▁Navy ▁div ing ▁manual ▁provides ▁repet itive ▁group ▁design ations ▁for ▁listed ▁alt itude ▁changes . ▁These ▁will ▁change ▁over ▁time ▁with ▁the ▁surface ▁interval ▁according ▁to ▁the ▁relevant ▁table . ▁ ▁Alt itude ▁corre ctions ▁( C ross ▁corre ctions ) ▁are ▁described ▁in ▁the ▁US ▁Navy ▁div ing ▁manual . ▁This ▁procedure ▁is ▁based ▁on ▁the ▁assumption ▁that ▁the ▁decom pression ▁model ▁will ▁produce ▁equivalent ▁predictions ▁for ▁the ▁same ▁pressure ▁ratio . ▁The ▁" Se a ▁Level ▁Equ ivalent ▁Dep th " ▁( S LED ) ▁for ▁the ▁planned ▁d ive ▁depth , ▁which ▁is ▁always ▁deeper ▁than ▁the ▁actual ▁d ive ▁at ▁alt itude , ▁is ▁calculated ▁in ▁inverse ▁proportion ▁to ▁the ▁ratio ▁of ▁surface ▁pressure ▁at ▁the ▁d ive ▁site ▁to ▁sea ▁level ▁atmos pher ic ▁pressure . ▁Sea ▁level ▁equivalent ▁depth ▁= ▁Act ual ▁depth ▁at ▁alt itude ▁× ▁Press ure ▁at ▁sea ▁level ▁ ÷ ▁Press ure ▁at ▁alt itude ▁De com pression ▁stop ▁depth s ▁are ▁also ▁corrected , ▁using ▁the ▁ratio ▁of ▁surface ▁press ures , ▁and ▁will ▁produce ▁actual ▁stop ▁depth s ▁which ▁are ▁shall ower ▁than ▁the ▁sea ▁level ▁stop ▁depth s . ▁Stop ▁depth ▁at ▁alt itude ▁= ▁Stop ▁depth ▁at ▁sea ▁level ▁× ▁Press ure ▁at ▁alt itude ▁ ÷ ▁Press ure ▁at ▁sea ▁level ▁These ▁values ▁can ▁be ▁used ▁with ▁standard ▁open ▁circuit ▁decom pression ▁tables , ▁but ▁are ▁not ▁applicable ▁with ▁constant ▁o xygen ▁partial ▁pressure ▁as ▁provided ▁by ▁closed ▁circuit ▁re bre athers . ▁T ables ▁are ▁used