During the 2nd World War the Royal Navy put all those sailors who had a stammer onto one Destroyer. Cruising the Atlantic the lookout spotted a periscope from an enemy submarine and shouted to the Officer of The Watch "Ppperisscope on ppppooort bbbow"
"Wwhherre" says the Officer.
"TTThherre" says the lookout pointing towards the periscope.
The Officer shouts "mmmann tthe ggguuns" "Tttakke Aaaim" "Fffiirrre"
And the gun went BBBBaaanggg.