• Home
  • >
  • Projects
  • >
  • New Life for Dredge Tender Ivanoff

    The dredge tender Ivanoff was built to maneuver the Port of Portland’s dredge Oregon along the sites it dredges on the Columbia and Willamette rivers, working to maintain important navigation channels. The Ivanoff was lacking in propulsion and steerage both ahead and astern to meet the Port’s operational needs. Despite having more power, the Ivanoff was routinely outperformed by the Port’s other dredge tender, the Clackamas. As a qualitative test, the Port chose to perform a push test between the Ivanoff and the Clackamas, which the Clackamas handily won.

    Understanding an Underperforming Vessel

    In 2015, the Port of Portland commissioned Glosten to investigate design improvements to the Ivanoff. Glosten deduced that the Ivanoff’s performance issues were related to the stern hull shape, rudder configuration, and propeller sizing. After discussions with the Port, it was determined that the best solution would be to completely redesign the vessel’s stern and propulsion system, with the goal of enabling the Ivanoff to perform the necessary dredge handling operations.

    Analyses and Comparisons

    A qualitative baseline for comparison of the Ivanoff’s new stern hull design was accomplished by computational fluid dynamics (CFD) analyses using 3D computer models of the original Ivanoff hull and the Clackamas hull. These analyses provided quantifiable metrics that showed the Clackamas hull was superior to the original Ivanoff hull, matching the real-world results of the push test. Glosten then designed a new Ivanoff hull and modeled the design to  compare with the Clackamas. The analysis showed a significant improvement over both the original Ivanoff and Clackamas hulls. Additional design work was done to change the vessel’s drive gear reductions, propellers, and rudders to facilitate the Port of Portland’s desired performance improvements.

    Real-World Results

    The Ivanoff began her transformation in early 2016. The selected shipyard, JT Marine,  hired Glosten’s Production Services team to provide detail design for the retrofit. Since leaving the yard, a bollard pull test confirmed that the newly-modified Ivanoff exceeds the bollard pull of its old design by 29%, as well as exceeding that of the Clackamas.

    How can we help you?

    At Glosten, innovative thinking is grounded in a comprehensive understanding of all things marine.


    The Harvest: A US-built Liquefied Gas Carrier Barge

    , ,

    The Harvest is the first liquefied gas carrier of its kind to have been built in the US in three decades. The vessel is a 508-foot-long unmanned Articulated Tug...

    Read More

    A Midlife Refit for the Roger Revelle

    ,

    The R/V Roger Revelle is an auxiliary general-purpose oceanographic research vessel operated by Scripps Institution of Oceanography. Glosten was selected by the Office of Naval Research to design the...

    Read More

    The Atlantis Gets a Refresh

    ,

    In 2012, the University of Washington awarded Glosten a contract to evaluate midlife refit options for the three AGOR-23 Class research vessels. The Thomas G. Thompson, Atlantis, and Roger...

    Read More

    The HT-60: A Modern “Do-it-all” Harbor Tug

    , , ,

    Developed with input from experienced towboat operators, the HT-60 is the smallest of the Glosten-designed Harbor Series tugs. This workboat concept was designed to offer maximum versatility and capability...

    Read More