Development of a Folding Boat Anchor

Abstract: This report is the result from a Master of Science Thesis work at the Royal Institute of Technology, and is executed by technology student Kristina Ahlinder for the behalf of Design Company Top Notch Design AB. Top Notch Design wants to expand their range of marine products and look in to the market of boat anchors. The aim of the project is to develop an anchor for small leisure boats for the Swedish market with focus on usability and safety. A detailed informational study was executed at the beginning of the project. To collect information regarding how potential users experience current anchors on the market, a user test and a digital questionnaire was done. Through the questionnaire, the user test, requirements from the company and the informational study a criteria specification was made. Some of the criteria were that it should be an easy to stow day anchor designed for leisure boats up to 27 feet and have a maximal weight of 8 kg. Other important criteria were good usability and innovative and interesting design. The ideation stage of the project was mainly based upon brainstorming sessions. 11 concepts were sketched and prototyped in paper and wood. Ten of the concepts were manufactured in small-scale and welded together in steel, in order to evaluate the functionality. The anchors were dragged in a sandbox, and the drag-force was measured with a nanometer. The anchor that performed best in the drag test was a kind of foldable plow anchor. This is the concept that was chosen to be developed.The anchor was further developed and tested before being modeled in the CAD-program SolidWorks. The final design consists of a fluke and a shaft connected by a joint, and a handle for usability, ease of recovery and for getting it in the right angle on the seafloor. The anchor has an automatic locking mechanism in the joint, and rubber details. The anchor’s material is mainly aluminum and weighs 3.8 kilos and has a length of 48 centimeters.The anchor fulfills the criteria specification and most of the preferences and according to calculations the joint will hold for forces higher than 2000 N. The anchor will, according to calculations, have an approximate selling price of slightly over 500 SEK. According to feedback given by potential users, 40 % has a good impression of the anchor and 26 % could imagine buying it. The outcome is a new and innovation type of anchor that suits the modern small-boat owner. The anchor has to be tested in full scale with the correct materials to fully be evaluated. The anchor would contribute to the conservative marine market. The anchor would be a brave and interesting addition to the current anchor market, as well as to TND’s current marine products.