activities. This one is more occupational. It also is one of the only Goofy cartoons to address wartime conditions, and unexpectedly becomes a propaganda piece at the end. Usually, the war cartoon stuff was left to Donald Duck or Pluto, who were in the army during the war years. There is one Goofy short, Victory Vehicles which speaks to homefront issues like the rubber shortage, though it's mostly an excuse to show silly inventions and promote the pogo stick. How to Be a Sailor is the only Disney World War II cartoon to focus on the navy rather than the army. It's also one of the few that shifts attention to the war in the Pacific. This makes sense given the time of its release. Really the only other Pacific War cartoon is Commando Duck, and that one is far more racist and makes for uncomfortable viewing today.
This cartoon opens with a trend begun in several other Goofy cartoons, that of the "subject through the ages" motif. Indeed, for much of this short it feels less like how to be a sailor and more like the history of sailing. Some might note the similarity to the "History of Aviation" sequence from 1943's Victory Through Air Power. It's very different from the other "how to" shorts as the narration really is more of a history lesson and less of an instructional as in, say, How to Ride a Horse.
You may also note the use of more limited animation in this cartoon, particularly in the more detailed ships toward the end. Note that only the flags wave and the rocking in the ocean is minimal. During the war, Disney was forced to pioneer limited animation techniques to save money and time. Many of these techniques were employed mainly in the educational, propaganda, and military training shorts.
One thing that really stands out about this cartoon for me, though, is the animation of Goofy's walk cycles in some of these moments. The entire pirate sequence is a lot of fun, and Goofy's pirate captain walk where his head remains steady and only his body shifts is delightful. I think they sometimes used similar animation for birds in other shorts like pirate parrots. Maybe the lawyers walked that way in Who Killed Cock Robin? The image is certainly familiar. But in a similar vane, I enjoy the bit with Goofy's upper body maintaining steadiness while the whole ship rocks around him. This is a fun visual.
The intent of the short would seem to be that all the advances in naval history had prepared America to defeat the Japanese. The ending is really quite unexpected, as Goofy accidentally shoots himself out of a canon, only to take down an entire Japanese fleet. Of course, we know they are Japanese not only because of the Rising Sun behind them but because the vessels are anthropomorphized Japanese caricatures. In a clever ending, Goofy speeds toward the sun on the horizon, stylized as the Rising Sun of Japan and shatters it while the score plays "Three Cheers for the Red, White and Blue". It's a stirring bit of war propaganda and while the short on the whole is a middling entry in the Goofy canon, I consider that moment one of the best Disney propaganda moments of the war.