How far are these two ships from the shore?

Two ships $P$ and $Q$ are simultaneously observed from two points $X$ and $Y$ on a straight coastline running from west to east. $P$ is due north of $X$ and lies on a bearing of $300^\circ$ from $Y$. $Q$ is on a bearing of $040^\circ$ from $X$ and on a bearing of $010^\circ$ from $Y$. If the distance between $X$ and $Y$ is $4$ miles, calculate the distance of the two ships from the shore.