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.