Naval Architecture Support Services to Military Sealift Command


Tridentis provided on-site support to the Naval Architecture Branch (N721) at Military Sealift Command (MSC) Headquarters at the Washington Navy Yard.  During the duration of this contract, a variety of tasks were performed.

Stability - Tridentis naval architecture services were applied to T-AKE, T-ATF, T-AOE, T-ARS, T-AGS, LCC-20, and T-AO vessels. Tridentis engineers updated the trim and stability booklets for multiple classes of MSC vessels including T-AKR (LMSR), T-AKE, and T-AO.  This included updating booklets for new tank arrangements, lightship weights and centers, loading conditions and instructions, as well as updating POSSE models to match.  Tridentis performed a review of the drydocking plans for the T-AO-187, performed a pre-drydocking block inspection, monitored the drydock evolution, performed a post drydocking inspection, and checked the vessel for damage, condition of paint and through hull fittings.

Arrangements - Tridentis improved the stowage and handling of small boats for T-AKE and T-ATF vessels.  Team engineers designed and drafted cradles for three workboats installed aboard the T-AKE class of vessels.  This work included structural fabrication details and stowage arrangements for four additional trailer-mounted workboats.  For T-ATF-168, Tridentis drafted RHIB davit installation details as well as a workboat cradle installation details.  This included electrical modifications and foundation structural arrangements.

Structural Engineering - Tridentis applied structural engineering knowledge in support of T-AGS, T-ARS, and T-AOE vessels.  Our engineer created structural reinforcement drawings for the main mast of the T-AGS-60, and reviewed an FEA analysis of the main mast in order to ascertain the impact of additional equipment placed on the mast.  Team engineers used this analysis to draft modifications to strengthen the main mast to handle the additional loads.  For the T-ARS class of vessels, Tridentis created structural foundation drawings for equipment within the central control station.  This included HVAC modifications and electrical modifications in order to complete the installation of the new equipment and the re-arrangement of the space.  For the T-AOE class of vessels, Tridentis designed and drafted modifications to the kingpost due to cracking at the base of the mast.  Team engineers developed calculations showing the increase in strength in the location of the cracking.  Tridentis engineers also provided multiple foundation drawings for the installation of various pieces of new and modified equipment such as oil coolers, water and fuel pumps, condensers, and motors.

Marine Engineering - Tridentis utilized marine engineering skills for several MSC ships.  Team engineers performed a review of the USS MOUNT WHITNEY (LCC-20) fire protection plan, drafted a revision to the structural fire protection drawing in response to space modifications including new laundry, scullery and galley spaces. For the T-AOE class of vessels, reviews were conducted of equipment removal routes for equipment within the auxiliary machinery spaces.  Team engineers created drawings for the modification of escape trunks and ladder wells in order to remove large pieces of equipment.  For the T-ARC-7 cable-laying ship, Tridentis designed and drafted transducer installation details.  In support of T-AKE, chock replacement drawings were drafted.  This included new chock foundations and cut sheets for upgraded chocks, and replacing the vessels’ older roller chocks.

Training - Tridentis also facilitated training opportunities with our customers and partner engineers.  Tridentis provided AutoCAD training for MSC personnel demonstrating drawing tools, dimensioning tools, and techniques for sheet setup, creation, and management. Team engineers attended POSSE training, learning how to model vessels, tank arrangements, designating space types, performing damage and intact stability analysis, loading conditions and speed power calculations.