Handmade Boat Propellers : Close to Perfection／手製船用螺旋槳 品質盡善盡美
Handmade Boat Propellers : Close to Perfection
◎English translation: Peng Hsin-yi
Kaohsiung is Taiwan's leader in terms of maritime industries. Businesses which serve shipping and fisheries prosper in the city. Among them are three manufacturers in Cijin District which produce handmade boat-propellers, mainly for fishing vessels. Handmade boat-propellers are popular because of their good quality, and also because there is potential for customization. Sizes range from small (weighing 35 kg) to very heavy (up to 1.2 tonnes). Offshore-fishing boat owners are the most loyal customers.
Boat-propeller makers must work in a high-temperature environment, and this deters a lot of people from taking up the trade. However, thanks to the high quality of such propellers, demand is consistent. Mr. Lin Jhe-cyuan, the owner of Jhe Cyuan Industrial Service, has been making high-quality propellers since boat-propeller manufacturing began in Taiwan. He shared his story of how he mastered boat propeller manufacturing and earned his reputation.
When Mr. Lin was 15 years old, he started an apprenticeship in a warehouse. Mr. Lin recalled that Taiwan had just started to manufacture propellers at that time. Because no one could share their experience with him, he had to figure out how to make boat propellers all by himself. Now that he has accumulated a great deal of experience, Mr. Lin has memorized the reduction ratio, dynamics, weight, horsepower, and number of blades needed for propellers used by certain types of boats. Mr. Lin's professionalism is second to none. Ten years ago, Mr. Lin started his own business after raising enough funds to go it alone. Mr. Lin says that manufacturing boat-propellers requires technique, labor, and patience. One has to very detail-oriented. Boat propellers are critical because they can affect the success of a fishing expedition.
Handmade boat-propellers are manufactured with clay, using a special molding technique. For this particular technique, it is essential the clay mixture has the correct viscidity. Mr. Lin and his team cover propeller models with the clay mixture to shape the blades, and to make the upper and lower parts for each blade. The clay molds will be smoothed by a scraper. If there are any bumps on the molds, the team needs to further polish it. Mr. Lin says they have to be meticulous because seawater can cause cracks on propellers. If the cracks are serious, the propellers' performance will be impaired. The team then uses charcoal briquette to heat the mold, and prepare bronze or aluminum alloys which are melted and poured in. The team has to pay careful attention to the temperature because different materials have different melting points, ranging from 1,100℃ to 1,600℃. The molten metal has to fill the mold within 15 to 20 minutes. Otherwise, the mold will crack as it cools, due to the wetness of the clay mixture.
When asked about differences between handmade boat-propellers and those manufactured by computer-controlled processes, Mr. Lin answers that computers can achieve a level of accuracy that human beings cannot, but handmade propellers can be customized based on boat specifications to better meet clients' needs. Boat-propeller manufacturers always engrave designs on propeller blades for decoration, thereby displaying confidence in their work.
手製船用螺旋槳 品質盡善盡美
◎文／侯雅婷
高雄為台灣漁業重鎮，海洋關聯產業蓬勃發展，其中手製船用螺旋槳製造業在旗津區中洲聚集3家，主要提供漁船使用，由於質、量俱佳，且可客製化，小至35公斤、大至1.2噸皆可承作，國內近海漁船船主是最忠誠的擁護者。儘管炙熱辛苦的工作環境讓不少人打退堂鼓，但憑藉擲地有聲的好品質 ，讓手製船用螺旋槳至今仍保有一片天，走訪「哲銓工程行」，經營者林哲全螺旋槳製作資歷40年，從台灣船用螺旋槳製造業起步迄今，堅守本行也守護品質，聽他娓娓道來如何無師自通，打下一片江山。
林哲全15歲就至五金製造廠當學徒，他談起，那時正值台灣五金產業剛開始試著製作船用螺旋槳，少了經驗傳承、全憑自行摸索，時日一久，從船型配備的減速比、動力、重量和馬力，需要搭配幾片葉子的螺旋槳都瞭然於心，紮實的基本功自不在話下，直至10年前，累積所需資金後，方才跨出創業這步。林哲全說，這行講求技術、勞力和耐心，一點也馬虎不得，螺旋槳的品質優劣關乎出海捕魚作業能否順利進行，不可不慎。
手製船用螺旋槳使用黏土「翻砂」製成，光這拌土就是門學問，得將土的黏性調和得恰到好處，覆蓋著螺旋槳模型並順著葉片塑出弧度，製出每片葉子的上、下模型，接著再以刮刀刮得無比平滑，察覺到有一丁點不平整，都得重新修過。林哲全指出，這般挑剔是因為船一旦下海，海水是最嚴苛的測試者，沖刷後就會出現裂痕，嚴重的話會影響到船行進間螺旋槳的性能表現。之後下方再堆疊原子碳燒成模型，這期間得備妥要灌注於模型內的青銅或是鋁合金，熔銅的節奏也得精準掌控，每批物料因材質差異，導致熔點有所不同，其熔化溫度為1100度至1600度，並得在15至20分鐘內將熔成的液體原料灌入模型內，由於模型下方的土散發濕氣，倘若等模型變冷才注入，模具就會有龜裂風險。
當被問及手製與電腦生產船用螺旋槳的差異，林哲全表示，使用電腦的精準度是手工所不能及的，然而手製可依著船的需求和狀況，客製化服務更貼近使用者需求。螺旋槳完成前，每家業者都會於螺旋槳葉片上刻上圖騰，襯得葉片更美麗，在自信之作刻上獨門印記，這是屬於職人的驕傲。