Flag Signals Shallow Water
June 1963…
Flag signals shallow water. At low tide or in unfamiliar water, you’d navigate more confidently if you had a flag-ended feeler like this pivoted to the hull of your boat.
Opposed springs normally would hold the arm upright. On contact with an obstruction, the flag would dip, alerting you to shallow waters and therefore help you avoid a fouled prop or scraped bottom.e safely closed by leaving the net up.