> How do they do it in an airplane? Static pitot tubes is one way (measurement of differential between static & dynamic pressures). Could conceivably work on a canoe, but I'd be concerned about it geting broken. Peter This email, its content and any attachments is PRIVATE AND CONFIDENTIAL to TANDBERG Television. If received in error please notify the sender and destroy the original message and attachments. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics