According to Clay Blair in "Hitler's Uboats" the U-30 initially fired two torpedoes. The first one hit the second did not (probably do to an erratic run). Upon observation that the Athenia was not sinking, the U-30 fired a third torpedo which also did not hit.

Blair does not mention any deck gun action. Shortly after firing the third toropedo, the U-30 was able to positively identify (through intercepted radio transimssions and periscope observation) the identiy of the Athenia. No further hostile action was taken on the Athena.

Since Oberleutnant Fritz-Julius Lemp was under the impression that the Athenia was an Armed Merchant, it is unlikely he would have considered deck gun action against the Athenia. After identifing the Athenia as being unarmed, there was no indication that Lemp ever considered additional torpedo or deck gun action.