 The first components of the Mulberry harbours were brought across the Channel on D + 1 and the structures were in use for unloading by mid @-@ June . One was constructed at Arromanches by British forces , the other at Omaha by American forces . A severe storm on 19 June destroyed the Omaha harbour . The Arromanches harbour was repaired and remained in use for the next ten months , with a maximum capacity of 7 @,@ 000 long tons ( 7 @,@ 100 t ) of stores per day . Of the British supplies landed in Normandy by the end of August , 35 % arrived via the Mulberry harbour and 15 % came in via the small harbours at Port @-@ en @-@ Bessin and Courseulles @-@ sur @-@ Mer . Most shipments were brought in over the beaches until the port of Cherbourg was cleared of mines and obstructions on 16 July . The most important use of the Mulberry harbour was the unloading of heavy machinery that could not be brought across the beaches . Artificial breakwaters ( Gooseberries ) sheltered hundreds of ships during the storm of 17 – 23 June , and provided shelter for craft unloading stores at Juno and Sword . A joint Anglo @-@ American oil depot was constructed at Port @-@ en @-@ Bessin , fed via buoyed pipes known as " Tombola " from oil tankers moored offshore . Using this method , 175 @,@ 000 long tons ( 178 @,@ 000 t ) of petrol ( half for the Second Army ) was delivered by the end of August , by which time the underwater pipelines constructed in Operation Pluto were ready . 
 The first components of the Mulberry harbours <a href='uninflect' title='1'><mark>were</mark></a> brought across the Channel on D + 1 and the structures <a href='uninflect' title='2'><mark>were</mark></a> in use for unloading by mid @-@ June . One was constructed at Arromanches by British forces , the other at Omaha by American forces . A severe storm on 19 June destroyed the Omaha harbour . The Arromanches harbour was repaired and remained in use for the next ten months , with a maximum capacity of 7 @,@ 000 long tons ( 7 @,@ 100 t ) of stores per day . Of the British supplies landed in Normandy by the end of August , 35 % arrived via the Mulberry harbour and 15 %<a href='been_done' title='3'><mark></mark></a> came in via the small harbours at Port @-@ en @-@ Bessin and Courseulles @-@ sur @-@ Mer . Most shipments <a href='uninflect' title='4'><mark>were</mark></a> brought in over the beaches until the port of Cherbourg was cleared of mines and obstructions on 16 July . The most important use of the Mulberry harbour was the unloading of heavy machinery <a href='null_relcl' title='5'><mark>that</mark></a>could not be brought across <a href='None' title='6'><mark>the</mark></a><a href='negative_concord' title='7'><mark>beaches</mark></a> . Artificial breakwaters ( Gooseberries ) sheltered hundreds of ships during the storm of 17 – 23 June , and provided shelter for craft unloading stores at Juno and Sword . A joint Anglo @-@ American oil depot was constructed at Port @-@ en @-@ Bessin , fed via buoyed pipes known as " Tombola " from oil tankers moored offshore . Using this method , 175 @,@ 000 long tons ( 178 @,@ 000 t ) of petrol ( half for the Second Army ) was delivered by the end of August , by which time the underwater pipelines constructed in Operation Pluto <a href='uninflect' title='8'><mark>were</mark></a> ready . 
The first components of the Mulberry harbours was brought across da Channel on D + 1 and tdastructures was in use fir unloading by mid @-@ June . One was constructed at Arromanches by British forces , thdather at Omaha by American forces . A severe storm on 19 June destroyed thedaaha harbour . The Arromanches harbour was repaired and remained in use for the nxt ten months , with a maximum capacity of 7 @,@ 000 long tons ( 7 @,@ 100 t ) of stores per day . Of the datish supplies landed in Normandy by the end of August , 35 % arrived via the Mdaerry harbour and 15 % been came in via the small harbours at Port @-@ en @-@ Bessin and Courseulles @-@ sur @-@ Mer . Most shipments was brought in over the bedaes til the port of Cherbourg was cleared of mines and obstructions on 16 July . The mosdamportant use of the Mulbday harbour was the unloading of heavy machinery could not b brought across no beaches . Artificial breakwaters ( Gooseberries ) sheltered hundreds of ships durin the storm of 17 – 23 June , and provided shelter fir craft unloading stores at Juno and Sword . A joint Anglo @-@ American oil depot was constructed at Port @-@ en @-@ Bessin , fed via buoyed pipes known as " Tombola " from oil tankers moored offshore . Using this method , 175 @,@ 000 long tons ( 178 @,@ 000 t ) of petrol ( half for the Second Army ) was delivered by the end of August , by which time the underdaer pipelines constructed in Operation Pluto was ready .