Okay kiddo, let me try to explain what initial stability means to you. Imagine you are trying to balance a pencil on your finger. At first, it's very easy to keep it from falling off because it's not moving much, but as you start to move your hand, it gets harder to keep the pencil balanced.
That's kind of like how initial stability works for things like kayaks and boats. When they are sitting still in the water, they are usually pretty stable and don't rock around too much. But as you start to move, especially if you are going over waves or rough water, they can become less stable and harder to control.
So when people talk about initial stability, they are usually referring to how stable and balanced something is when it's not moving much. If something has good initial stability, it will be easier to keep it from tipping or rocking around when you first get in or start to move. But if something has poor initial stability, it might feel wobbly or unstable even when it's not really moving.
Does that make sense, kiddo?