 Though the Dahlgren smoothbore cannons were fairly modern most of the other original armaments were antiquated; such as the 32-pounders, or modified; such as the 42-pounder "rifles" which were in fact, old smoothbores that had been gouged out to give them rifling.These 42-pounder weapons were of particular concern to military commanders because they were structurally weaker and more prone to exploding than purpose-built rifled cannons.Additionally, the close confines of riverine combat greatly increased the threat of boarding parties.