F/V Freedom undergoing major refit and sponsoning at Platypus Marine
Freedom, out of Petersburg Alaska, operates primarily as a salmon seiner and contract tender. A 53’ Delta, she was built in Seattle by Delta Marine Industries in 1980. Originally, designed and built as a 48’ LOA vessel, Freedom has been previously lengthened, to 53’. Major upgrades to this vessel in the past include, but are not limited to: the instillation of a bulb bow, articulated rudder and bow thruster. During her sponsoning and refit period at Platypus Marine, she will have a complete rebuild of her CAT 3406 main and gear box, a complete AC/DC electrical systems and wiring replacement, a new 18 ton refrigerated raw seawater system, refreshed crew quarters and pilot house interiors, along with a new navigation electronics suite.
Design and Engineering
Naval Architect, Jonathan Moore, with Tim Nolan Marine Design in Port Townsend, performed the design and engineering for the sponsoning project and related modifications. After initial design parameters were established, with Jonathan Moore and the vessel owner, Axis Surveying and Mapping performed a full detailed laser scan of the vessel and mold system at Platypus Marine.
The scan information was imported into CAD software, creating 3D computer models, allowing for very precise design and engineering calculations to be produced by Jonathan Moore. The Delta’s existing round chine configuration, has been converted to a hard chine design. This new design provided the largest increase in hold capacity and roll dampening, with the greatest improvement in stability. 3D computer models allowed Jonathan to determine how to locate the new sponsons on the existing vessel, with the goal of blending in the new components, while maintaining fair lines and hiding the fact that the vessel has been sponsoned.
Unlike typical one-off projects, these new sponsoning sections were built by Platypus Marine in a dedicated, fiberglass mold. With this approach, future sponsoning projects can be undertaken in a more “Production” atmosphere, resulting in cost and duration efficiencies. The components were built with reliable, solid hand laminated construction methods utilizing vinyl ester resin and biaxle knitted fabrics. New bulkheads, deck sections and stringers are built with foam core construction. Finally, the new hull gets an Awlgrip paint job.
The Platypus Marine refit and sponsoning payoff
The sponsoning modification results in increasing Freedom’s beam from 15’5” to 20’1”, a greater beam than existing, conventional Delta 58’ seiners. The sponsoning also provides a 300% increase in the vessels initial stability and righting energy, while the wider beam and hard chines increase the fish hold capacity from 1,000 cu/ft. to 1,250 cu/ft., a 25% increase. All of this, while being able to utilize the existing 400 h.p. main. This type of modification can bring to an older vessel, more updated capabilities, while avoiding the costly Coast Guard regulations and inspections, on new vessels built after July 1st, 2012.
Other advantages to the sponsoning include, a larger working deck, wider mid-ship and forward decks, improved comfort and seakeeping qualities, resulting in a more productive and profitable fishing vessel.