
Modelo à escala 1/20 do real com o comprimento de 1010 mm com reforço do casco e motorização com vista ao reboque.
Os planos utilizados para a sua construção foram gentilmente cedidos pela empresa Smalltugs do arquitecto naval Mal Low, a quem cabe o crédito do seu design.
Algumas notas sobre os parametros do original por parte del Mal Low:
"My design 625T
Persevere was developed to suit a very specific set of requirements. She was to be used by a marine contractor for towing barges with cranes and construction material for dredging, dock building, seawalls, etc. in the United States' Eastern Great Lakes coastal and inland canal regions.
Because she would be operating in shallow fresh waters, often with ice formation in the Fall and Spring, there were two conflicting requirements: Shallow draft and light construction vs. operation in ice with occasional ice-breaking duty. Additionally she was to use single screw propulsion powered by a Caterpillar D-397 V-12 NA diesel engine of 500 Hp (SAE) output at 800 RPM with a Caterpillar 3181 Marine Gear. This engine/gear combination weighs almost 16,000 lbs. The single drive train behind a full keel/skeg allows protection of the vulnerable shaft, propellor, and rudder in ice conditions.
Draft was to be limited to 5 feet and hull sheathing scantlings would be 1/4" and 3/8" plate to which was added an external ice belt of 1/2" plate from 12 inches above the DWL to 12 inches below it. Her bow is internally strengthened for light ice-breaking.
Her total displacement is 92,000 lbs and her draft with full fuel load is 4 ft.-11 in. LOA is 62 ft. with a Beam of 20 ft.
Persevere's superstructure is held within limits determined for bridge clearance in her area of operation; her mast is foldable.
In the Fall months U.S. Great Lakes weather is notoriously nasty as Arctic cold fronts start to move down in from Canada; and Winter is even worse. In construction duty she was apt to be caught in a hard freeze so her hull is designed to be capable of being "iced in" for short periods. Notice that her lines below DWL direct the pressure of the ice downward rather than in a crushing direction. Additionally it is important that her engine cooling and ventilation be able to be quickly adapted to Winter storage or "iced in" conditions. Because of this latter requirement she has keel cooling and her engine room intake air vent system has a quick sealing hinged cover over a large single vent system.
Persevere's accommodations were designed for a two man crew and occasional 4 man construction crew overnight use. All are housed in two cabins in the main deck forward superstructure. A full galley, lounge, head with shower, and laundry are included. The engine room overhead occupies the after part of the main deck superstructure. The bulkhead separating these areas is between the two doors visible on each side of the main deck level. The pilothouse was designed to have a full chart table and electronics rack as well as a day berth.
Persevere's Beam is slightly under my usual design standard to allow use in inland canals. Her Bitt layout is suited to the barge towing requirement and does not need a towing winch or hook. Her fantail counter is also a little lower and her forward deck a little higher to allow easy personnel access to barges and floating equipment alongside.
It was also necessary to give her a sea-kindly hull form for her open water passages in the infamous Great Lakes storms. Nevertheless, I attempted to give her the look and aesthetics of a traditional U.S. model bow tug and I believe she is also a pretty good example of my personal design style that I give all my designs. I am pleased with her and have determined that she meets all her design requirements."
Mal Low -Naval Architect, Gloucester, MA USA, June 2004