▁step ▁before ▁rotation , ▁so ▁the ▁area ▁of ▁the ▁b ree ch ▁secured ▁by ▁threads ▁in ▁the ▁block ▁is : ▁ ▁This ▁was ▁a ▁major ▁improvement ▁on ▁previous ▁non - ste pped ▁designs ▁such ▁as ▁the ▁de ▁B ange ▁system , ▁which ▁had ▁only ▁a ▁single ▁thread ▁step ▁and ▁hence ▁only ▁half ▁of ▁the ▁block ' s ▁circum ference ▁had ▁a ▁thread ▁which ▁engaged ▁with ▁the ▁b ree ch , ▁necess it ating ▁a ▁fairly ▁long ▁sc rew ▁to ▁achieve ▁a ▁secure ▁lock . ▁The ▁much ▁greater ▁thread ed ▁area ▁of ▁the ▁Wel in ▁block ▁allowed ▁it ▁to ▁be ▁shorter , ▁allowing ▁faster ▁opening ▁as ▁it ▁could ▁be ▁sw ung ▁down ▁or ▁to ▁the ▁side ▁after ▁being ▁with dra wn ▁a ▁much ▁shorter ▁distance ▁than ▁previous ▁designs . ▁It ▁was ▁also ▁simpler ▁and ▁more ▁secure . ▁▁▁ ▁The ▁Wel in ▁b ree ch ▁was ▁a ▁single ▁motion ▁sc rew , ▁allowing ▁it ▁to ▁be ▁operated ▁much ▁faster ▁than ▁previous ▁interrupted - thread ▁b ree ches , ▁and ▁it ▁became ▁very ▁common ▁on ▁British ▁and ▁American ▁large ▁cal ib re ▁naval ▁art illery ▁and ▁also ▁field ▁art illery ▁above ▁about ▁ 4 . 5   in ches ▁( 1 1 4   mm ). ▁ ▁Though ▁the ▁US ▁Navy ▁was ▁offered ▁the ▁design ▁a ▁year ▁or ▁two ▁after ▁its ▁in vention , ▁they ▁decl ined ▁and ▁the ▁American ▁Beth le hem ▁Ste el ▁spent ▁the ▁next ▁five ▁years ▁in ▁trying ▁to ▁circum vent ▁Wel in ' s ▁pat ent , ▁before ▁having ▁to ▁buy