Shell Closures – Ice Breaker Doors



  • (3) Hinged Doors – all rotating 0-180 degrees with shipboard combing
  • Hydraulically operated with Electrically Driven Rescue Winches
  • Hydraulic cylinder locking pins & sockets
  • Manual and Electro-hydraulic control options
  • ABS Rules for Building and Classing Steel Vessels (Polar Ship Certified)
  • ABS Approved Welders and Weld Procedures
  • ABS Design Submittals, Test Plans, and Quality Data


As far as environmental conditions go, it doesn’t get more frigid than where ice breaking vessels operate. In one case, the client needed a horizontally hinged door that ultimately weighed in at more than 50,000 pounds and measured 34’ wide and 24’ tall.

Engineering for such conditions involves accounting for many external factors: polar rating, water tightness, wave slap, and high wind load, to name just a few. Mechanically, the door had to swing a full arc of 180 degrees upward from vertical, in a high sea state, with two inches of ice on its surface.

Clearly a challenging job; luckily, SIT has plenty of experience integrating custom systems into ships. For this project, SIT engineers had to be conservative in concept but innovative in design. Fulfilling the requirements meant taking special steps; everything had to be line-bored and precision machined. Hinges had to actually wrap around the outside of the combing to meet articulation and structural strength requirements. Many specialty hinges and linkages were involved that were manufactured to the tightest of tolerances.

Despite the challenges, the work turned out fantastic. Not only is the door one-of-a-kind, but it’s completely self-contained: the client needed only to hook it up. The conservative engineering of the door ensures that it will work in many environmental conditions, with reduced risk of critical failure or costly maintenance.