So how much clothing does one need to sail around the world? Not much really, if you stay in the warmer climates. Maybe 5 T-Shirts, 4 swim suits, 2 pairs of blue jeans, a light jacket, 3 pairs of under clothes, 2 sweatshirts, 2 pairs of socks, 1 pair of sneakers, 3 pairs of shorts, and 1 pair of flip flops plus one set of "presentable" clothes (button down, under clothes, simple slacks, black socks, and nice shoes).
Why so little? Because you can always pick up what you need as you go.
But why the "presentable" clothes? If you find you have to meet with local government officials to obtain visas or to address some law infraction you were unaware of, showing up in flip flops, swim suit, and a t-shirt won't help your case. In many 3rd world countries, one is expected to show respect by dressing more formally. No, an Armani suit isn't appropriate, but neither is t-shirts, flip flops, and a swimsuit.
There is a balance of course. If you dress too fancy, then the locals may assume you have lots of money and you can afford to pay bribes. Having traveled to over 25 countries, this is an all too real situation. So, wear nice clothes, not bum clothes and not a 3 piece suit.
Each of us will have 1 set of "presentable" clothes kept in sealed bags to keep them clean. When we arrive at a new country and we have to disembark the boat to visit a local government office, we will dress in our "presentable" clothes.