"The motto of the Engineer Amphibian Command is "Put'em Across", and its principle is aptly put by Brigadier General Daniel Noce (1894−1976) , chief of the U.S. Army's amphibious operations in the European theater, who built this force from scratch. 'Water between us and the enemy is an avenue, not an obstacle' he says."
"There are four elements to the amphibian engineer's mission. First is water transport of combat units from a friendly 'near shore' to a hostile 'far shore.' Supported by naval and air forces the engineers must clear and mark the beach, unload supplies, demolish obstacles, build roads and lay out dumps for ammunition, gasoline and oil, water and rations. Their third job is the evacuation of the wounded, salvageable equipment and prisoners. The last gigantic chore is to resupply the combat outfits. All this may go on for weeks until adequate port and dockage facilities are available. E.A.C. personnel is trained to fight, but theoretically only 10% of their job is fighting."
They used amtracks, Ducks, barges and all manner of landing crafts to get the job done.
Click here to read more about landing crafts.
Click here to read more about Ducks.
Click here to read about the D-Day port Battalions.