Why didn?t lutenant. Robert manor have any cannons when they attacked blackbeard?

In answer to your question I believe the person you are talking about
is Robert Maynard, he was the lieutenant that killed Blackbeard.

The reason that he had no cannons was because they were sailing around
Ocracoke Inlet off the coast of North Carolina. This area is known for
its undeveloped barrier islands and shallow water.

Robert Maynard knew that Blackbeard knew the area much better than he
so his only chance of winning, and navigating the area without running
aground was to use a type of ship called a SLOOP.

A sloop is a ship in the region of about 30 foot long. Much too small
to be able to carry many cannons and still keep it fast and floating
in shallow dangerous waters.

After Blackbeard attacked first using his cannons Robert commanded his
troops to hide below deck and pretend they had all been killed. From
this Blackbeard boarded the ship belonging to Robert and started to
kill the wounded. Once Blackbeard's men were on board the Royal Navy
sailors (who had not been drinking unlike Blackbeard's) were able to
kill the sailors and left Robert and Blackbeard fighting. After 40
Cutlass wounds and 6 pistol shots Robert severed the head of
Blackbeard from his body and hung it on his mast to show he had
defeated the most notorious pirate at the time.

Hope this helps,
--Keystroke-ga.

If he won, he didn't need cannons; if he lost, he was foolish.

Thanks for the five stars and the tip, tommysam.