As Obelix stated, download JSGME and extract the UI-Boat folder into the Mod folder JSGME creates within the SH5 File folder.
Then Open JGSME and activate the mod (WIll appear on the right of JGSME).
An alternative method (Without JSGME) is to copy the folders within the UI_Boat archive into the SH5 folder overwriting the original files - but I reccomend using JSSME
