Some facts about motor gunboats in World War II

Motor gunboats were the most heavily boats for their size during World War II.
One boat called MGB 658 was armed with:

• 2 power mounted 6 pounders ( they were called this because they fired a shell that weighed six pounds) I am guessing they were placed at the back of the boat

  (These are just pictures of what the guns look like, and not what they look like                                              mounted on the boat)

• A pair of 20mm Oerlikon cannon (I am guessing on top of the bridge (the control room)

• One 20mm Oerlikon cannon on either side of the bridge

(Again, this is on a different ship than the one I am talking about)

• Two twin Vickers .303 machine guns on the bridge wings 

And this ship was under 150 feet long!!!

It also had smoke screen equipment, radar, and depth charges: underwater bombs used to destroy submarines

This is stuff I was interested in from the time period that I am learning about in school.