This paper illustrates the components, capabilities, and some characteristic applications of the Woods Hole Oceanographic Institution Jetyak - a small autonomous surface vehicle (ASV) designed for the collection of oceanographic data from shallow or dangerous waters. The Jetyak is the result of custom modifications to a Mokai jet-powered kayak, including an A-frame and sea chest for installation of instrumentation, servo-driven controls and an Ardupilot autopilot for autonomous operation, an onboard computer for instrument control and data logging, and radios for wireless operation and communications. With these modifications, the Jetyak's cost of replacement is less than $15,000 (excluding the cost of instrumentation payload). The paper addresses the strengths and weaknesses of the Jetyak relative to piloted small boats and jetskis, autonomous underwater vehicles, and existing ASVs. Preliminary data are included from some shallow-water and dangerous Jetyak field campaigns in order to illustrate applications to which the Jetyak is well or uniquely suited.