Marcon International, Inc. of Coupeville, Washington has been chosen to market four concrete caisson section constructed in 1981 to drill exploration wells in the shallow Beaufort Sea. The hollow reinforced light-weight concrete caisson sections, each abt. 69m long x 15m wide x 11.5m high and weighing abt. 5,000 tonnes, were designed and constructed for the Tarsiut Island project, the first 100m diameter caisson-retained island built for drilling in the Arctic offshore. The caissons were arranged in a square, backfilled and standing on top of submerged sand berm.